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Journal articles on the topic 'MALDI matrix'

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Published: 22 December 2023

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1

TANAKA, Koichi. "Preface: Issuing “MALDI Matrix”." Journal of the Mass Spectrometry Society of Japan 64, no. 5 (2016): 167. http://dx.doi.org/10.5702/massspec.s16-34.

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2

Fukuyama, Yuko. "MALDI Matrix Research for Biopolymers." Mass Spectrometry 4, no. 1 (2015): A0037. http://dx.doi.org/10.5702/massspectrometry.a0037.

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3

Martic, Sanela, John D. Brennan, Michael A. Brook, Suzanne Ackloo, and Noemi Nagy. "Towards the development of a covalently tethered MALDI system — A study of allyl-modified MALDI matrixes." Canadian Journal of Chemistry 85, no. 1 (January 1, 2007): 66–76. http://dx.doi.org/10.1139/v06-185.

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An emerging application of matrix-assisted laser desorption ionization (MALDI) mass spectrometry is the analysis of low molecular weight (LMW) compounds, often via coupled liquid chromatography — MALDI-MS methods. However, in many cases, the low molecular weight region of MALDI mass spectra is obscured by the presence of signals originating from the matrix, suggesting that the development of tethered MALDI matrixes may be required to optimize MS performance for such compounds. To gain insight into potential sites for covalent attachment of MALDI matrixes, we have systematically investigated the role played by a variety of functional group motifs in determining matrix efficiency for three common MALDI matrixes, as judged both by total signal intensity and background noise from matrix decomposition for a set of LMW compounds. A series of allyl derivatives of standard matrixes was prepared, and the efficiency of these materials in the MALDI experiment was measured. All modifications of established matrixes, e.g., 2,5-dihydroxybenzoic acid (DHB), α-cyano-4-hydroxycinnamic acid (CHCA), and caffeic acid (CA), or close analogues led to decreased absolute signal intensity and signal-to-background levels. Improved performance was generally observed with (i) the presence of a phenolic group (carboxylic acids were less effective) (ii) crystalline derivatives, and (iii) compounds that had high extinction coefficients at wavelengths near to that of the exciting laser (337 nm). The most interesting derivatives were the O-allyl ether (15) and N-allyl amide (16) of caffeic acid. These compounds did not facilitate signals from all four analytes tested. However, the observed spectra contained fewer signals from the matrix than from the parent compound CA. These compounds demonstrate that functionalization of MALDI matrixes, ultimately leading to tethered matrixes, is possible without jeopardizing signal intensity.Key words: MALDI, protected matrix, phenol, caffeic acid, allyl ether.
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4

Gorbunov A. Yu. and Podolskaya E. P. "Fabrication of nanoscale multimolecular structures of lanthanum stearate using Langmuir monolayers for laser desorption/ionization mass spectrometry." Technical Physics Letters 48, no. 11 (2022): 29. http://dx.doi.org/10.21883/tpl.2022.11.54885.19320.

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Matrix-assisted laser desorption/ionization (MALDI) from the surface of nanosized multimolecular structures based on lanthanum stearate monolayers (FLa) has been studied. The presence of FLa on the surface of MALDI target was confirmed experimentally by laser desorption of lanthanum-containing organic ions. MALDI target functionalization with FLa is shown to significantly increase the yield of target peptide ions, with the optimum being achieved at a film thickness of about 6 monolayers. An approach is proposed in a "lab-on-a-plate" format, which allows specific extraction of peptides modified with chlorine-containing compounds and includes the following steps: functionalization of the target surface, metal affinity extraction, matrix deposition and MALDI mass spectrometric analysis. Keywords: mass spectrometry, matrix assisted laser desorption/ionization (MALDI), surface, Langmuir monolayers, metal affinity chromatography.
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Montaudo, Giorgio, Filippo Samperi, Maurizio S. Montaudo, Sabrina Carroccio, and Concetto Puglisi. "Current Trends in Matrix-Assisted Laser Desorption/Ionization of Polymeric Materials." European Journal of Mass Spectrometry 11, no. 1 (February 2005): 1–14. http://dx.doi.org/10.1255/ejms.718.

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In the last few years, mass spectrometry has rapidly become indispensable in polymer analysis and complements, in many ways, the structural data provided by nuclear magnetic resonance. Mass spectrometry of polymers is emerging as a revolutionary technique, capable of challenging the techniques and protocols established for years for the characterization of synthetic polymers. Matrix-assisted laser desorption/ionization (MALDI) has become a widely applied method for the structural characterization of synthetic polymers. The primary aim of this review is to illustrate some recent advances in the study of macromolecular systems by MALDI. MALDI allows the identification of repeat units and end groups, the structural analysis of linear and cyclic oligomers and the estimate of composition and sequence for co-polymers. MALDI is also quite useful for the measurement of molar mass and bivariate distributions in polymers and for the detection of self-association in macromolecules, performed by coupling MALDI with size exclusion chromatography (SEC). Recently MALDI has been applied, with remarkable success, to the study of thermal and oxidative processes in polymers and to the characterization of co-polymers obtained by reactive polymer blending. Selected applications of MALDI to polymers are illustrated herewith.
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6

Lippa, Timothy, Nelli I. Taranenko, Coorg R. Prasad, and Vladimir M. Doroshenko. "Infrared Matrix-Assisted Laser Desorption/Ionization Quadrupole Ion Trap Mass Spectrometry." European Journal of Mass Spectrometry 8, no. 3 (June 2002): 263–71. http://dx.doi.org/10.1255/ejms.498.

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Performance characteristics of an infrared (IR) matrix-assisted laser desorption/ionization (MALDI) quadrupole ion trap (QIT) mass spectrometer are presented. Both an IR laser and an ultraviolet (UV) laser have been coupled to the MALDI ion source, allowing for a comparative study of the spectra obtained for the same analyte molecules taken at these two wavelengths. The mass range of the QIT instrument was extended by operating it at a frequency as low as 200 kHz. The results presented for small and medium-size peptides demonstrated a lesser degree of analyte ion fragmentation in the case of the IR-MALDI source compared with that obtained using the UV-MALDI source. Due to the fragmentation phenomenon, the mass resolution for cytochrome C ions(MW12384 Da) was an order of a magnitude higher in the case of IR-MALDI compared with the use of UV-MALDI. This phenomenon has been shown to effect the calibration of the trap instrument for higher masses.
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7

Fresnais, Margaux, Esra Yildirim, Seda Karabulut, Dirk Jäger, Inka Zörnig, Julia Benzel, Kristian W. Pajtler, et al. "Rapid MALDI-MS Assays for Drug Quantification in Biological Matrices: Lessons Learned, New Developments, and Future Perspectives." Molecules 26, no. 5 (February 26, 2021): 1281. http://dx.doi.org/10.3390/molecules26051281.

