Zeitschriftenartikel zum Thema „High resolution accurate mass (HRAM) mass spectrometry (MS)“

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1

Hines, Jolaine M., Irina Bancos, Cristian Bancos, Raman D. Singh, Aditya V. Avula, William F. Young, Stefan K. Grebe und Ravinder J. Singh. „High-Resolution, Accurate-Mass (HRAM) Mass Spectrometry Urine Steroid Profiling in the Diagnosis of Adrenal Disorders“. Clinical Chemistry 63, Nr. 12 (01.12.2017): 1824–35. http://dx.doi.org/10.1373/clinchem.2017.271106.

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Abstract BACKGROUND Steroid profiling is a promising diagnostic tool with adrenal tumors, Cushing syndrome (CS), and disorders of steroidogenesis. Our objective was to develop a multiple-steroid assay using liquid-chromatography, high-resolution, accurate-mass mass spectrometry (HRAM LC-MS) and to validate the assay in patients with various adrenal disorders. METHODS We collected 24-h urine samples from 114 controls and 71 patients with adrenal diseases. An HRAM LC-MS method was validated for quantitative analysis of 26 steroid metabolites in hydrolyzed urine samples. Differences in steroid excretion between patients were analyzed based on Z-score deviation from control reference intervals. RESULTS Limits of quantification were 20 ng/mL. Dilution linearity ranged from 80% to 120% with means of 93% to 110% for all but 2 analytes. Intraassay and interassay imprecision ranged from 3% to 18% for all but 1 analyte. Control women had lower excretion of androgen and glucocorticoid precursors/metabolites than men (P < 0.001), but no difference in mineralocorticoids was seen (P = 0.06). Androgens decreased with age in both sexes (P < 0.001). Compared with patients with adrenocortical adenoma (ACA), patients with adrenocortical carcinoma (ACC) had 11 steroids with increased Z scores, especially tetrahydro-11-deoxycortisol (14 vs 0.5, P < 0.001), pregnanetriol (7.5 vs −0.4, P = 0.001), and 5-pregnenetriol (5.4 vs −0.4, P = 0.01). Steroid profiling also demonstrated metabolite abnormalities consistent with enzymatic defects in congenital adrenal hyperplasia and differences in pituitary vs adrenal CS. CONCLUSIONS Our HRAM LC-MS assay successfully quantifies 26 steroids in urine. The statistically significant differences in steroid production of ACC vs ACA, adrenal vs pituitary CS, and in congenital adrenal hyperplasia should allow for improved diagnosis of patients with these diseases.
2

Wiesinger, Thomas, Thomas Mechtler, Markus Schwarz, Xiaolei Xie, Regine Grosse, Paulina Nieves Cobos, David Kasper und Zoltan Lukacs. „Investigating the suitability of high-resolution mass spectrometry for newborn screening: identification of hemoglobinopathies and β-thalassemias in dried blood spots“. Clinical Chemistry and Laboratory Medicine (CCLM) 58, Nr. 5 (28.04.2020): 810–16. http://dx.doi.org/10.1515/cclm-2019-0832.

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AbstractA fast and reliable method for the determination of hemoglobinopathies and thalassemias by high-resolution accurate mass spectrometry (HRAM/MS) is presented. The established method was verified in a prospective clinical study (HRAM/MS vs. high-pressure liquid chromatography [HPLC]) of 5335 de-identified newborn samples from the Hamburg area. The analytical method is based on a dual strategy using intact protein ratios for thalassemias and tryptic digest fragments for the diagnosis of hemoglobinopathies. Due to the minimal sample preparation and the use of flow injection, the assay can be considered as a high-throughput screening approach for newborn screening programs (2 min/sample). Using a simple dried blood spot (DBS) extraction (tryptic digest buffer), the following results were obtained: (1) a carrier incidence of 1:100 newborns (35 FAS, nine FAC, eight FAD and two FAE), and (2) no homozygous affected patient was detected. Using the HRAM/MS protocol, an unknown Hb mutation was identified and confirmed by genetic testing. In addition to greater specificity toward rare mutations and β-thalassemia, the low price/sample (1–2€) as well as an automated data processing represent the major benefits of the described HRAM/MS method.
3

Lanzon, Borja, Marina Martin-Taboada, Victor Castro-Alves, Rocio Vila-Bedmar, Ignacio González de Pablos, Daniel Duberg, Pilar Gomez et al. „Lipidomic and Metabolomic Signature of Progression of Chronic Kidney Disease in Patients with Severe Obesity“. Metabolites 11, Nr. 12 (03.12.2021): 836. http://dx.doi.org/10.3390/metabo11120836.

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Severe obesity is a major risk for chronic kidney disease (CKD). Early detection and careful monitoring of renal function are critical for the prevention of CKD during obesity, since biopsies are not performed in patients with CKD and diagnosis is dependent on the assessment of clinical parameters. To explore whether distinct lipid and metabolic signatures in obesity may signify early stages of pathogenesis toward CKD, liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-high resolution accurate mass-mass spectrometry (GC-HRAM-MS) analyses were performed in the serum and the urine of severely obese patients with and without CKD. Moreover, the impact of bariatric surgery (BS) in lipid and metabolic signature was also studied, through LC-MS and GC-HRAM-MS analyses in the serum and urine of patients with severe obesity and CKD before and after undergoing BS. Regarding patients with severe obesity and CKD compared to severely obese patients without CKD, serum lipidome analysis revealed significant differences in lipid signature. Furthermore, serum metabolomics profile revealed significant changes in specific amino acids, with isoleucine and tyrosine, increased in CKD patients compared with patients without CKD. LC-MS and GC-HRAM-MS analysis in serum of patients with severe obesity and CKD after BS showed downregulation of levels of triglycerides (TGs) and diglycerides (DGs) as well as a decrease in branched-chain amino acid (BCAA), lysine, threonine, proline, and serine. In addition, BS removed most of the correlations in CKD patients against biochemical parameters related to kidney dysfunction. Concerning urine analysis, hippuric acid, valine and glutamine were significantly decreased in urine from CKD patients after surgery. Interestingly, bariatric surgery did not restore all the lipid species, some of them decreased, hence drawing attention to them as potential targets for early diagnosis or therapeutic intervention. Results obtained in this study would justify the use of comprehensive mass spectrometry-based lipidomics to measure other lipids aside from conventional lipid profiles and to validate possible early markers of risk of CKD in patients with severe obesity.
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Ramanathan, Lakshmi, und Helen Shen. „LC–TOF–MS methods to quantify siRNAs and major metabolite in plasma, urine and tissues“. Bioanalysis 11, Nr. 21 (November 2019): 1983–92. http://dx.doi.org/10.4155/bio-2019-0134.

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There are a few different bioanalytical approaches that have been used for the quantification of siRNA in biological matrices, such as S1 nuclease protection ‘cutting ELISA’, fluorescent probe hybridization HPLC, HPLC UV, LC–MS/high-resolution accurate-mass (HRAM) and LC–MS/MS. We have developed and validated plasma assays for several oligonucleotides such as GalNAc-conjugated siRNA, using uHPLC and high-resolution mass spectrometer by TOF detection. Although the molecular weights are in the range of 7000–9000, we were able to meet the same assay acceptance criteria as for the small molecules based on regulatory bioanalytical method validation guidance. The antisense strand and the sense strand can both be monitored. The method was also used in the tissue lysate matrices without a full validation.
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Yao, Jiaxu, Jinrui Zhu, Minjie Zhao, Li Zhou und Eric Marchioni. „Untargeted Lipidomics Method for the Discrimination of Five Crab Species by Ultra-High-Performance Liquid Chromatography High-Resolution Mass Spectrometry Combined with Chemometrics“. Molecules 28, Nr. 9 (22.04.2023): 3653. http://dx.doi.org/10.3390/molecules28093653.

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In this study, ultra-high-performance liquid chromatography high-resolution accurate mass-mass spectrometry (UHPLC-HRAM/MS) was applied to characterize the lipid profiles of five crab species. A total of 203 lipid molecular species in muscle tissue and 176 in edible viscera were quantified. The results indicate that Cancer pagurus contained high levels of lipids with a docosahexaenoic acid (DHA) and eicosapntemacnioc acid (EPA) structure in the muscle tissue and edible viscera. A partial least squares discriminant analysis (PLS-DA) showed that PE 16:0/22:6, PE P-18:0/20:5, PA 16:0/22:6 and PC 16:0/16:1 could be used as potential biomarkers to discriminate the five kinds of crabs. In addition, some lipids, such as PE 18:0/20:5, PC 16:0/16:1, PE P-18:0/22:6 and SM 12:1;2O/20:0, could be used as characteristic molecules to distinguish between Cancer magister and Cancer pagurus, which are similar in appearance. This study provides a new perspective on discriminating crab species from MS-based lipidomics.
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Byrdwell, William C., und Hari Kiran Kotapati. „Multi-Dimensional Liquid Chromatography of Pulse Triacylglycerols with Triple Parallel Mass Spectrometry“. Separations 10, Nr. 12 (05.12.2023): 594. http://dx.doi.org/10.3390/separations10120594.

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We analyzed ten pulses (the dried seeds of legumes), i.e., baby lima beans, black beans, black-eyed peas, butter beans, cranberry beans, garbanzo beans, green split peas, lentils, navy beans, and pinto beans, using three-dimensional liquid chromatography (3D-LC) with parallel second dimensions, LC × (LC + LC). We combined non-aqueous reversed-phase (NARP) chromatography as the first dimension separation, 1D, with argentation UHPLC for separation based on degree and location of unsaturation in the first second dimension, 2D(1), and multi-cycle NARP-UHPLC in the second second dimension, 2D(2). Pulses contained 1.9% to 2.7% lipids, except garbanzo beans, which contained 6.2% lipids. High-resolution, accurate-mass (HRAM) orbitrap mass spectrometry (MS) was used to perform lipidomic analysis of the 2D(2) and percent relative quantification, showing that the most abundant average triacylglycerol (TAG) molecular species across all pulses were PLL at 10.67% and PLLn at 10.45%. Common beans (Phaseolus vulgaris) were clustered together using principal component analysis (PCA), showing the highest levels of linolenic acid, C18:3, in molecular species such as PLnLn, LLnLn, and OLLn, with palmitic (P), C16:0, linoleic (L), 18:2, linolenic (Ln), 18:3, and oleic (O), 18:1, FAs. Calibration curves derived from interweaved sets of regioisomer standards allowed the absolute quantification of 1,2- and 1,3-regioisomers for a subset of TAGs.
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Moore, Eli K., Ellen C. Hopmans, W. Irene C. Rijpstra, Laura Villanueva, Svetlana N. Dedysh, Irina S. Kulichevskaya, Hans Wienk, Frans Schoutsen und Jaap S. Sinninghe Damsté. „Novel Mono-, Di-, and Trimethylornithine Membrane Lipids in Northern Wetland Planctomycetes“. Applied and Environmental Microbiology 79, Nr. 22 (30.08.2013): 6874–84. http://dx.doi.org/10.1128/aem.02169-13.

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ABSTRACTNorthern peatlands represent a significant global carbon store and commonly originate fromSphagnummoss-dominated wetlands. These ombrotrophic ecosystems are rain fed, resulting in nutrient-poor, acidic conditions. Members of the bacterial phylumPlanctomycetesare highly abundant and appear to play an important role in the decomposition ofSphagnum-derived litter in these ecosystems. High-performance liquid chromatography coupled to high-resolution accurate-mass mass spectrometry (HPLC-HRAM/MS) analysis of lipid extracts of four isolated planctomycetes from wetlands of European north Russia revealed novel ornithine membrane lipids (OLs) that are mono-, di-, and trimethylated at the ε-nitrogen position of the ornithine head group. Nuclear magnetic resonance (NMR) analysis of the isolated trimethylornithine lipid confirmed the structural identification. Similar fatty acid distributions between mono-, di-, and trimethylornithine lipids suggest that the three lipid classes are biosynthetically linked, as in the sequential methylation of the terminal nitrogen in phosphatidylethanolamine to produce phosphatidylcholine. The mono-, di-, and trimethylornithine lipids described here represent the first report of methylation of the ornithine head groups in biological membranes. Various bacteria are known to produce OLs under phosphorus limitation or fatty-acid-hydroxylated OLs under thermal or acid stress. The sequential methylation of OLs, leading to a charged choline-like moiety in the trimethylornithine lipid head group, may be an adaptation to provide membrane stability under acidic conditions without the use of scarce phosphate in nutrient-poor ombrotrophic wetlands.
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Abu-Reidah, Ibrahim M., Amber L. Critch, Charles F. Manful, Amanda Rajakaruna, Natalia P. Vidal, Thu H. Pham, Mumtaz Cheema und Raymond Thomas. „Effects of pH and Temperature on Water under Pressurized Conditions in the Extraction of Nutraceuticals from Chaga (Inonotus obliquus) Mushroom“. Antioxidants 10, Nr. 8 (23.08.2021): 1322. http://dx.doi.org/10.3390/antiox10081322.

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Currently, there is increased interest in finding appropriate food-grade green extraction systems capable of extracting these bioactive compounds from dietary mushrooms for applications in various food, pharmacological, or nutraceutical formulations. Herein, we evaluated a modified Swiss water process (SWP) method using alkaline and acidic pH at low and high temperature under pressurized conditions as a suitable green food grade solvent to obtained extracts enriched with myco-nutrients (dietary phenolics, total antioxidants (TAA), vitamins, and minerals) from Chaga. Ultra-high performance liquid chromatography coupled to high resolution accurate mass tandem mass spectrometry (UHPLC-HRAMS-MS/MS) was used to assess the phenolic compounds and vitamin levels in the extracts, while inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the mineral contents. Over 20 phenolic compounds were quantitatively evaluated in the extracts and the highest total phenolic content (TPC) and total antioxidant activity (TAA) was observed at pH 11.5 at 100 °C. The most abundant phenolic compounds present in Chaga extracts included phenolic acids such as protocatechuic acid 4-glucoside (0.7–1.08 µg/mL), syringic acid (0.62–1.18 µg/mL), and myricetin (0.68–1.3 µg/mL). Vitamins are being reported for the first time in Chaga. Not only, a strong correlation was found for TPC with TAA (r-0.8, <0.0001), but also, with individual phenolics (i.e., Salicylic acid), lipophilic antioxidant activity (LAA), and total antioxidant minerals (TAM). pH 2.5 at 100 °C treatment shows superior effects in extracting the B vitamins whereas pH 2.5 at 60 and 100 °C treatments were outstanding for extraction of total fat-soluble vitamins. Vitamin E content was the highest for the fat-soluble vitamins in the Chaga extract under acidic pH (2.5) and high temp. (100 °C) and ranges between 50 to 175 µg/100 g Chaga. Antioxidant minerals ranged from 85.94 µg/g (pH7 at 100 °C) to 113.86 µg/g DW (pH2.5 at 100 °C). High temperature 100 °C and a pH of 2.5 or 9.5. The treatment of pH 11.5 at 100 °C was the most useful for recovering phenolics and antioxidants from Chaga including several phenolic compounds reported for the first time in Chaga. SWP is being proposed herein for the first time as a novel, green food-grade solvent system for the extraction of myco-nutrients from Chaga and have potential applications as a suitable approach to extract nutrients from other matrices. Chaga extracts enriched with bioactive myconutrients and antioxidants may be suitable for further use or applications in the food and nutraceutical industries.
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Cawley, Adam, Daniel Pasin, Namuun Ganbat, Laura Ennis, Corrine Smart, Candace Greer, John Keledjian, Shanlin Fu und Alex Chen. „The potential for complementary targeted/non-targeted screening of novel psychoactive substances in equine urine using liquid chromatography-high resolution accurate mass spectrometry“. Analytical Methods 8, Nr. 8 (2016): 1789–97. http://dx.doi.org/10.1039/c6ay00156d.

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10

Smith, Richard D. „Advanced Mass Spectrometric Methods for the Rapid and Quantitative Characterization of Proteomes“. Comparative and Functional Genomics 3, Nr. 2 (2002): 143–50. http://dx.doi.org/10.1002/cfg.159.

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Progress is reviewed towards the development of a global strategy that aims to extend the sensitivity, dynamic range, comprehensiveness and throughput of proteomic measurements based upon the use of high performance separations and mass spectrometry. The approach uses high accuracy mass measurements from Fourier transform ion cyclotron resonance mass spectrometry (FTICR) to validate peptide ‘accurate mass tags’ (AMTs) produced by global protein enzymatic digestions for a specific organism, tissue or cell type from ‘potential mass tags’ tentatively identified using conventional tandem mass spectrometry (MS/MS). This provides the basis for subsequent measurements without the need for MS/ MS. High resolution capillary liquid chromatography separations combined with high sensitivity, and high resolution accurate FTICR measurements are shown to be capable of characterizing peptide mixtures of more than105components. The strategy has been initially demonstrated using the microorganismsSaccharomyces cerevisiaeandDeinococcus radiodurans.Advantages of the approach include the high confidence of protein identification, its broad proteome coverage, high sensitivity, and the capability for stableisotope labeling methods for precise relative protein abundance measurements.Abbreviations: LC, liquid chromatography; FTICR, Fourier transform ion cyclotron resonance; AMT, accurate mass tag; PMT, potential mass tag; MMA, mass measurement accuracy; MS, mass spectrometry; MS/MS, tandem mass spectrometry; ppm, parts per million.
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Cradic, Kendall W., Paula M. Ladwig, Ann L. Rivard, Waddah Katrangi, Karl Florian Wintgens und Maria A. V. Willrich. „Vedolizumab quantitation using high-resolution accurate mass-mass spectrometry middle-up protein subunit: method validation“. Clinical Chemistry and Laboratory Medicine (CCLM) 58, Nr. 6 (25.06.2020): 864–72. http://dx.doi.org/10.1515/cclm-2019-0862.

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AbstractBackgroundWhile quantitation methods for small-molecule and tryptic peptide bottom-up mass spectrometry (MS) have been well defined, quantitation methods for top-down or middle-up MS approaches have not been as well defined. Therapeutic monoclonal antibodies (t-mAbs) are a group of proteins that can be used to both demonstrate the advantages of top-down or middle-up detection methods over classic tryptic peptide bottom-up along with the growing need for robust quantitation strategies/software for these top-down or middle-up methods. Bottom-up proteolytic digest methods for the t-mAbs tend to suffer from challenges such as limited peptide selection due to potential interference from the polyclonal immunoglobulin background, complicated workflows, and inadequate sensitivity and specificity without laborious purification steps, and therefore have prompted the search for new detection and quantitation methods. Time-of-flight along with Orbitrap MS have recently evolved from the research and/or pharmaceutical setting into the clinical laboratory. With their superior mass measurement accuracy, resolution and scanning speeds, these are ideal platforms for top-down or middle-up characterization and quantitation.MethodsWe demonstrate a validated, robust, middle-up protein subunit detection and quantitation method for the IgG1 t-mAb, vedolizumab (VEDO), which takes advantage of the high resolution of the Orbitrap MS detection and quantitation software to increase specificity.ResultsValidated performance characteristics met pre-defined acceptance criteria with simple workflows and rapid turnaround times: characteristics necessary for implementation into a high-volume clinical MS laboratory.ConclusionsWhile the extraction method can easily be used with other IgG1 t-mAbs, the detection and quantitation method may become an option for measurement of other proteins.
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Lim, Ameline, Cheka Kehelpannala, Fatemeh Vafaee, Forrest Koch, Dana Pascovici, Desmond Li, Kerry Heffernan, Gillian Lamoury, Amani Batarseh und Bruce Mann. „Abstract PO4-07-02: Development of an Artificial Intelligence-based breast cancer detection model using Plasma Lipidomic Signature“. Cancer Research 84, Nr. 9_Supplement (02.05.2024): PO4–07–02—PO4–07–02. http://dx.doi.org/10.1158/1538-7445.sabcs23-po4-07-02.