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Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) has rarely been used in the field of therapeutic drug monitoring, partly because of the complexity of the ionization processes between the compounds to be quantified and the many MALDI matrices available. The development of a viable MALDI-MS method that meets regulatory guidelines for bioanalytical method validation requires prior knowledge of the suitability of (i) the MALDI matrix with the analyte class and properties for ionization, (ii) the crystallization properties of the MALDI matrix with automation features, and (iii) the MS instrumentation used to achieve sensitive and specific measurements in order to determine low pharmacological drug concentrations in biological matrices. In the present hybrid article/white paper, we review the developments required for the establishment of MALDI-MS assays for the quantification of drugs in tissues and plasma, illustrated with concrete results for the different steps. We summarize the necessary parameters that need to be controlled for the successful development of fully validated MALDI-MS methods according to regulatory authorities, as well as currently unsolved problems and promising ways to address them. Finally, we propose an expert opinion on future perspectives and needs in order to establish MALDI-MS as a universal method for therapeutic drug monitoring.
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8

Israr, Muhammad Zubair, Dennis Bernieh, Andrea Salzano, Shabana Cassambai, Yoshiyuki Yazaki, and Toru Suzuki. "Matrix-assisted laser desorption ionisation (MALDI) mass spectrometry (MS): basics and clinical applications." Clinical Chemistry and Laboratory Medicine (CCLM) 58, no. 6 (June 25, 2020): 883–96. http://dx.doi.org/10.1515/cclm-2019-0868.

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AbstractBackgroundMatrix-assisted laser desorption ionisation (MALDI) mass spectrometry (MS) has been used for more than 30 years. Compared with other analytical techniques, it offers ease of use, high throughput, robustness, cost-effectiveness, rapid analysis and sensitivity. As advantages, current clinical techniques (e.g. immunoassays) are unable to directly measure the biomarker; rather, they measure secondary signals. MALDI-MS has been extensively researched for clinical applications, and it is set for a breakthrough as a routine tool for clinical diagnostics.ContentThis review reports on the principles of MALDI-MS and discusses current clinical applications and the future clinical prospects for MALDI-MS. Furthermore, the review assesses the limitations currently experienced in clinical assays, the advantages and the impact of MALDI-MS to transform clinical laboratories.SummaryMALDI-MS is widely used in clinical microbiology for the screening of microbial isolates; however, there is scope to apply MALDI-MS in the diagnosis, prognosis, therapeutic drug monitoring and biopsy imaging in many diseases.OutlookThere is considerable potential for MALDI-MS in clinic as a tool for screening, profiling and imaging because of its high sensitivity and specificity over alternative techniques.
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9

Creaser, Colin S., James C. Reynolds, Andrew J. Hoteling, William F. Nichols, and Kevin G. Owens. "Atmospheric Pressure Matrix-Assisted Laser Desorption/Ionisation Ion Trap Mass Spectrometry of Synthetic Polymers: A Comparison with Vacuum Matrix-Assisted Laser Desorption/Ionisation Time-of-Flight Mass Spectrometry." European Journal of Mass Spectrometry 9, no. 1 (February 2003): 33–44. http://dx.doi.org/10.1255/ejms.528.

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Atmospheric pressure matrix-assisted laser desorption/ionisation quadrupole ion trap (AP-MALDI/QIT) mass spectrometry has been investigated for the analysis of polyethylene glycol (PEG 1500) and a hyperbranched polymer (polyglycidol) in the presence of alkali–metal salts. Mass spectra of PEG 1500 obtained at atmospheric pressure showed dimetallated matrix/analyte adducts, in addition to the expected alkali–metal/PEG ions, for all matrix/alkali–metal salt combinations. The relative intensities of the desorbed ions were dependent on the matrix, the alkali–metal salt added to aid cationisation and the ion trap interface conditions [capillary temperature, in-source collisionally-induced dissociation (CID)]. These data indicate that the adducts are rapidly stabilised by collisional cooling enabling them to be transferred into the ion trap. Experiments using identical sample preparation conditions were carried out on a vacuum MALDI time-of-flight (ToF) mass spectrometer. In all cases, vacuum MALDI-ToF spectra showed only alkali–metal/PEG ions and no matrix/analyte adducts. The tandem mass spectrometry (MS/MS) capability of the ion trap has been demonstrated for a lithiated polyglycol yielding a rich fragment-ion spectrum. Analysis of the hyperbranched polymer polyglycidol by AP-MALDI/QIT reveals the characteristic ion series for these polymers as also observed under vacuum MALDI-ToF conditions.
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10

Flensburg, John, Anders Tangen, Maria Prieto, Ulf Hellman, and Henrik Wadensten. "Chemically-Assisted Fragmentation Combined with Multi-Dimensional Liquid Chromatography and Matrix-Assisted Laser Desorption/Ionization Post Source Decay, Matrix-Assisted Laser Desorption/Ionization Tandem Time-of-Flight or Matrix-Assisted Laser Desorption/Ionization Tandem Mass Spectrometry for Improved Sequencing of Tryptic Peptides." European Journal of Mass Spectrometry 11, no. 2 (April 2005): 169–79. http://dx.doi.org/10.1255/ejms.734.

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Derivatization of tryptic peptides using an Ettan CAF matrix-assisted laser desorption/ionization (MALDI) sequencing kit in combination with MALDI-post source decay (PSD) is a fast, accurate and convenient way to obtain de novo or confirmative peptide sequencing data. CAF (chemically assisted fragmentation) is based on solid-phase derivatization using a new class of water stable sulfonation agents, which strongly improves PSD analysis and simplifies the interpretation of acquired spectra. The derivatization is performed on solid supports, ZipTipμC18, limiting the maximum peptide amount to 5 μg. By performing the derivatization in solution enabled the labeling of tryptic peptides derived from 100 μg of protein. To increase the number of peptides that could be sequenced, derivatized peptides were purified using multidimensional liquid chromatography (MDLC) prior to MALDI sequencing. Following the first dimension strong cation exchange (SCX) chromatography step, modified peptides were separated using reversed-phase chromatography (RPC). During the SCX clean up step, positively charged peptides are retained on the column while properly CAF-derivatized peptides (uncharged) are not. A moderately complex tryptic digest, prepared from six different proteins of equimolar amounts, was CAF-derivatized and purified by MDLC. Fractions from the second dimension nano RPC step were automatically sampled and on-line dispensed to MALDI sample plates and analyzed using MALDI mass spectrometry fragmentation techniques. All proteins in the derivatized protein mixture digest were readily identified using MALDI-PSD or MALDI tandem mass spectrometry (MS/MS). More than 40 peptides were unambiguously sequenced, representing a seven-fold increase in the number of sequenced peptides in comparison to when the CAF-derivatized protein mix digest was analyzed directly (no MDLC-separation) using MALDI-PSD. In conclusion, MDLC purification of CAF-derivatized peptides significantly increases the success rate for de novo and confirmative sequencing using various MALDI fragmentation techniques. This new approach is not only applicable to single protein digests but also to more complex digests and could, thus, be an alternative to electrospray ionization MS/MS for peptide sequencing.
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11

Osa, Morichika, Maria Cecilia Belo, Zita Dela Merced, Annavi Marie G. Villanueva, Jaira Mauhay, Alyannah Celis, Melissa Catli, et al. "Performance of MALDI–TOF Mass Spectrometry in the Philippines." Tropical Medicine and Infectious Disease 6, no. 3 (June 26, 2021): 112. http://dx.doi.org/10.3390/tropicalmed6030112.