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Abstract Background: Mammography is the current diagnostic standard for breast cancer screening and monitoring. However, accessibility challenges, accuracy issues and patient discomfort all contribute to reduced patient compliance and utilization, resulting in a need for more effective diagnostic tools. An artificial intelligence (AI)-based lipidomic blood test may add significant value to early breast cancer detection rate and improve outcomes for patients. We have previously reported a series of lipidomic studies (n=793) and derived a lipid signature from plasma-enriched extracellular vesicles (EVs) that effectively distinguished people with localized breast cancer from cancer-free controls. Here we report the development of a breast cancer detection AI model from lipidomic data assessed directly using plasma samples. Methods: Lipids in both EVs and plasma collected from fasted breast cancer and control blood samples (n=256) were extracted and analysed by liquid chromatography-high resolution mass spectrometry (LC-HRAM-MS). Over 400 manually curated lipids were quantified. A bootstrapped analysis using Boruta, a robust and statistically rigorous feature selection algorithm based on random forest feature importance, was employed to identify cancer discriminatory lipid signatures in EV and plasma lipidomes consistently selected across 2000 bootstrap samples. The resulting lipid signature was then used to train an ensemble of 18 distinct machine learning models for cancer status prediction using a majority vote to aggregate the individual predictions. Model performance and variability were assessed over 2000 iterations of leave-group-out cross-validation (LGOCV) using an 80/20 train-test split. Average patient-level predictions across LGOCV iterations were recorded for both EV-and plasma-derived models and the two modalities were compared using an exact paired samples test (McNemar’s test). Results: Both the EV- and plasma-derived lipid signatures performed well in distinguishing breast cancer samples from controls. The development of a bioinformatics AI pipeline enabled the creation of a robust ensemble model achieving an F1 score of 0.89 in plasma with LGOCV. The final plasma ensemble predictive performance of 86.1% (±4.5%) in accuracy, 91.4% (±5.4%) in sensitivity, and 78.7% (±8.6%) specificity was achieved, which is comparable to that of EV (accuracy: 86.1±4.4%, sensitivity: 90.4±5.3%, specificity: 80.2±8.7%). Paired samples analysis using McNemar’s test indicated no significant differences between models trained on EV- and plasma-derived lipid signatures in either the sensitivity (p=0.65), specificity (p=0.49), or accuracy (p=0.42). Conclusion: The initial study demonstrated the high performance of a plasma-enriched extracellular vesicle-derived lipid biomarker signature for early breast cancer detection. Direct assessment of the lipidomic signature from plasma showed promise in simplifying the test. Assessing plasma directly offered advantages in terms of scalability, higher throughput, and ease of implementation. Further verification of the lipid signature in an upcoming study involving 500 plasma samples is planned. Ongoing studies will further optimize the plasma lipidomic signature and strengthen our AI pipeline. These findings support the potential clinical application of AI-based lipidomic profiling as a blood-based screening tool for breast cancer detection. Citation Format: Ameline Lim, Cheka Kehelpannala, Fatemeh Vafaee, Forrest Koch, Dana Pascovici, Desmond Li, Kerry Heffernan, Gillian Lamoury, Amani Batarseh, Bruce Mann. Development of an Artificial Intelligence-based breast cancer detection model using Plasma Lipidomic Signature [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-07-02.
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Nehmeh, Bilal, Fatima Haydous und Elias Akoury. „Mass calibrants for positive chemical ionization-high resolution mass spectrometry (CI-HRMS) for the identification of unknown compounds using accurate mass measurements“. RSC Advances 13, Nr. 20 (2023): 14001–9. http://dx.doi.org/10.1039/d3ra01977b.

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14

Nuñez, Alberto, Yelena Sapozhnikova und Steven Lehotay. „Characterization of MS/MS Product Ions for the Differentiation of Structurally Isomeric Pesticides by High-Resolution Mass Spectrometry“. Toxics 6, Nr. 4 (02.10.2018): 59. http://dx.doi.org/10.3390/toxics6040059.

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Structural isomeric pesticides are used in agriculture and may be challenging to differentiate for accurate identification in pesticide monitoring programs. Due to structural similarity, isomeric pesticides are difficult to separate chromatographically, and thus, their accurate identification may rely solely on mass spectrometric analysis (MS). In this study, we challenged the ability of high-resolution quadrupole-orbitrap (Q-Orbitrap) mass spectrometry to produce and evaluate the tandem mass spectrometry (MS/MS) product ions for the selected five pairs of isomeric pesticides from different classes: Pebulate and vernolate, methiocarb and ethiofencarb, uniconazole and cyproconazole, sebuthylazine and terbuthylazine, and orbencarb and thiobencarb. The use of Q-Orbitrap instrument with a mass error <3 ppm allowed proposed elucidation of the product ion structures with consideration of the ion formulae, data interpretation, and literature searches. Product ions unique to pebulate, vernolate, methiocarb, ethiofencarb, and uniconazole were observed. Elucidation of the observed MS/MS product ion structures was conducted, and the fragmentation pathways were proposed. This information is valuable to increase selectivity in MS/MS analysis and differentiate isomeric pesticides, and thereby reduce the rates of false positives in pesticide monitoring programs.
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Vanhee, Celine, Sophia Barhdadi, Angélique Kamugisha, Tanika Van Mulders, Kevin Vanbrusselen, Marie Willocx und Eric Deconinck. „The Development and Validation of a Targeted LC-HRAM-MS/MS Methodology to Separate and Quantify p-Synephrine and m-Synephrine in Dietary Supplements and Herbal Preparations“. Separations 10, Nr. 8 (09.08.2023): 444. http://dx.doi.org/10.3390/separations10080444.

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Dietary supplements containing Citrus aurantium or p-synephrine remain very popular in Europe and the United States of America (USA). They are primarily sold as weight loss enhancers, although their efficacy and the safety are still under scrutiny. To this end, several countries have set maximum threshold levels of p-synephrine that are permitted in dietary supplements. Moreover, there have also been reports of possible chemical adulteration of these supplements with the synthetic positional isomer, m-synephrine, known to be used as a medicinal product. Therefore, it is pivotal for regulatory agencies to be able to discriminate between the two positional isomers and also quantify the amount of each when encountered in dietary supplements. Here, we present the development and the validation of a simple and fast “dilute and shoot” procedure, employing liquid chromatographic (LC) separation in combination with high-resolution accurate mass (HRAM) tandem mass spectroscopy (LC-HRAM-MS/MS) to separate these two isomers and subsequently quantify them. The quantification methodology has been validated using the “total error approach”, applying accuracy profiles, and is consequently compliant with ISO17025. Moreover, ten real-life samples, either purchased online or encountered by Belgian regulatory agencies, were analyzed using the described procedure. Startlingly, only one sample out of ten was compliant with Belgian legislation in terms of labeling, the presence of a batch number, expiration date and dosage (with a tolerated error of ±20%). Moreover, three samples also contained banned substances such as yohimbine and sibutramine.
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Nguyen, Don D., Veronika Saharuka, Vitaly Kovalev, Lachlan Stuart, Massimo Del Prete, Kinga Lubowiecka, René De Mot, Vittorio Venturi und Theodore Alexandrov. „Facilitating Imaging Mass Spectrometry of Microbial Specialized Metabolites with METASPACE“. Metabolites 11, Nr. 8 (23.07.2021): 477. http://dx.doi.org/10.3390/metabo11080477.

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Metabolite annotation from imaging mass spectrometry (imaging MS) data is a difficult undertaking that is extremely resource intensive. Here, we adapted METASPACE, cloud software for imaging MS metabolite annotation and data interpretation, to quickly annotate microbial specialized metabolites from high-resolution and high-mass accuracy imaging MS data. Compared with manual ion image and MS1 annotation, METASPACE is faster and, with the appropriate database, more accurate. We applied it to data from microbial colonies grown on agar containing 10 diverse bacterial species and showed that METASPACE was able to annotate 53 ions corresponding to 32 different microbial metabolites. This demonstrates METASPACE to be a useful tool to annotate the chemistry and metabolic exchange factors found in microbial interactions, thereby elucidating the functions of these molecules.
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Sawyer, William S., Neha Srikumar, Joseph Carver, Phillip Y. Chu, Amy Shen, Ankai Xu, Ambrose J. Williams et al. „High-throughput antibody screening from complex matrices using intact protein electrospray mass spectrometry“. Proceedings of the National Academy of Sciences 117, Nr. 18 (23.04.2020): 9851–56. http://dx.doi.org/10.1073/pnas.1917383117.

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Toward the goal of increasing the throughput of high-resolution mass characterization of intact antibodies, we developed a RapidFire–mass spectrometry (MS) assay using electrospray ionization. We achieved unprecedented screening throughput as fast as 15 s/sample, which is an order of magnitude improvement over conventional liquid chromatography (LC)-MS approaches. The screening enabled intact mass determination as accurate as 7 ppm with baseline resolution at the glycoform level for intact antibodies. We utilized this assay to characterize and perform relative quantitation of antibody species from 248 samples of 62 different cell line clones at four time points in 2 h using RapidFire–time-of-flight MS screening. The screening enabled selection of clones with the highest purity of bispecific antibody production and the results significantly correlated with conventional LC-MS results. In addition, analyzing antibodies from a complex plasma sample using affinity-RapidFire-MS was also demonstrated and qualified. In summary, the platform affords high-throughput analyses of antibodies, including bispecific antibodies and potential mispaired side products, in cell culture media, or other complex matrices.
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Ma, Xin. „Recent Advances in Mass Spectrometry-Based Structural Elucidation Techniques“. Molecules 27, Nr. 19 (30.09.2022): 6466. http://dx.doi.org/10.3390/molecules27196466.

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Mass spectrometry (MS) has become the central technique that is extensively used for the analysis of molecular structures of unknown compounds in the gas phase. It manipulates the molecules by converting them into ions using various ionization sources. With high-resolution MS, accurate molecular weights (MW) of the intact molecular ions can be measured so that they can be assigned a molecular formula with high confidence. Furthermore, the application of tandem MS has enabled detailed structural characterization by breaking the intact molecular ions and protonated or deprotonated molecules into key fragment ions. This approach is not only used for the structural elucidation of small molecules (MW < 2000 Da), but also crucial biopolymers such as proteins and polypeptides; therefore, MS has been extensively used in multiomics studies for revealing the structures and functions of important biomolecules and their interactions with each other. The high sensitivity of MS has enabled the analysis of low-level analytes in complex matrices. It is also a versatile technique that can be coupled with separation techniques, including chromatography and ion mobility, and many other analytical instruments such as NMR. In this review, we aim to focus on the technical advances of MS-based structural elucidation methods over the past five years, and provide an overview of their applications in complex mixture analysis. We hope this review can be of interest for a wide range of audiences who may not have extensive experience in MS-based techniques.
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Miyaguchi, Hajime. „Determination of sedative–hypnotics in human hair by micropulverized extraction and liquid chromatography/quadrupole-Orbitrap mass spectrometry“. Anal. Methods 6, Nr. 15 (2014): 5777–83. http://dx.doi.org/10.1039/c4ay00505h.

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20

Ding, Ying, Sitan Chen, Honglin Wang, Shanlei Li, Changyang Ma, Jinmei Wang und Lili Cui. „Identification of Secondary Metabolites in Flammulina velutipes by UPLC-Q-Exactive-Orbitrap MS“. Journal of Food Quality 2021 (26.07.2021): 1–8. http://dx.doi.org/10.1155/2021/4103952.

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Flammulina velutipes is the fourth largest edible fungus in China with high nutritional value. In this paper, ultrahigh-performance liquid chromatography tandem hybrid quadrupole-Orbitrap mass spectrometry (UPLC-Q-Exactive-Orbitrap MS) was used to identify the secondary metabolites of F. velutipes. The metabolites were identified by comparing the retention time, accurate molecular weight, and MS2 data with standard databases of mzVault and mzCloud (compound: 17,000+) and BGI high-resolution accurate mass plant metabolome database (plant metabolite: 2500+). Finally, 26 secondary metabolites were preliminarily identified, including flavonoids, phenylpropanoids, organic acids, and steroids.
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Racine, Marianne, Ammar Saleem und Frances R. Pick. „Metabolome Variation between Strains of Microcystis aeruginosa by Untargeted Mass Spectrometry“. Toxins 11, Nr. 12 (11.12.2019): 723. http://dx.doi.org/10.3390/toxins11120723.

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Cyanobacteria are notorious for their potential to produce hepatotoxic microcystins (MCs), but other bioactive compounds synthesized in the cells could be as toxic, and thus present interest for characterization. Ultra performance liquid chromatography and high-resolution accurate mass spectrometry (UPLC-QTOF-MS/MS) combined with untargeted analysis was used to compare the metabolomes of five different strains of the common bloom-forming cyanobacterium, Microcystis aeruginosa. Even in microcystin-producing strains, other classes of oligopeptides including cyanopeptolins, aeruginosins, and aerucyclamides, were often the more dominant compounds. The distinct and large variation between strains of the same widespread species highlights the need to characterize the metabolome of a larger number of cyanobacteria, especially as several metabolites other than microcystins can affect ecological and human health.
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Feith, André, Attila Teleki, Michaela Graf, Lorenzo Favilli und Ralf Takors. „HILIC-Enabled 13C Metabolomics Strategies: Comparing Quantitative Precision and Spectral Accuracy of QTOF High- and QQQ Low-Resolution Mass Spectrometry“. Metabolites 9, Nr. 4 (02.04.2019): 63. http://dx.doi.org/10.3390/metabo9040063.

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Dynamic 13C-tracer-based flux analyses of in vivo reaction networks still require a continuous development of advanced quantification methods applying state-of-the-art mass spectrometry platforms. Utilizing alkaline HILIC chromatography, we adapt strategies for a systematic quantification study in non- and 13C-labeled multicomponent endogenous Corynebacterium glutamicum extracts by LC-QTOF high resolution (HRMS) and LC-QQQ tandem mass spectrometry (MS/MS). Without prior derivatization, a representative cross-section of 17 central carbon and anabolic key intermediates were analyzed with high selectivity and sensitivity under optimized ESI-MS settings. In column detection limits for the absolute quantification range were between 6.8–304.7 (QQQ) and 28.7–881.5 fmol (QTOF) with comparable linearities (3–5 orders of magnitude) and enhanced precision using QQQ-MRM detection. Tailor-made preparations of uniformly (U)13C-labeled cultivation extracts for isotope dilution mass spectrometry enabled the accurate quantification in complex sample matrices and extended linearities without effect on method parameters. Furthermore, evaluation of metabolite-specific m+1-to-m+0 ratios (ISR1:0) in non-labeled extracts exhibited sufficient methodical spectral accuracies with mean deviations of 3.89 ± 3.54% (QTOF) and 4.01 ± 3.01% (QQQ). Based on the excellent HILIC performance, conformity analysis of time-resolved isotopic enrichments in 13C-tracer experiments revealed sufficient spectral accuracy for QQQ-SIM detection. However, only QTOF-HRMS ensures determination of the full isotopologue space in complex matrices without mass interferences.
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Revelou, Panagiota-Kyriaki, Maroula G. Kokotou und Violetta Constantinou-Kokotou. „Identification of Auxin Metabolites in Brassicaceae by Ultra-Performance Liquid Chromatography Coupled with High-Resolution Mass Spectrometry“. Molecules 24, Nr. 14 (18.07.2019): 2615. http://dx.doi.org/10.3390/molecules24142615.

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Auxins are signaling molecules involved in multiple stages of plant growth and development. The levels of the most important auxin, indole-3-acetic acid (IAA), are regulated by the formation of amide and ester conjugates with amino acids and sugars. In this work, IAA and IAA amide conjugates with amino acids bearing a free carboxylic group or a methyl ester group, along with some selected IAA metabolites, were studied in positive and negative electrospray ionization (ESI) modes, utilizing high-resolution mass spectrometry (HRMS) as a tool for their structural analysis. HRMS/MS spectra revealed the fragmentation patterns that enable us to identify IAA metabolites in plant extracts from eight vegetables of the Brassicaceae family using a fast and reliable ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QToF-MS) method. The accurate m/z (mass to charge) ratio and abundance of the molecular and fragment ions of the studied compounds in plant extracts matched those obtained from commercially available or synthesized compounds and confirmed the presence of IAA metabolites.
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Tanna, Sangeeta, John Ogwu und Graham Lawson. „Hyphenated mass spectrometry techniques for assessing medication adherence: advantages, challenges, clinical applications and future perspectives“. Clinical Chemistry and Laboratory Medicine (CCLM) 58, Nr. 5 (28.04.2020): 643–63. http://dx.doi.org/10.1515/cclm-2019-0820.

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AbstractNonadherence to prescribed pharmacotherapy is an understated public health problem globally and is costing many patients their chance to return to good health and healthcare systems billions. Clinicians need an accurate assessment of adherence to medications to aid the clinical decision-making process in the event of poor patient progress and to maximise the patient health outcomes from the drug therapies prescribed. An overview of indirect and direct methods used to measure medication adherence is presented, highlighting the potential for accurate measuring of drugs in biological samples using hyphenated mass spectrometry (MS) techniques to provide healthcare professionals with a reliable evidence base for clinical decision making. In this review we summarise published applications of hyphenated MS techniques for a diverse range of clinical areas demonstrating the rise in the use of such direct methods for assessing medication adherence. Although liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods using plasma, serum and urine samples are the most popular, in recent years increased attention has been given to liquid chromatography high-resolution mass spectrometry (LC-HRMS) methods and alternative biosample matrices including hair, saliva and blood microsamples. The advantages and challenges of using hyphenated MS techniques to address this healthcare problem are also discussed alongside future perspectives.
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Loh, Zhi Hung, Natasha L. Hungerford, Diane Ouwerkerk, Athol V. Klieve und Mary T. Fletcher. „Identification of Acid Hydrolysis Metabolites of the Pimelea Toxin Simplexin for Targeted UPLC-MS/MS Analysis“. Toxins 15, Nr. 9 (05.09.2023): 551. http://dx.doi.org/10.3390/toxins15090551.

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Pimelea poisoning of cattle is a unique Australian toxic condition caused by the daphnane orthoester simplexin present in native Pimelea pasture plants. Rumen microorganisms have been proposed to metabolise simplexin by enzymatic reactions, likely at the orthoester and epoxide moieties of simplexin, but a metabolic pathway has not been confirmed. This study aimed to investigate this metabolic pathway through the analysis of putative simplexin metabolites. Purified simplexin was hydrolysed with aqueous hydrochloric acid and sulfuric acid to produce target metabolites for UPLC-MS/MS analysis of fermentation fluid samples, bacterial isolate samples, and other biological samples. UPLC-MS/MS analysis identified predicted hydrolysed products from both acid hydrolysis procedures with MS breakdown of these putative products sharing high-resolution accurate mass (HRAM) fragmentation ions with simplexin. However, targeted UPLC-MS/MS analysis of the biological samples failed to detect the H2SO4 degradation products, suggesting that the rumen microorganisms were unable to produce similar simplexin degradation products at detectable levels, or that metabolites, once formed, were further metabolised. Overall, in vitro acid hydrolysis was able to hydrolyse simplexin at the orthoester and epoxide functionalities, but targeted UPLC-MS/MS analysis of biological samples did not detect any of the identified simplexin hydrolysis products.
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Saéz, Riquelme, Baer und Vallverdú-Queralt. „Phenolic Profile of Grape Canes: Novel Compounds Identified by LC-ESI-LTQ-Orbitrap-MS“. Molecules 24, Nr. 20 (18.10.2019): 3763. http://dx.doi.org/10.3390/molecules24203763.