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Identification of the causative pathogen in infectious diseases is important for surveillance and to guide treatment. In low- and middle-income countries (LMIC), conventional culture and identification methods, including biochemical methods, are reference-standard. Biochemical methods can lack sensitivity and specificity and have slow turnaround times, causing delays in definitive therapy. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI–TOF MS) is a rapid and accurate diagnostic method. Most studies comparing MALDI–TOF MS and biochemical methods are from high-income countries, with few reports from LMIC with tropical climates. The aim of this study was to assess the performance of MALDI–TOF MS compared to conventional methods in the Philippines. Clinical bacterial or fungal isolates were identified by both MALDI–TOF MS and automated (VITEK2) or manual biochemical methods in the San Lazaro Hospital, Metro Manila, the Philippines. The concordance between MALDI­–TOF MS and automated (VITEK2) or manual biochemical methods was analyzed at the species and genus levels. In total, 3530 bacterial or fungal isolates were analyzed. The concordance rate between MALDI–TOF MS and biochemical methods was 96.2% at the species level and 99.9% at the genus level. Twenty-three isolates could not be identified by MALDI–TOF MS. In this setting, MALDI–TOF MS was accurate compared with biochemical methods, at both the genus and the species level. Additionally, MALDI–TOF MS improved the turnaround time for results. These advantages could lead to improved infection management and infection control in low- and middle-income countries, even though the initial cost is high.
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12

Barada, Erina, and Hiroshi Hinou. "BOA/DHB/Na: An Efficient UV-MALDI Matrix for High-Sensitivity and Auto-Tagging Glycomics." International Journal of Molecular Sciences 23, no. 20 (October 19, 2022): 12510. http://dx.doi.org/10.3390/ijms232012510.

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Matrix selection is a critical factor for success in glycomics studies using matrix-assisted laser desorption/ionization–mass spectrometry (MALDI–MS). In this study, we evaluated and optimized a new solid ionic matrix—O-benzylhydroxylamine (BOA)/2,5-dihydroxybenzoic acid (DHB)/Na—containing BOA and a small amount of sodium as the counter salt of DHB. The concentration of a mixture of BOA/DHB/Na and glycans on a MALDI target plate led to O-benzyloxy tagging of the reducing ends of the glycans. The BOA/DHB/Na matrix showed excellent aggregation performance and the ability to form a homogeneous solid salt on the MALDI target plate with a water-repellent surface. In addition, the BOA/DHB/Na matrix showed a simple peak pattern with suppressed in-source and post-source decay of the reducing ends of the glycans, as well as improved ionization efficiency of glycans. Utilizing the characteristics of the BOA/DHB/Na matrix, O-glycan analysis of porcine stomach mucin showed excellent detection sensitivity and reproducibility of the peak patterns. This BOA/DHB/Na matrix can accelerate glycomics studies using MALDI–MS and, in combination with other organic salt-type matrices that we have developed, constitutes a valuable tool for glycomics studies.
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13

Giampà, M., M. B. Lissel, T. Patschkowski, J. Fuchser, V. H. Hans, O. Gembruch, H. Bednarz, and K. Niehaus. "Maleic anhydride proton sponge as a novel MALDI matrix for the visualization of small molecules (<250 m/z) in brain tumors by routine MALDI ToF imaging mass spectrometry." Chemical Communications 52, no. 63 (2016): 9801–4. http://dx.doi.org/10.1039/c6cc02387h.

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14

Hou, Junjie, Zhensheng Xie, Peng Xue, Ziyou Cui, Xiulan Chen, Jing Li, Tanxi Cai, Peng Wu, and Fuquan Yang. "Enhanced MALDI-TOF MS Analysis of Phosphopeptides Using an Optimized DHAP/DAHC Matrix." Journal of Biomedicine and Biotechnology 2010 (2010): 1–12. http://dx.doi.org/10.1155/2010/759690.

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Selecting an appropriate matrix solution is one of the most effective means of increasing the ionization efficiency of phosphopeptides in matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In this study, we systematically assessed matrix combinations of 2, 6-dihydroxyacetophenone (DHAP) and diammonium hydrogen citrate (DAHC), and demonstrated that the low ratio DHAP/DAHC matrix was more effective in enhancing the ionization of phosphopeptides. Low femtomole level of phosphopeptides from the tryptic digests ofα-casein andβ-casein was readily detected by MALDI-TOF-MS in both positive and negative ion mode without desalination or phosphopeptide enrichment. Compared with the DHB/PA matrix, the optimized DHAP/DAHC matrix yielded superior sample homogeneity and higher phosphopeptide measurement sensitivity, particularly when multiple phosphorylated peptides were assessed. Finally, the DHAP/DAHC matrix was applied to identify phosphorylation sites fromα-casein andβ-casein and to characterize two phosphorylation sites from the human histone H1 treated with Cyclin-Dependent Kinase-1 (CDK1) by MALDI-TOF/TOF MS.
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15

Lippa, T. P., S. N. Eustis, D. Wang, and K. H. Bowen. "Electrophilic properties of common MALDI matrix molecules." International Journal of Mass Spectrometry 268, no. 1 (November 2007): 1–7. http://dx.doi.org/10.1016/j.ijms.2007.07.019.

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16

Zhang, Juan, and Renato Zenobi. "Matrix-dependent cationization in MALDI mass spectrometry." Journal of Mass Spectrometry 39, no. 7 (July 2004): 808–16. http://dx.doi.org/10.1002/jms.657.

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17

Robinson, Kenneth N., Rory T. Steven, and Josephine Bunch. "Matrix Optical Absorption in UV-MALDI MS." Journal of The American Society for Mass Spectrometry 29, no. 3 (November 29, 2017): 501–11. http://dx.doi.org/10.1007/s13361-017-1843-4.

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18

Oluwatosin Ogundairo, Oluwatoyin Ayo-Farai, Chinedu Paschal Maduka, Chiamaka Chinaemelum Okongwu, Abdulraheem Olaide Babarinde, and Olamide Tolulope Sodamade. "REVIEW ON MALDI MASS SPECTROMETRY AND ITS APPLICATION IN CLINICAL RESEARCH." International Medical Science Research Journal 3, no. 3 (December 12, 2023): 108–26. http://dx.doi.org/10.51594/imsrj.v3i3.642.

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Mass spectrometry has emerged as a powerful analytical tool in various scientific disciplines, and Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) has gained significant prominence, particularly in the field of clinical research. This review provides a comprehensive overview of MALDI-MS, its principles, and its applications in clinical research settings. This study delves into the technical aspects of MALDI-MS, discussing key components such as the matrix, sample preparation methods, and mass analyzers. It highlights recent advancements and innovations in MALDI-MS technology, showcasing its evolution and adaptation to meet the increasing demands of clinical applications. MALDI-MS involves the use of laser energy to desorb and ionize molecules from a solid-phase matrix, enabling the analysis of a wide range of biomolecules, including proteins, peptides, lipids, and metabolites. The technique's ability to analyze complex biological samples with high sensitivity and specificity has made it invaluable in clinical research. In the realm of clinical research, MALDI-MS has found applications in disease diagnosis, biomarker discovery, and therapeutic monitoring. The review explores specific examples of MALDI-MS applications in various clinical areas, including oncology, infectious diseases, and metabolic disorders. Case studies and experimental findings are presented to underscore the practical utility of MALDI-MS in these contexts. Moreover, the review discusses the challenges and limitations associated with MALDI-MS in clinical research, such as standardization of protocols, reproducibility, and sample heterogeneity. Strategies to overcome these challenges are addressed, emphasizing ongoing efforts to enhance the reliability and robustness of MALDI-MS-based analyses in clinical settings. MALDI-MS has proven to be a transformative technology in clinical research, offering unique insights into the molecular landscape of diseases and paving the way for personalized medicine. As MALDI-MS continues to evolve, its integration into routine clinical workflows holds the potential to revolutionize diagnostics and improve patient outcomes. This review serves as a valuable resource for researchers, clinicians, and industry professionals seeking a comprehensive understanding of MALDI-MS and its myriad applications in the field of clinical research. Keywords: MALDI-MS, Clinical Research, Review, Ionization Mass Spectrometry.
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Kim, Seung-Woo, Sunbum Kwon, and Young-Kwan Kim. "Graphene Oxide Derivatives and Their Nanohybrid Structures for Laser Desorption/Ionization Time-of-Flight Mass Spectrometry Analysis of Small Molecules." Nanomaterials 11, no. 2 (January 22, 2021): 288. http://dx.doi.org/10.3390/nano11020288.

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Matrix-assisted laser desorption/ionization (MALDI) has been considered as one of the most powerful analytical tools for mass spectrometry (MS) analysis of large molecular weight compounds such as proteins, nucleic acids, and synthetic polymers thanks to its high sensitivity, high resolution, and compatibility with high-throughput analysis. Despite these advantages, MALDI cannot be applied to MS analysis of small molecular weight compounds (<500 Da) because of the matrix interference in low mass region. Therefore, numerous efforts have been devoted to solving this issue by using metal, semiconductor, and carbon nanomaterials for MALDI time-of-flight MS (MALDI-TOF-MS) analysis instead of organic matrices. Among those nanomaterials, graphene oxide (GO) is of particular interest considering its unique and highly tunable chemical structures composed of the segregated sp2 carbon domains surrounded by sp3 carbon matrix. Chemical modification of GO can precisely tune its physicochemical properties, and it can be readily incorporated with other functional nanomaterials. In this review, the advances of GO derivatives and their nanohybrid structures as alternatives to organic matrices are summarized to demonstrate their potential and practical aspect for MALDI-TOF-MS analysis of small molecules.
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20

Kepper, Pamela, Richard Reinhardt, Andreas Dahl, Hans Lehrach, and Sascha Sauer. "Matrix-Assisted Laser Desorption/Ionization Mass Spectrometric Analysis of DNA on Microarrays." Clinical Chemistry 52, no. 7 (July 1, 2006): 1303–10. http://dx.doi.org/10.1373/clinchem.2006.067264.

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Abstract Background: Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is a powerful tool in biomolecule analysis with a wide range of application possibilities, including genotyping of single-base variations (also known as single-nucleotide polymorphisms, or SNPs) for candidate gene studies and diagnostic typing of DNA markers. We tested a method that does not require stringent purification of the nucleic acids and/or the use of modification chemistry before mass spectrometry analysis. Methods: We used an alternative direct analysis approach that allows MALDI analysis of crude DNA samples printed on microscope slides densely coated with primary amino groups that efficiently bind negatively charged DNA. After simple washing of the slides, we applied MALDI matrix and used a conventional MALDI mass spectrometer to detect DNA products. Results: We analyzed crude oligonucleotide samples and performed automated genotyping of single-base variations in 72 DNA samples. Conclusion: This procedure offers an operational short-cut compared with standard MALDI procedures for preparation of oligonucleotides, including purification, and thus is an efficient tool for genotyping applications, particularly those requiring accurate, flexible, and rapid data generation and medium throughput.
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Müller, Max A., Dhaka R. Bhandari, and Bernhard Spengler. "Matrix-Free High-Resolution Atmospheric-Pressure SALDI Mass Spectrometry Imaging of Biological Samples Using Nanostructured DIUTHAME Membranes." Metabolites 11, no. 9 (September 15, 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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Lellman, Sophie E., and Rainer Cramer. "Bacterial identification by lipid profiling using liquid atmospheric pressure matrix-assisted laser desorption/ionization mass spectrometry." Clinical Chemistry and Laboratory Medicine (CCLM) 58, no. 6 (June 25, 2020): 930–38. http://dx.doi.org/10.1515/cclm-2019-0908.