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Grape canes (Vitis vinifera L.) are a viticulture industry by-product with an important content of secondary metabolites, mainly polyphenols with a broad spectrum of demonstrated health benefits. Grape canes, therefore, have considerable economic potential as a source of high-value phytochemicals. In this work, liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole-Orbitrap mass spectrometry (LC–LTQ-Orbitrap) was used for the comprehensive identification of polyphenolic compounds in grape canes. Identification of polyphenols was performed by comparing their retention times, accurate mass measured, and mass fragmentation patterns with those of reference substances or available data in the literature. A total of 75 compounds were identified, including phenolic acids, flavanols, flavonols, flavanonols, flavanones, and stilbenoids. The most abundant polyphenols were proanthocyanidins and stilbenoids and their oligomers. Moreover, the high-resolution mass spectrometry analysis revealed the occurrence of 17 polyphenols never described before in grape canes, thereby providing a more complete polyphenolic profile of this potentially valuable by-product.
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Müller, Max A., Dhaka R. Bhandari und Bernhard Spengler. „Matrix-Free High-Resolution Atmospheric-Pressure SALDI Mass Spectrometry Imaging of Biological Samples Using Nanostructured DIUTHAME Membranes“. Metabolites 11, Nr. 9 (15.09.2021): 624. http://dx.doi.org/10.3390/metabo11090624.

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Applications of mass spectrometry imaging (MSI), especially matrix-assisted laser desorption/ionization (MALDI) in the life sciences are becoming increasingly focused on single cell analysis. With the latest instrumental developments, pixel sizes in the micrometer range can be obtained, leading to challenges in matrix application, where imperfections or inhomogeneities in the matrix layer can lead to misinterpretation of MS images. Thereby, the application of premanufactured, homogeneous ionization-assisting devices is a promising approach. Tissue sections were investigated using a matrix-free imaging technique (Desorption Ionization Using Through-Hole Alumina Membrane, DIUTHAME) based on premanufactured nanostructured membranes to be deposited on top of a tissue section, in comparison to the spray-coating of an organic matrix in a MALDI MSI approach. Atmospheric pressure MALDI MSI ion sources were coupled to orbital trapping mass spectrometers. MS signals obtained by the different ionization techniques were annotated using accurate-mass-based database research. Compared to MALDI MSI, DIUTHAME MS images captivated with higher signal homogeneities, higher contrast and reduced background signals, while signal intensities were reduced by about one order of magnitude, independent of analyte class. DIUTHAME membranes, being applicable only on tissue sections thicker than 50 µm, were successfully used for mammal, insect and plant tissue with a high lateral resolution down to 5 µm.
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Turnipseed, Sherri B., Jack J. Lohne und Joe O. Boison. „Review: Application of High Resolution Mass Spectrometry to Monitor Veterinary Drug Residues in Aquacultured Products“. Journal of AOAC INTERNATIONAL 98, Nr. 3 (01.05.2015): 550–58. http://dx.doi.org/10.5740/jaoacint.14-265.

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Abstract High resolution MS (HRMS) instruments provide accurate mass measurements. With HRMS, virtually an unlimited number of compounds can be analyzed simultaneously because full-scan data are collected, rather than preselected ion transitions corresponding to specific compounds. This enables the development of methods that can monitor for a wide scope of residues and contaminants in aquacultured fish and shellfish including antibiotics, metabolites, and emerging contaminants. Applications of HRMS to the analysis of veterinary drug residues in aquacultured products are summarized in this review including methods for screening, quantifying, and identifying drug residues in these matrixes. The use of targeted, semi-targeted, and nontargeted analysis of HRMS data and the implications to the global aquaculture industry are also reviewed.
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Mahale, Vishal, Ajeet Singh, Gayatri S. Phadke, Avinash D. Ghanate, Dasharath P. Oulkar, Kaushik Banerjee und Venkateswarlu Panchagnula. „Determination of Triazines and Triazoles in Grapes Using Atmospheric Pressure Matrix-Assisted Laser Desorption/Ionization High-Resolution Mass Spectrometry“. Journal of AOAC INTERNATIONAL 100, Nr. 3 (01.05.2017): 640–46. http://dx.doi.org/10.5740/jaoacint.17-0047.

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Abstract A chromatography-free atmospheric pressure matrix-assisted laser desorption/ionization high-resolution massspectrometry (AP-MALDI HRMS) method is described for the simultaneous and quantitative detection of triazines and triazoles in grapes. The analytes were detected reproducibly with high mass accuracy (mass error within 5 ppm) and further confirmed by collision-induced dissociation fragmentation in tandem MS. The LODs and LOQs forall the analytes were found to be in the nanogram per gram level (15–20 ng/g LOQ). Internal standard–normalized high-resolution accurate mass–extracted (HR-AM) peak intensities of the detected ions were used to generate the concentration response curves. Linearity (with R2 values around 0.99) was obtained for these curves within a concentration range of 20–200 ng/g of the individual analytes. The accuracy and precision of the method were further established using QC samples. Validation and performancecomparison of the AP-MALDI HRMS method with an existing standard method using LC with triple quadrupole MS was carried out (evaluating sensitivity, accuracy, precision, and analysis time) using 20 table-grape field samples after QuEChERS extraction.
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Ashrafkhani, Behnam, Chris Chambers, Michael Wieser, Robert Thompson und A. A. Kwiatkowski. „Optimizing Ion Optical Design for Laser Ablation Source in Mass Spectrometry“. Journal of Physics: Conference Series 2743, Nr. 1 (01.05.2024): 012086. http://dx.doi.org/10.1088/1742-6596/2743/1/012086.

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Abstract The study focuses on optimizing a Laser Ablation Source (LAS) for use in mass spectrometry, particularly aiming to enhance transmission of ions and and determination of isotopic compositions in diverse matrices at TRIUMF’s Ion Trap for Atomic and Nuclear Science (TITAN). Critical variables affecting mass spectrometer resolution, such as ion kinetic energy distribution and ion transport are optimized through LAS. The paper explores the importance of consistent initial conditions, ion transport efficiency, and ion capture for accurate and reproducible measurements. Using SIMION software, we optimized ion optical design to tackle challenges like collimating ions travelling off-axis and mass filtering. A significant part of the study is dedicated to ion optic design to enable low abundance measurement of ions of interest (e.g., 10 ions of interest out of 1014 total ions). Techniques like high voltage switching and beam shaping were explored, and the final design aims for high transport efficiency and a 4 mm effective target scan area with maximum transport efficiency. The integration of LAS with a Multiple-Reflection Time-Of-Flight Mass Spectrometer (MR-TOF-MS) is expected to yield an analytical tool with high spatial resolution and transport efficiency for isotope abundance measurement.
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Wang, Jian, Wendy Cheung und Willis Chow. „Ultra-High Performance Liquid Chromatography/Electrospray Ionization-Tandem Mass Spectrometry Determination of 151 Pesticides in Soybeans and Pulses“. Journal of AOAC INTERNATIONAL 96, Nr. 5 (01.09.2013): 1114–33. http://dx.doi.org/10.5740/jaoacint.12-465.

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Abstract This paper presents the application of ultra-high performance LC (UHPLC) and MS for the determination of 151 pesticides in soybeans and pulses. A core-shell particle (2.6 μm particle size) column and a fully porous sub-2 μm (1.7 μm particle size) column showed comparable performance in chromatographic resolution and separation, increasing selectivity, and reducing analysis time. UHPLC was coupled with either a triple quadrupole mass analyzer (MS/MS) or a quadrupole Orbitrap (namely Orbital trap) mass spectrometer (Q-Orbitrap MS), which possesses fast data acquisition capability. Both configurations yielded analytical run times of ≤14 min. Soybean and pulse samples were analyzed and quantitated for pesticide residues using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) procedure, UHPLC/electrospray ionization (ESI)-MS/MS, and matrix-matched standard calibration curves (in an analytical range of 5–500 μg/kg) with isotopically-labeled standards or a chemical analog as internal standards. The method performance parameters that included overall recovery, intermediate precision, and measurement uncertainty were evaluated according to a nested design experiment. Approximately 89% of the pesticides studied had recoveries between 81 and 110%; 95%, had intermediate precision ≤20%; and 93% showed measurement uncertainty ≤40%. From a pilot study of 100 samples, eight tested positive by UHPLC/ESI-MS/MS for carbendazim, methomyl, or imidacloprid. These pesticides were further confirmed using UHPLC/ESI-Q-Orbitrap MS based on accurate mass measurement with mass error ≤5 ppm.
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Jensen, de Boevre, Preußke, de Saeger, Birr, Verreet und Sönnichsen. „Evaluation of High-Resolution Mass Spectrometry for the Quantitative Analysis of Mycotoxins in Complex Feed Matrices“. Toxins 11, Nr. 9 (12.09.2019): 531. http://dx.doi.org/10.3390/toxins11090531.