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AbstractBackgroundIn recent years, mass spectrometry (MS) has been applied to clinical microbial biotyping, exploiting the speed of matrix-assisted laser desorption/ionization (MALDI) in recording microbe-specific MS profiles. More recently, liquid atmospheric pressure (AP) MALDI has been shown to produce extremely stable ion flux from homogenous samples and ‘electrospray ionization (ESI)-like’ multiply charged ions for larger biomolecules, whilst maintaining the benefits of traditional MALDI including high tolerance to contaminants, low analyte consumption and rapid analysis. These and other advantages of liquid AP-MALDI MS have been explored in this study to investigate its potential in microbial biotyping.MethodsGenetically diverse bacterial strains were analyzed using liquid AP-MALDI MS, including clinically relevant species such as Escherichia coli, Staphylococcus aureus and Klebsiella pneumoniae. Bacterial cultures were subjected to a simple and fast extraction protocol using ethanol and formic acid. Extracts were spotted with a liquid support matrix (LSM) and analyzed using a Synapt G2-Si mass spectrometer with an in-house built AP-MALDI source.ResultsEach species produces a unique lipid profile in the m/z range of 400–1100, allowing species discrimination. Traditional (solid) MALDI MS produced spectra containing a high abundance of matrix-related clusters and an absence of lipid peaks. The MS profiles of the bacterial species tested form distinct clusters using principle component analysis (PCA) with a classification accuracy of 98.63% using a PCA-based prediction model.ConclusionsLiquid AP-MALDI MS profiles can be sufficient to distinguish clinically relevant bacterial pathogens and other bacteria, based on their unique lipid profiles. The analysis of the lipid MS profiles is typically excluded from commercial instruments approved for clinical diagnostics.
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Mareković, Ivana, Zrinka Bošnjak, Marko Jakopović, Zagorka Boras, Mateja Janković, and Sanja Popović-Grle. "Evaluation of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry in Identification of Nontuberculous Mycobacteria." Chemotherapy 61, no. 4 (2016): 167–70. http://dx.doi.org/10.1159/000442517.

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Background/Aims: Species-level identification of nontuberculous mycobacteria (NTM) is important in making decisions about the necessity and choice of antimicrobial treatment. The reason is predictable clinical significance and the susceptibility profile of specific NTM species. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is recognized as a diagnostic tool for routine identification of bacteria and yeasts in the clinical laboratory based on protein fingerprint analysis. The aim of the study was to evaluate MALDI-TOF MS in the identification of NTM. Methods: A total of 25 NTM isolates from liquid cultures were identified with both polymerase chain reaction (PCR)-based hybridization assay and MALDI-TOF MS at the University Hospital Center Zagreb. Results: PCR-based hybridization assay identified 96% (24/25) and MALDI-TOF MS 80% (20/25) of tested NTM isolates. Five isolates with no reliable MALDI-TOF MS identification belonged to the Mycobacterium avium-intracellulare complex. Seventy percent (14/20) of NTM isolates successfully identified with MALDI-TOF MS had a score higher than 2.0, indicating reliable species identification. Conclusion: MALDI-TOF MS is a promising tool for the identification of NTM. With a further improvement of the protein extraction protocol, especially regarding the M. avium-intracellulare complex, MALDI-TOF MS could be an additional standard method for identification of NTM.
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Maziarz, E. Peter, and X. Michael Liu. "A Modified Thermal Deposition Unit for Gel-Permeation Chromatography with Matrix-Assisted Laser Desorption/Ionization and Electrospray Ionization Time-of-Flight Analysis." European Journal of Mass Spectrometry 8, no. 5 (October 2002): 397–401. http://dx.doi.org/10.1255/ejms.500.

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We describe a modified commercially available thermal deposition unit that incorporates a post-column mixing cell for gel-permeation chromatography (GPC) effluent and matrix solution prior to continuous deposition onto a matrix-assisted laser desorption/ionization (MALDI) sample target. This modification overcomes the shortcomings of using a prefabricated matrix foil. This GPC MALDI method with time-of-flight (ToF) mass spectrometry is demonstrated by the analysis of a poly(dimethylsiloxane) (PDMS) sample used in the production of implantable device materials.
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Rodríguez-Sánchez, Belén, María Jesús Ruiz-Serrano, Mercedes Marín, Paula López Roa, Marta Rodríguez-Créixems, and Emilio Bouza. "Evaluation of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Identification of Nontuberculous Mycobacteria from Clinical Isolates." Journal of Clinical Microbiology 53, no. 8 (June 10, 2015): 2737–40. http://dx.doi.org/10.1128/jcm.01380-15.

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Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for the identification of nontuberculous mycobacterial (NTM) isolates was evaluated in this study. Overall, 125 NTM isolates were analyzed by MALDI-TOF and GenoType CM/AS. Identification by 16S rRNA/hsp65sequencing was considered the gold standard. Agreements between MALDI-TOF and GenoType CM/AS with the reference method were, respectively, 94.4% and 84.0%. In 17 cases (13.6%), results provided by GenoType and MALDI-TOF were discordant; however, the reference method agreed with MALDI-TOF in 16/17 cases (94.1%;P= 0.002).
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Kucheriavaia, Daria, Dušan Veličković, Nicholas Peraino, Apurva Lad, David J. Kennedy, Steven T. Haller, Judy A. Westrick, and Dragan Isailovic. "Toward Revealing Microcystin Distribution in Mouse Liver Tissue Using MALDI-MS Imaging." Toxins 13, no. 10 (October 8, 2021): 709. http://dx.doi.org/10.3390/toxins13100709.

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Cyanotoxins can be found in water and air during cyanobacterial harmful algal blooms (cHABs) in lakes and rivers. Therefore, it is very important to monitor their potential uptake by animals and humans as well as their health effects and distribution in affected organs. Herein, the distribution of hepatotoxic peptide microcystin-LR (MC-LR) is investigated in liver tissues of mice gavaged with this most common MC congener. Preliminary matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) imaging experiments performed using a non-automated MALDI matrix deposition device and a MALDI-time-of-flight (TOF) mass spectrometer yielded ambiguous results in terms of MC-LR distribution in liver samples obtained from MC-LR-gavaged mice. The tissue preparation for MALDI-MS imaging was improved by using an automated sprayer for matrix deposition, and liver sections were imaged using an Nd:YAG MALDI laser coupled to a 15 Tesla Fourier-transform ion cyclotron resonance (FT-ICR)-mass spectrometer. MALDI-FT-ICR-MS imaging provided unambiguous detection of protonated MC-LR (calculated m/z 995.5560, z = +1) and the sodium adduct of MC-LR (m/z 1017.5380, z = +1) in liver sections from gavaged mice with great mass accuracy and ultra-high mass resolution. Since both covalently bound and free MC-LR can be found in liver of mice exposed to this toxin, the present results indicate that the distribution of free microcystins in tissue sections from affected organs, such as liver, can be monitored with high-resolution MALDI-MS imaging.
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Woods, Katherine, David Beighton, and John L. Klein. "Identification of the ‘Streptococcus anginosus group’ by matrix-assisted laser desorption ionization – time-of-flight mass spectrometry." Journal of Medical Microbiology 63, no. 9 (September 1, 2014): 1143–47. http://dx.doi.org/10.1099/jmm.0.076653-0.

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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) provides rapid, accurate and cost-effective identification of a range of bacteria and is rapidly changing the face of routine diagnostic microbiology. However, certain groups of bacteria, for example streptococci (in particular viridans or non-haemolytic streptococci), are less reliably identified by this method. We studied the performance of MALDI-TOF MS for identification of the ‘Streptococcus anginosus group’ (SAG) to species level. In total, 116 stored bacteraemia isolates identified by conventional methods as belonging to the SAG were analysed by MALDI-TOF MS. Partial 16S rRNA gene sequencing, supplemented with sialidase activity testing, was performed on all isolates to provide ‘gold standard’ identification against which to compare MALDI-TOF MS performance. Overall, 100 % of isolates were correctly identified to the genus level and 93.1 % to the species level by MALDI-TOF MS. However, only 77.6 % were correctly identified to the genus level and 59.5 % to the species level by a MALDI-TOF MS direct transfer method alone. Use of a rapid in situ extraction method significantly improved identification rates when compared with the direct transfer method (P<0.001). We recommend routine use of this method to reduce the number of time-consuming full extractions required for identification of this group of bacteria by MALDI-TOF MS in the routine diagnostic laboratory. Only 22 % (1/9) of Streptococcus intermedius isolates were reliably identified by MALDI-TOF MS to the species level, even after full extraction. MALDI-TOF MS reliably identifies S. anginosus and Streptococcus constellatus to the species level but does not reliably identify S. intermedius.
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Padilla Jaramillo, Carlos A., Luis M. Díaz Sánchez, Marianny Y. Combariza Montañez, Cristian Blanco Tirado, and Aldo F. Combariza Montañez. "Photon Harvesting Molecules: Ionization Potential from Quantum Chemical Calculations of Phytoplanktonic Pigments for MALDI-MS Analysis." Orinoquia 25, no. 1 (June 16, 2021): 13–23. http://dx.doi.org/10.22579/20112629.676.

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The Ionization Potential (IP) of chemical species is of paramount importance for the Matrix Assisted Laser Desorption/Ionization (MALDI) analyticaltechnique. Specifically, IPs are used in MALDI MS Electron Transfer (ET) as a parameter to select the matrix for a given family of chemical species. We useda quantum chemical methodology to computationally determine IPs for a set of photosensible phytoplanktonic pigments. These calculations could be used as a guide for MALDI matrix selection. IPs were determined using Koopman’s Theorem, via Geometry Optimization and Single Point Energy within the Restricted Closed-Shell Hartree-Fock (RHF) technique. Structures of a twenty-four set of pigments were geometrically optimized, and their IPsdetermined. Calculated IP’s are in close agreement to reported experimental IPs within an average 3.7% absolute error. Structural features of the chemical species studied have a closed relationship with their chemical properties and IP’s. Our results suggest that ET-MALDI matrices such as DCTB (IP = 8.5 eV) and CNPV-OCH3 (IP = 8.3 eV) could be more suitable to analyze these types of chemical species.
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Nie, Shuping, Baoyu Tian, Xiaowei Wang, David H. Pincus, Martin Welker, Kathleen Gilhuley, Xuedong Lu, Yiping W. Han, and Yi-Wei Tang. "Fusobacterium nucleatum Subspecies Identification by Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry." Journal of Clinical Microbiology 53, no. 4 (February 4, 2015): 1399–402. http://dx.doi.org/10.1128/jcm.00239-15.

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We explored the use of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) for identification ofFusobacterium nucleatumsubspecies. MALDI-TOF MS spectra of fiveF. nucleatumsubspecies (animalis,fusiforme,nucleatum,polymorphum, andvincentii) were analyzed and divided into four distinct clusters, including subsp.animalis,nucleatum,polymorphum, andfusiforme/vincentii. MALDI-TOF MS with the modified SARAMIS database further correctly identified 28 of 34F. nucleatumclinical isolates to the subspecies level.
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Pomastowski, Pawel, and Boguslaw Buszewski. "Complementarity of Matrix- and Nanostructure-Assisted Laser Desorption/Ionization Approaches." Nanomaterials 9, no. 2 (February 14, 2019): 260. http://dx.doi.org/10.3390/nano9020260.

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In recent years, matrix-assisted laser desorption/ionization (MALDI) has become the main tool for the study of biological macromolecules, such as protein nano-machines, especially in the determination of their molecular masses, structure, and post-translational modifications. A key role in the classical process of desorption and ionization of the sample is played by a matrix, usually a low-molecular weight weak organic acid. Unfortunately, the interpretation of mass spectra in the mass range of below m/z 500 is difficult, and hence the analysis of low molecular weight compounds in a matrix-assisted system is an analytical challenge. Replacing the classical matrix with nanomaterials, e.g., silver nanoparticles, allows improvement of the selectivity and sensitivity of spectrometric measurement of biologically important small molecules. Nowadays, the nanostructure-assisted laser desorption/ionization (NALDI) approach complements the classic MALDI in the field of modern bioanalytics. In particular, the aim of this work is to review the recent advances in MALDI and NALDI approaches.
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Debeljak, Željko, Ann-Christin Niehoff, Ana Bandjak, Dario Mandić, Bojana Bošnjak, Marija Heffer, Stefan Mrđenović, Ivana Marković, Milorad Zjalić, and Vatroslav Šerić. "MALDI TOF Mass Spectrometry Imaging of Blood Smear: Method Development and Evaluation." International Journal of Molecular Sciences 22, no. 2 (January 8, 2021): 585. http://dx.doi.org/10.3390/ijms22020585.

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The aim of this study was to develop and evaluate matrix assisted LASER desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry imaging (MSI) of blood smear. Integrated light microscope and MALDI IT-TOF mass spectrometer, together with a matrix sublimation device, were used for analysis of blood smears coming from healthy male donors. Different blood plasma removal, matrix deposition, and instrumental settings were evaluated using the negative and positive ionization modes while agreement between the light microscopy images and the lateral distributions of cellular marker compounds served as the MSI quality indicator. Red and white blood cells chemical composition was analyzed using the differential m/z expression. Five seconds of exposure to ethanol followed by the 5 min of 9-aminoacridine or α-cyano-4-hydroxycinnamic acid deposition, together with two sets of instrumental settings, were selected for the MALDI TOF MSI experiments. Application of the thin and transparent matrix layers assured good correspondence between the LASER footprints and the preselected regions of interest. Cellular marker m/z signals coincided well with the appropriate cells. A metabolite databases search using the differentially expressed m/z produced hits which were consistent with the respective cell types. This study sets the foundations for application of blood smear MALDI TOF MSI in clinical diagnostics and research.
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Debeljak, Željko, Ann-Christin Niehoff, Ana Bandjak, Dario Mandić, Bojana Bošnjak, Marija Heffer, Stefan Mrđenović, Ivana Marković, Milorad Zjalić, and Vatroslav Šerić. "MALDI TOF Mass Spectrometry Imaging of Blood Smear: Method Development and Evaluation." International Journal of Molecular Sciences 22, no. 2 (January 8, 2021): 585. http://dx.doi.org/10.3390/ijms22020585.