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The selective and sensitive analysis of mycotoxins in highly complex feed matrices is a great challenge. In this study, the suitability of OrbitrapTM-based high-resolution mass spectrometry (HRMS) for routine mycotoxin analysis in complex feeds was demonstrated by the successful validation of a full MS/data-dependent MS/MS acquisition method for the quantitative determination of eight Fusarium mycotoxins in forage maize and maize silage according to the Commission Decision 2002/657/EC. The required resolving power for accurate mass assignments (<5 ppm) was determined as 35,000 full width at half maximum (FWHM) and 70,000 FWHM for forage maize and maize silage, respectively. The recovery (RA), intra-day precision (RSDr), and inter-day precision (RSDR) of measurements were in the range of 94 to 108%, 2 to 16%, and 2 to 12%, whereas the decision limit (CCα) and the detection capability (CCβ) varied from 11 to 88 µg/kg and 20 to 141 µg/kg, respectively. A set of naturally contaminated forage maize and maize silage samples collected in northern Germany in 2017 was analyzed to confirm the applicability of the HRMS method to real samples. At least four Fusarium mycotoxins were quantified in each sample, highlighting the frequent co-occurrence of mycotoxins in feed.
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Melnyk, Lisa Jo, Jeffrey N. Morgan, Reshan Fernando, Edo D. Pellizzari und Olujide Akinbo. „Determination of Metals in Composite Diet Samples by Inductively Coupled Plasma-Mass Spectrometry“. Journal of AOAC INTERNATIONAL 86, Nr. 2 (01.03.2003): 439–48. http://dx.doi.org/10.1093/jaoac/86.2.439.

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Abstract A study was conducted to evaluate the applicability of inductively coupled plasma-mass spectrometry (ICP-MS) techniques for determination of metals in composite diets. Aluminum, cadmium, chromium, copper, lead, manganese, nickel, vanadium, and zinc were determined by this method. Atmospheric pressure microwave digestion was used to solubilize analytes in homogenized composite diet samples, and this procedure was followed by ICP-MS analysis. Recovery of certified elements from standard reference materials ranged from 92 to 119% with relative standard deviations (RSDs) of 0.4–1.9%. Recovery of elements from fortified composite diet samples ranged from 75 to 129% with RSDs of 0–11.3%. Limits of detection ranged from 1 to 1700 ng/g; high values were due to significant amounts of certain elements naturally present in composite diets. Results of this study demonstrate that low-resolution quadrupole-based ICP-MS provides precise and accurate measurements of the elements tested in composite diet samples.
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Hindle, Ralph, John Headley und Douglas G. Muench. „Pros and Cons of Separation, Fractionation and Cleanup for Enhancement of the Quantitative Analysis of Bitumen-Derived Organics in Process-Affected Waters—A Review“. Separations 10, Nr. 12 (24.11.2023): 583. http://dx.doi.org/10.3390/separations10120583.

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Oil sands process-affected water (OSPW) contains a diverse mixture of inorganic and organic compounds. Naphthenic acids (NAs) are a subset of the organic naphthenic acid fraction compounds (NAFCs) and are a major contributor of toxicity to aquatic species. Thousands of unique chemical formulae are measured in OSPW by accurate mass spectrometry and high-resolution mass spectrometry (MS) analysis of NAFCs. As no commercial reference standard is available to cover the range of compounds present in NAFCs, quantitation may best be referred to as “semi-quantitative” and is based on the responses of one or more model compounds. Negative mode electrospray ionization (ESI-) is often used for NAFC measurement but is prone to ion suppression in complex matrices. This review discusses aspects of off-line sample preparation techniques and liquid chromatography (LC) separations to help reduce ion suppression effects and improve the comparability of both inter-laboratory and intra-laboratory results. Alternative approaches to the analytical parameters discussed include extraction solvents, salt content of samples, extraction pH, off-line sample cleanup, on-line LC chromatography, calibration standards, MS ionization modes, NAFC compound classes, MS mass resolution, and the use of internal standards.
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Smith, David P., Tom W. Knapman, Iain Campuzano, Richard W. Malham, Joshua T. Berryman, Sheena E. Radford und Alison E. Ashcroft. „Deciphering Drift Time Measurements from Travelling Wave Ion Mobility Spectrometry-Mass Spectrometry Studies“. European Journal of Mass Spectrometry 15, Nr. 2 (April 2009): 113–30. http://dx.doi.org/10.1255/ejms.947.

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Detailed knowledge of the tertiary and quaternary structure of proteins and protein complexes is of immense importance in understanding their functionality. Similarly, variations in the conformational states of proteins form the underlying mechanisms behind many biomolecular processes, numerous of which are disease-related. Thus, the availability of reliable and accurate biophysical techniques that can provide detailed information concerning these issues is of paramount importance. Ion mobility spectrometry (IMS) coupled to mass spectrometry (MS) offers a unique opportunity to separate multi-component biomolecular entities and to measure the molecular mass and collision cross-section of individual components in a single, rapid (≤ 2 min) experiment, providing 3D-architectural information directly. Here we report a method of calibrating a commercially available electrospray ionisation (ESI)-travelling wave ion mobility spectrometry (TWIMS)–mass spectrometer using known cross-sectional areas determined for a range of biomolecules by conventional IMS-MS. Using this method of calibration, we have analysed a range of proteins of differing mass and 3D architecture in their native conformations by ESI-TWIMS-MS and found that the cross-sectional areas measured in this way compare extremely favourably with cross-sectional areas calculated using an in-house computing method based on Protein Data Bank NMR-derived co-ordinates. This not only provides a high degree of confidence in the calibration method, but also suggests that the gas phase ESI-TWIMS-MS measurements relate well to solution-based measurements derived from other biophysical techniques. In order to determine which instrumental parameters affect the ESI-TWIMS-MS cross-sectional area calibration, a systematic study of the parameters used to optimise TWIMS drift time separations has been carried out, observing the effect each parameter has on drift times and IMS resolution. Finally, the ESI-TWIMS-MS cross-sectional area calibration has been applied to the analysis of the amyloidogenic protein β2-microglobulin and measurements for three co-populated conformational families, present under denaturing conditions, have been made: the folded, partially unfolded and unfolded states.
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Klein, Joshua, Luis Carvalho und Joseph Zaia. „Application of network smoothing to glycan LC-MS profiling“. Bioinformatics 34, Nr. 20 (22.05.2018): 3511–18. http://dx.doi.org/10.1093/bioinformatics/bty397.

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Abstract Motivation Glycosylation is one of the most heterogeneous and complex protein post-translational modifications. Liquid chromatography coupled mass spectrometry (LC-MS) is a common high throughput method for analyzing complex biological samples. Accurate study of glycans require high resolution mass spectrometry. Mass spectrometry data contains intricate sub-structures that encode mass and abundance, requiring several transformations before it can be used to identify biological molecules, requiring automated tools to analyze samples in a high throughput setting. Existing tools for interpreting the resulting data do not take into account related glycans when evaluating individual observations, limiting their sensitivity. Results We developed an algorithm for assigning glycan compositions from LC-MS data by exploring biosynthetic network relationships among glycans. Our algorithm optimizes a set of likelihood scoring functions based on glycan chemical properties but uses network Laplacian regularization and optionally prior information about expected glycan families to smooth the likelihood and thus achieve a consistent and more representative solution. Our method was able to identify as many, or more glycan compositions compared to previous approaches, and demonstrated greater sensitivity with regularization. Our network definition was tailored to N-glycans but the method may be applied to glycomics data from other glycan families like O-glycans or heparan sulfate where the relationships between compositions can be expressed as a graph. Availability and implementation Built Executable http://www.bumc.bu.edu/msr/glycresoft/ and Source Code: https://github.com/BostonUniversityCBMS/glycresoft. Supplementary information Supplementary data are available at Bioinformatics online.
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Yang, Youyou, Zhuolin He, Lei Mu, Yunfeng Xie und Liang Wang. „Simultaneous Determination of 23 Mycotoxins in Broiler Tissues by Solid Phase Extraction UHPLC-Q/Orbitrap High Resolution Mass Spectrometry“. Separations 8, Nr. 12 (04.12.2021): 236. http://dx.doi.org/10.3390/separations8120236.

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Mycotoxins are a type of toxins harmful for not only animal but also human health. Cooccurrence of multi-mycotoxins could occur for food infected by several molds, producing multi-mycotoxins. It is necessary to develop corresponding determination methods, among which current mass spectrometry (MS) dominates. Currently, the accurate identification and quantitation of mycotoxins in complex matrices by MS with low resolution is still a challenge since false-positive results are typically obtained. Here, a method for the simultaneous determination of 23 mycotoxins in broiler tissues using ultra-high performance liquid chromatography-quadrupole/orbitrap HRMS was established. After the extraction by acetonitrile-water-formic acid (80:18:2, v/v/v), the purification by multifunctional purification solid phase extraction cartridges and the chromatographic separation on a C18 column, representative mycotoxins were determined by HRMS in full scan/data-dependent MS/MS acquisition mode. The quantitation was based on the external standard method. An MS/MS database of 23 mycotoxins was established to achieve qualitative screening and simultaneous quantification. Mycotoxins had a good linear relationship within a certain concentration range with correlation coefficients (r2) larger than 0.991 as well as the limit of quantitation of 1.80–300 μg/kg. The average recoveries at three different levels of low, medium and high fortification were 61–111% with relative standard deviations less than 13.5%. The method was fast, accurate, and suitable for the precise qualification of multiple mycotoxins in broiler tissues. 15 μg/kg zearalenone (ZEN) was detected in one liver sample among 30 samples from markets including chicken breast meat, liver, and gizzards. The result illustrated that the pollution of ZEN should not be neglected considering its harmful effect on the target organ of liver.
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Meng, Zhijuan, Qiang Li, Jianhan Cong, Yunxia Huang, Dong Wang, Canping Pan, Sufang Fan und Yan Zhang. „Rapid Screening of 350 Pesticide Residues in Vegetable and Fruit Juices by Multi-Plug Filtration Cleanup Method Combined with Gas Chromatography-Electrostatic Field Orbitrap High Resolution Mass Spectrometry“. Foods 10, Nr. 7 (16.07.2021): 1651. http://dx.doi.org/10.3390/foods10071651.