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The aim of this study was to develop and evaluate matrix assisted LASER desorption ionization (MALDI) time-of-flight (TOF) mass spectrometry imaging (MSI) of blood smear. Integrated light microscope and MALDI IT-TOF mass spectrometer, together with a matrix sublimation device, were used for analysis of blood smears coming from healthy male donors. Different blood plasma removal, matrix deposition, and instrumental settings were evaluated using the negative and positive ionization modes while agreement between the light microscopy images and the lateral distributions of cellular marker compounds served as the MSI quality indicator. Red and white blood cells chemical composition was analyzed using the differential m/z expression. Five seconds of exposure to ethanol followed by the 5 min of 9-aminoacridine or α-cyano-4-hydroxycinnamic acid deposition, together with two sets of instrumental settings, were selected for the MALDI TOF MSI experiments. Application of the thin and transparent matrix layers assured good correspondence between the LASER footprints and the preselected regions of interest. Cellular marker m/z signals coincided well with the appropriate cells. A metabolite databases search using the differentially expressed m/z produced hits which were consistent with the respective cell types. This study sets the foundations for application of blood smear MALDI TOF MSI in clinical diagnostics and research.
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Koudelka, Štěpán, Tereza Gelbíčová, Markéta Procházková, and Renáta Karpíšková. "Lineage and serotype identification of Listeria monocytogenes by matrix-assisted laser desorption ionization-time of flight mass spectrometry." Czech Journal of Food Sciences 36, No. 6 (January 7, 2019): 452–58. http://dx.doi.org/10.17221/87/2018-cjfs.

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The identification of Listeria species, lineages and serotypes remains a crucial issue not only in epidemic surveys, but also in monitoring of the diversity of bacteria in the food chain. The aim of this study was identification of L. monocytogenes strains at lineage and serotype level using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The performance of MALDI-TOF MS was tested to identify L. monocytogenes into two lineages (I and II) and four serotypes (1/2a, 1/2b, 1/2c and 4b) the most commonly found in humans and food. Total of 227 L. monocytogenes strains from different sources were subjected to the study. Some of strains (112) were used for main spectrum profile (MSP) library creation. Other strains of interest (115) were then correctly identified on the lineage level comparing with the library by MALDI-TOF MS analysis using Biotyper (90%) and ClinPro Tools (100%) software. The serotype identification with 55.7% (Biotyper) and 67.8% (ClinPro Tools) accuracy is rather a proof that under given conditions the method has not big potential to be used for serotyping. However, MALDI-TOF MS has a potential to identify lineages of L. monocytogenes of food and human origin.
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Madhavan, Anitha, Arun Sachu, Nandini Sethuraman, Anil Kumar, and Jayalakshmi Vasudevapanicker. "Evaluation of Matrix-assisted laser desorption/ionization Time-of flight Mass spectrometry (MALDI TOF MS) and VITEK 2 in routine microbial identification." Ghana Medical Journal 55, no. 4 (December 1, 2021): 308–10. http://dx.doi.org/10.4314/gmj.v55i4.12.

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Background: Microbial Identification was done by phenotypic methods. VITEK-2 and Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) are now being increasingly used in laboratories.Objectives: To compare and evaluate the usefulness of MALDI-TOF MS and VITEK-2 in routine microbial identification.Methods: The performances of MALDI-TOF MS and VITEK 2 were compared for identifying microorganisms.Results: MALDI- TOF MS and VITEK-2 correctly identified 96 % (96/100) and 97% (97/100) of the isolates upto the genus level.Conclusion: MALDI TOF MS and VITEK -2 gave comparable identification and error rates. The rapid reduction in turnaround time with MALDI TOF is a significant game-changer in the field of clinical microbiology
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Tamma, Pranita D., Kennard Tan, Veronique R. Nussenblatt, Alison E. Turnbull, Karen C. Carroll, and Sara E. Cosgrove. "Can Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF) Enhance Antimicrobial Stewardship Efforts in the Acute Care Setting?" Infection Control & Hospital Epidemiology 34, no. 9 (September 2013): 990–95. http://dx.doi.org/10.1086/671731.

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We evaluated 222 hospitalized patients whose clinical isolates were tested using standard methods and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF). MALDI-TOF could have reduced time to appropriate therapy for 28.8% and 44.6% patients based on the treating physician's choices and stewardship team recommendations, respectively. Clinicians should be aware of scenarios in which MALDI-TOF can optimize antibiotic therapy.
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Nicola, Anthony J., Arkady I. Gusev, and David M. Hercules. "Direct Quantitative Analysis from Thin-Layer Chromatography Plates Using Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry." Applied Spectroscopy 50, no. 12 (December 1996): 1479–82. http://dx.doi.org/10.1366/0003702963904458.

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Direct quantitative analysis using thin-layer chromatography (TLC) coupled with matrix-assisted laser desorption/ionization mass spectrometry (MALDI) has been demonstrated. An internal standard and a data collection protocol were used for analysis directly from TLC plates to compensate for shot-to-shot signal degradation, as well as deviations of analyte and internal standard spatial distributions within the TLC spot. Cocaine hydrochloride was used as a model compound for this study, and cocaine- d3 was used as the internal standard. Quantitative analysis by TLC/MALDI yielded comparable results to those obtained with stainless steel substrates (the standard MALDI method) for point-to-point repeatability, % RSD of the standard curve, and measurement precision. For silica gel and reverse-phase TLC plates, the relative standard deviation of the standard curve slope was better than 3%, the relative standard deviations of the analyte/internal standard intensity ratios ranged from 3.8% to 9.5%, the precision was estimated to be better than 12%, and the detection limits were estimated to be 60 pg for both TLC plate types. Quantitative analysis using stainless steel substrates yielded a lower detection limit than that obtained by TLC/MALDI by a factor of six. Perspectives for improving the detection limits of direct TLC/MALDI quantitative analysis are discussed. Index Headings: MALDI; TLC; Quantification.
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Chen, Xin-Fei, Xin Hou, Meng Xiao, Li Zhang, Jing-Wei Cheng, Meng-Lan Zhou, Jing-Jing Huang, Jing-Jia Zhang, Ying-Chun Xu, and Po-Ren Hsueh. "Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF MS) Analysis for the Identification of Pathogenic Microorganisms: A Review." Microorganisms 9, no. 7 (July 19, 2021): 1536. http://dx.doi.org/10.3390/microorganisms9071536.