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A new method for screening pesticide residues in vegetable and fruit juices by the multi-plug filtration cleanup (m-PFC) method combined with gas chromatography-electrostatic field orbitrap high resolution mass spectrometry(GC-Orbitrap/MS) was developed. The samples were extracted with acetonitrile, purified with m-PFC and determined by GC-Orbitrap/MS. Qualitative analysis was confirmed by retention time, accurate molecular mass and quantitative analysis were performed with the matrix standard calibration. It could eliminate matrix interference effectively. Eight kinds of typical samples (orange juice, apple juice, grape juice, strawberry juice, celery juice, carrot juice, cucumber juice, tomato juice) were evaluated. The linear ranges of the 350 pesticides were from 5 to 500 μg/kg, with good correlation coefficients greater than 0.990. The limits of detection (LODs) were 0.3–3.0 μg/kg and the limits of quantification (LOQs) were 1.0–10.0 μg/kg. The average recoveries at three spiked levels of 10, 100, 200 μg/kg were in the range of 72.8–122.4%, with relative standard deviations (RSDs) of 2.0–10.8%. The method has effectively improved the determination efficiency of pesticide residue screening by high-resolution mass spectrometry in vegetable and fruit juices.
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Koelmel, Jeremy P., Xiangdong Li, Sarah M. Stow, Mark J. Sartain, Adithya Murali, Robin Kemperman, Hiroshi Tsugawa et al. „Lipid Annotator: Towards Accurate Annotation in Non-Targeted Liquid Chromatography High-Resolution Tandem Mass Spectrometry (LC-HRMS/MS) Lipidomics Using a Rapid and User-Friendly Software“. Metabolites 10, Nr. 3 (12.03.2020): 101. http://dx.doi.org/10.3390/metabo10030101.

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Lipidomics has great promise in various applications; however, a major bottleneck in lipidomics is the accurate and comprehensive annotation of high-resolution tandem mass spectral data. While the number of available lipidomics software has drastically increased over the past five years, the reduction of false positives and the realization of obtaining structurally accurate annotations remains a significant challenge. We introduce Lipid Annotator, which is a user-friendly software for lipidomic analysis of data collected by liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). We validate annotation accuracy against lipid standards and other lipidomics software. Lipid Annotator was integrated into a workflow applying an iterative exclusion MS/MS acquisition strategy to National Institute of Standards and Technology (NIST) SRM 1950 Metabolites in Frozen Human Plasma using reverse phase LC-HRMS/MS. Lipid Annotator, LipidMatch, and MS-DIAL produced consensus annotations at the level of lipid class for 98% and 96% of features detected in positive and negative mode, respectively. Lipid Annotator provides percentages of fatty acyl constituent species and employs scoring algorithms based on probability theory, which is less subjective than the tolerance and weighted match scores commonly used by available software. Lipid Annotator enables analysis of large sample cohorts and improves data-processing throughput as compared to previous lipidomics software.
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Oulkar, Dasharath P., Kaushik Banerjee und Sunil Kulkarni. „Multiresidue Analysis of Plant Growth Regulators in Grapes by Triple Quadrupole and Quadrupole–Time of Flight-Based Liquid Chromatography/Mass Spectrometry“. Journal of AOAC INTERNATIONAL 94, Nr. 6 (01.11.2011): 1715–21. http://dx.doi.org/10.5740/jaoacint.sgeoulkar.

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Abstract A selective and sensitive LC-MS/MS method is presented for simultaneous determination of 12 plant growth regulators, viz., indol-3-acetic acid, indol-3-butyric acid, kinetin, zeatin, 6-benzyl aminopurine, gibberellic acid, abscisic acid, chlormequat chloride, forchlorfenuron, paclobutrazole, daminozide, and 2,4-dichlorophenoxy acetic acid, in bud sprouts and grape berries. The sample preparation method involved extraction of homogenized sample (5 g) with 40 mL methanol (80%), and final determination was by LC-MS/MS in the multiple reaction monitoring (MRM) mode with time segmentation for quantification supported by complementary analysis by quadrupole-time of flight (Q-TOF) MS with targeted high-resolution MS/MS scanning for confirmatory identification based on accurate mass measurements. The recovery of the test compounds ranged within 90–107% with precision RSD less than 5% (n = 6). The method could be successfully applied in analyzing incurred residue samples, and the strength of accurate mass analysis could be utilized in identifying the compounds in cases where the qualifier MRM ions were absent or at an S/N less than 3:1 due to low concentrations.
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Duzan, Ashraf, Desiree Reinken und Mufeed M. Basti. „Quality Control of 11 Cannabinoids by Ultraperformance Liquid Chromatography Coupled with Mass Spectrometry (UPLC-MS/MS)“. Journal of Analytical Methods in Chemistry 2023 (10.08.2023): 1–8. http://dx.doi.org/10.1155/2023/3753083.

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Objective. Cannabinoid extraction from Cannabis sativa L. (hemp) for nonmedical purposes has become popular in the United States. Concerns, however, have been raised regarding the accuracy of the labels for cannabinoid levels in the commercial products. Methods. In this study, we developed rapid, sensitive, selective, accurate, and validated liquid chromatography-tandem mass spectrometry for the quantification of cannabinoids. The methods are for determining 11 cannabinoids in cannabis (hemp) extracted in oil form, and we investigated the accuracy of the labeling and thermal stability regarding the cannabinoids on 17 oil cannabis samples. Results. In the UPLC chromatogram, we see a good resolution and there is no matrix effect and the accuracy were 98.2% to 102.6%, and the precision was 0.52%–8.18%. The linearity of the calibration curves in methanol was with a regression r2 ≥ 0.99. The lowest of detection (LOD) was 5–25 ng/mL, and the limit of quantification (LOQ) was 10–50 ng/mL. The study showed that only 30% of the commercial samples were within the acceptable range of +/−10% compared to the labeled ingredient concentrations. The thermal stability test profile showed a change in the concentration of cannabinoids in each sample at 37°C for one week, with an average loss of cannabinoids up to 15%. Conclusion. The validated method proved to be selective, accurate, and precise, with acceptable linearity within the calibration range with no matrix effect. The stability profile data indicated that high temperatures could change the quality of commercial samples.
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Zhang, Jida, Hao Cai, Gang Cao, Xiao Liu, Chengping Wen und Yongsheng Fan. „Exploring Potential Chemical Transformation by Chemical Profiling Approach for Rapidly Evaluating Chemical Consistency between Sun-Dried and Sulfur-Fumigated Radix Paeoniae Alba Using Ultraperformance Liquid Chromatography Coupled with Time-of-Flight Mass Spectrometry“. Evidence-Based Complementary and Alternative Medicine 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/763213.

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Ultraperformance liquid chromatography coupled with time-of-flight mass spectrometry (UPLC-QTOF/MS) based on a chemical profiling method was applied to rapidly evaluate the chemical consistency between sun-dried and sulfur-fumigated Radix Paeoniae Alba. By virtue of the high resolution, high speed of UPLC, and the accurate mass measurement of TOFMS coupled with reliable MarkerLynx software, five newly assigned monoterpene glycoside sulfonates were found and identified in sulfur-fumigated Radix Paeoniae Alba samples. This method could be applied for rapid quality evaluation of different kinds of sulfur-fumigated Radix Paeoniae Alba among commercial samples.
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Marchei, Emilia, Maria Alias Ferri, Marta Torrens, Magí Farré, Roberta Pacifici, Simona Pichini und Manuela Pellegrini. „Ultra-High Performance Liquid Chromatography-High Resolution Mass Spectrometry and High-Sensitivity Gas Chromatography-Mass Spectrometry Screening of Classic Drugs and New Psychoactive Substances and Metabolites in Urine of Consumers“. International Journal of Molecular Sciences 22, Nr. 8 (13.04.2021): 4000. http://dx.doi.org/10.3390/ijms22084000.

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The use of the new psychoactive substances is continuously growing and the implementation of accurate and sensible analysis in biological matrices of users is relevant and fundamental for clinical and forensic purposes. Two different analytical technologies, high-sensitivity gas chromatography-mass spectrometry (GC-MS) and ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UHPLC-HRMS) were used for a screening analysis of classic drugs and new psychoactive substances and their metabolites in urine of formed heroin addicts under methadone maintenance therapy. Sample preparation involved a liquid-liquid extraction. The UHPLC-HRMS method included Accucore™ phenyl Hexyl (100 × 2.1 mm, 2.6 μm, Thermo, USA) column with a gradient mobile phase consisting of mobile phase A (ammonium formate 2 mM in water, 0.1% formic acid) and mobile phase B (ammonium formate 2 mM in methanol/acetonitrile 50:50 (v/v), 0.1% formic acid) and a full-scan data-dependent MS2 (ddMS2) mode for substances identification (mass range 100–1000 m/z). The GC-MS method employed an ultra-Inert Intuvo GC column (HP-5MS UI, 30 m, 250 µm i.d, film thickness 0.25 µm; Agilent Technologies, Santa Clara, CA, USA) and electron-impact (EI) mass spectra were recorded in total ion monitoring mode (scan range 40–550 m/z). Urine samples from 296 patients with a history of opioid use disorder were examined. Around 80 different psychoactive substances and/or metabolites were identified, being methadone and metabolites the most prevalent ones. The possibility to screen for a huge number of psychotropic substances can be useful in suspected drug related fatalities or acute intoxication/exposure occurring in emergency departments and drug addiction services.
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Zhao, Shumao, Rongkun Jia, Qiuchan Han, Niande Shang, Kaiyan Teng und Jiawei Feng. „Comparison of the Application of High-Resolution Inductively Coupled Plasma Mass Spectrometry (HR-ICP-MS) and Collision/Reaction Cell Technology of Inductively Coupled Plasma Mass Spectrometry (ICP-CCT-MS) in the Determination of Selenium in Coal-Bearing Strata“. Minerals 14, Nr. 5 (13.05.2024): 510. http://dx.doi.org/10.3390/min14050510.

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Selenium, a trace element of significant importance for human health and the environment, can be introduced into the environment through coal combustion. Accurate determination of selenium in coal and coal-bearing strata is essential for implementing effective management strategies and control measures to minimize potential risks to human health and the environment. This study introduces an improved approach for the determination of 77Se in the medium resolution mode using HR-ICP-MS, effectively separating interference from doubly charged ions and enabling precise determination of selenium in coal-bearing strata. The relative errors of the standard reference samples obtained by HR-ICP-MS are between 0.65% and 6.33%, comparing to that of ICP-CCT-MS (1.58%–17.27%), prove the reliability of this method. Additionally, the X (bar)—S control charts obtained from HR-ICP-MS compared to ICP-CCT-MS demonstrate the superior stability of HR-ICP-MS in continuous determination. Consequently, though ICP-CCT-MS has better instrumental stability reflected through the internal standard recovery (ICP-CCT-MS:104.81%; HR-ICP-MS:80.54%), HR-ICP-MS is recommended as the preferred method for selenium determination in coal-bearing strata because of its high accuracy and good stability.
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Leite, Marta, Ana Rita Marques, Ana Sofia Vila Pouca, Silvia Cruz Barros, Jorge Barbosa, Fernando Ramos, Isabel Maria Afonso und Andreia Freitas. „UHPLC-ToF-MS as a High-Resolution Mass Spectrometry Tool for Veterinary Drug Quantification in Milk“. Separations 10, Nr. 8 (21.08.2023): 457. http://dx.doi.org/10.3390/separations10080457.

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Milk is one of the most widely consumed foods in the world, despite the increasing consumption of plant-based alternatives. Although rich in nutrients and believed by consumers to be free of undesirable contaminants, milk, whether of animal or plant origin, is not always free from residues of chemical substances, including veterinary medicines. For instance, in intensive livestock production, antibiotics are often used to treat animals or, illicitly, to improve their growth performance, which can lead to their presence in the final food. Additionally, the continuous use of veterinary drugs in intensive animal production can lead to their occurrence in agricultural soils and therefore are absorbed by plants as another source of entering the food chain. An effective and accurate multi-detection quantitative screening method to analyze 89 antibiotics in milk was optimized by ultra-high-performance liquid chromatography coupled with a time-of-flight detector (UHPLC-ToF-MS) and further validated in accordance with the Commission Implementing Regulation (CIR) 808/2021 and the International Council for Harmonization (ICH) guidelines on the validation of analytical procedures. Apart from the specific parameters required by CIR 808/2021, the aim was to access the lower limits of the method, limits of detection (LoD) and quantification (LoQ), regardless of the maximum residue limits (MRLs) defined in the legislation. The method was then applied in the analysis of 32 supermarket samples, resulting in four positive findings, including one plant-based sample. The antibiotics found were from the macrolides and sulphonamides families. Nevertheless, the concentrations detected were below the established maximum residue level (MRL).
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Tanna, Sangeeta, Ahmed Alalaqi, Dennis Bernieh und Graham Lawson. „Volumetric absorptive microsampling (VAMS) coupled with high-resolution, accurate-mass (HRAM) mass spectrometry as a simplified alternative to dried blood spot (DBS) analysis for therapeutic drug monitoring of cardiovascular drugs“. Clinical Mass Spectrometry 10 (Dezember 2018): 1–8. http://dx.doi.org/10.1016/j.clinms.2018.08.002.

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47

Sun, Feifei, Haiguang Tan, Yanshen Li, Marthe De Boevre, Sarah De Saeger, Jinhui Zhou, Yi Li, Zhenghua Rao, Shupeng Yang und Huiyan Zhang. „Metabolic Profile, Bioavailability and Toxicokinetics of Zearalenone-14-Glucoside in Rats after Oral and Intravenous Administration by Liquid Chromatography High-Resolution Mass Spectrometry and Tandem Mass Spectrometry“. International Journal of Molecular Sciences 20, Nr. 21 (03.11.2019): 5473. http://dx.doi.org/10.3390/ijms20215473.

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Zearalenone-14-glucoside (ZEN-14G), a key modified mycotoxin, has attracted a great deal of attention due to the possible conversion to its free form of zearalenone (ZEN) exerting toxicity. In this study, the toxicokinetics of ZEN-14G were investigated in rats after oral and intravenous administration. The plasma concentrations of ZEN-14G and its major five metabolites were quantified using a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. The data were analyzed via non-compartmental analysis using software WinNonlin 6.3. The results indicated that ZEN-14G was rapidly hydrolyzed into ZEN in vivo. In addition, the major parameters of ZEN-14G following intravenous administration were: area under the plasma concentration–time curve (AUC), 1.80 h·ng/mL; the apparent volume of distribution (VZ), 7.25 L/kg; and total body clearance (CL), 5.02 mL/h/kg, respectively. After oral administration, the typical parameters were: AUC, 0.16 h·ng/mL; VZ, 6.24 mL/kg; and CL, 4.50 mL/h/kg, respectively. The absolute oral bioavailability of ZEN-14G in rats was about 9%, since low levels of ZEN-14G were detected in plasma, which might be attributed to its extensive metabolism. Therefore, liquid chromatography high-resolution mass spectrometry (LC-HRMS) was adopted to clarify the metabolic profile of ZEN-14G in rats’ plasma. As a result, eight metabolites were identified in which ZEN-14-glucuronic acid (ZEN-14GlcA) had a large yield from the first time-point and continued accumulating after oral administration, indicating that ZEN-14-glucuronic acid could serve a potential biomarker of ZEN-14G. The obtained outcomes would prompt the accurate safety evaluation of ZEN-14G.
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Nagaraju, Pappula, Balaji Kodali, Peda Varma Datla und Surya Prakasarao Kovvasu. „LC-MS/MS Quantification of Tramadol and Gabapentin Utilizing Solid Phase Extraction“. International Journal of Analytical Chemistry 2018 (28.10.2018): 1–9. http://dx.doi.org/10.1155/2018/1605950.

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An accurate, highly sensitive, and precise method for quantitative analysis of tramadol (TMD) and gabapentin (GBP) by high performance liquid chromatography and tandem mass spectrometry in human plasma was proposed and validated successfully using venlafaxine and pregabalin as internal standards (ISTDs), respectively. An aliquot of 200 μL of plasma was mixed with internal standard dilution and extraction was performed by using solid phase extraction (SPE) technique. Peak resolution was achieved on Phenomenex PFP column (50×4.6 mm, 2.6 μm). The total analytical run time was 3.8 min. Both analytes were monitored using multiple reaction monitoring (MRM) scan and the mass spectrometer was operated in positive polarity mode. The method was validated for specificity, sensitivity, precision, accuracy, and other analytical parameters. The results found were satisfactory over the linear calibration range of 1-500 ng/mL and 10-6000 ng/mL for TMD and GBP, respectively. The developed method can be ready to use by scientific community for quantification of analytes in plasma samples from various clinical studies of different dose strengths.
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Badescu, Virgil. „TEOS Oligomers and Transesters Identified by GC-MS in the sol-gel Process. Operational Mass Spectral Libraries“. Revista de Chimie 73, Nr. 3 (29.07.2022): 1–13. http://dx.doi.org/10.37358/rc.22.3.8530.

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The aim of this article is the presentation of new user mass spectral libraries created based on unambiguous assigning of the mass spectra of the tetraethoxysilane (TEOS) oligomers and transesters obtained in the sol-gel process. Gas-chromatography coupled with mass spectrometry (GC-MS) was used to unambiguous identification the TEOS oligomers and transesters obtained in the hydrolysis, condensation and transesterification, reactions of tetraethoxysilane in parental solvent (EtOH) and nonparental solvents (MeOH and n-PrOH). The author�s procedure for the interpretation of mass spectra of silicon alkoxides was applied for TEOS, TEOS dimer, methoxy-transesters, and TEOS cyclic tetramer. GC and MS arguments for unambiguous assigning of TEOS oligomers and transesters in the sol-gel process were presented. Experimental B/E and B/E(1-E)1/2 linked scans, accurate mass at high resolution and M+1, M+2 isotopic effects, applied in previous works, were used as MS arguments. The NBS mass spectral library run under the RSX-11-PLUS operating system was used to create new mass spectral libraries. In this article are presented three user mass spectral libraries codified: TRANSME0 for methoxy-transesters, PROPOXY1 for propoxy-transesters in the histogram plot and tabular format and ICECHIM6 (first 12 entries in histogram plot format) for TEOS oligomers in the parental solvent.
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Kiselar, Janna, und Mark R. Chance. „High-Resolution Hydroxyl Radical Protein Footprinting: Biophysics Tool for Drug Discovery“. Annual Review of Biophysics 47, Nr. 1 (20.05.2018): 315–33. http://dx.doi.org/10.1146/annurev-biophys-070317-033123.

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Hydroxyl radical footprinting (HRF) of proteins with mass spectrometry (MS) is a widespread approach for assessing protein structure. Hydroxyl radicals react with a wide variety of protein side chains, and the ease with which radicals can be generated (by radiolysis or photolysis) has made the approach popular with many laboratories. As some side chains are less reactive and thus cannot be probed, additional specific and nonspecific labeling reagents have been introduced to extend the approach. At the same time, advances in liquid chromatography and MS approaches permit an examination of the labeling of individual residues, transforming the approach to high resolution. Lastly, advances in understanding of the chemistry of the approach have led to the determination of absolute protein topologies from HRF data. Overall, the technology can provide precise and accurate measures of side-chain solvent accessibility in a wide range of interesting and useful contexts for the study of protein structure and dynamics in both academia and industry.

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