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Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been used in the field of clinical microbiology since 2010. Compared with the traditional technique of biochemical identification, MALDI-TOF MS has many advantages, including convenience, speed, accuracy, and low cost. The accuracy and speed of identification using MALDI-TOF MS have been increasing with the development of sample preparation, database enrichment, and algorithm optimization. MALDI-TOF MS has shown promising results in identifying cultured colonies and rapidly detecting samples. MALDI-TOF MS has critical research applications for the rapid detection of highly virulent and drug-resistant pathogens. Here we present a scientific review that evaluates the performance of MALDI-TOF MS in identifying clinical pathogenic microorganisms. MALDI-TOF MS is a promising tool in identifying clinical microorganisms, although some aspects still require improvement.
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Ucal, Yasemin, and Aysel Ozpinar. "Improved spectra for MALDI MSI of peptides using ammonium phosphate monobasic in MALDI matrix." Journal of Mass Spectrometry 53, no. 8 (June 19, 2018): 635–48. http://dx.doi.org/10.1002/jms.4198.

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de Jonker, Maurice, Pim E. G. Leonards, Marja H. Lamoree, and Sicco H. Brandsma. "A Rapid Screening Method for the Detection of Additives in Electronics and Plastic Consumer Products Using AP-MALDI-qTOF-MS." Toxics 11, no. 2 (January 23, 2023): 108. http://dx.doi.org/10.3390/toxics11020108.

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A novel method was developed and optimized for the fast-screening analysis of additives in electronics and plastic consumer products using atmospheric pressure matrix-assisted laser desorption ionization (AP-MALDI) coupled with a high-resolution quadrupole time-of-flight (qTOF) mass spectrometer (MS). To simplify sample preparation and increase sample throughput, an innovative 48 well graphene nanoplatelets (GNP) doped AP-MALDI target plate was developed. The GNP incorporated in the target plate fulfilled the role of the MALDI matrix and, therefore, sample extracts could be directly transferred to the AP-MALDI 48 well target plate and analyzed without a subsequent matrix addition. The homogeneously dispersed and immobilized GNP target plates also provided increased signal intensity and reproducibility. Furthermore, analytical standards of various plastic additives and plastic products with known concentrations of additives were studied to assess the AP-MALDI ionization mechanisms and method capability. The analysis time was 15 s per measurement using an automated sequence. The GNP-doped target plates exhibited high desorption/ionization of low molecular weight molecules (<1000 Da) and can be used in both positive and negative ionization modes. The AP-MALDI-qTOF-MS method was applied to screen for additives in various electronics and plastic consumer products. Suspect screening was performed using a database containing 1366 compounds. A total of 56 additives including antioxidants, flame retardants, plasticizers, UV-stabilizers, and UV-filters were identified (confidence level 4). Identification of certain plastic additives in plastic children’s toys may indicate that they are recycled from waste electronic and electronic equipment (WEEE).
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Westblade, Lars F., Omai B. Garner, Karen MacDonald, Constance Bradford, David H. Pincus, A. Brian Mochon, Rebecca Jennemann, et al. "Assessment of Reproducibility of Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry for Bacterial and Yeast Identification." Journal of Clinical Microbiology 53, no. 7 (April 29, 2015): 2349–52. http://dx.doi.org/10.1128/jcm.00187-15.

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Matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry (MS) has revolutionized the identification of clinical bacterial and yeast isolates. However, data describing the reproducibility of MALDI-TOF MS for microbial identification are scarce. In this study, we show that MALDI-TOF MS-based microbial identification is highly reproducible and can tolerate numerous variables, including differences in testing environments, instruments, operators, reagent lots, and sample positioning patterns. Finally, we reveal that samples of bacterial and yeast isolates prepared for MALDI-TOF MS identification can be repeatedly analyzed without compromising organism identification.
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Tan, Zhi Lei, Yu Qiao Wei, Shuang Liang, Ran Zhang, Miao Liu, and Shi Ru Jia. "Rapid Identification of Microorganisms Isolated from Pickled Vegetables by MALDI-TOF Mass Spectrometry." Advanced Materials Research 712-715 (June 2013): 494–97. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.494.

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Matrix-assisted laser desorption/ionization time-off light mass spectrometry (MALDI-TOF MS) is increasingly used as a microbial diagnostic method for species identification of pathogens. However, MALDI-TOF MS identification of food bacteria was seldom reported. Ten strains isolated from different pickled vegetables were rapid identified by MALDI-TOF MS. The results of MALDI-TOF MS were confirmed by 16S rDNA sequencing method. Different score values in MALDI-TOF MS revealed nineLeuconostoc mesenteroides and oneStaphylococcus.Identification success at the species and genus levels was 90% (9/10) and 100% (10/10), respectively.16S rDNA sequencing results showed that nine stains were identified asLeuconostoc mesenteroides and one wasStaphylococcus saprophyticus.Results obtained demonstrate that MALDI-TOFMS is a promising method for discriminating and identifying food bacteria.
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Le, Hoa Thi, Kyu H. Park, Woong Jung, Hyung Soon Park, and Tae Woo Kim. "Combination of Microwave-Assisted Girard Derivatization with Ionic Liquid Matrix for Sensitive MALDI-TOF MS Analysis of Human Serum N-Glycans." Journal of Analytical Methods in Chemistry 2018 (October 21, 2018): 1–7. http://dx.doi.org/10.1155/2018/7832987.

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We developed a new method for MALDI-TOF MS detection of N-glycans derived from human serum. The synergistic combination of microwave-assisted Girard T derivatization, solid-phase extraction desalting, and an ionic liquid matrix (2, 5-dihydroxybenzoic acid/aniline) (GT-SPE-DHB/An) allowed of more sensitive N-glycans detection than a conventional ionic liquid matrix in MALDI-TOF MS. The superior sensitivity of our method was confirmed by the number of assigned N-glycans in 900–2,000 m/z range. Using our GT-SPE-DHB/An method, we were successfully able to assign 31 glycans. However, with the established method, i.e., DHB/An method, only 15 glycans were assigned. To the best of our knowledge, this GT-SPE-DHB/An method is the first to combine cationic derivatization of N-glycan and ionic liquid matrix for N-glycan analysis in MALDI-TOF MS.
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Setz, Patrick D., and Richard Knochenmuss. "Exciton Mobility and Trapping in a MALDI Matrix." Journal of Physical Chemistry A 109, no. 18 (May 2005): 4030–37. http://dx.doi.org/10.1021/jp050622c.

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Aerni, Hans-Rudolf, Dale S. Cornett, and Richard M. Caprioli. "Automated Acoustic Matrix Deposition for MALDI Sample Preparation." Analytical Chemistry 78, no. 3 (February 2006): 827–34. http://dx.doi.org/10.1021/ac051534r.

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Murphy, Robert C., Joseph A. Hankin, Robert M. Barkley, and Karin A. Zemski Berry. "MALDI imaging of lipids after matrix sublimation/deposition." Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids 1811, no. 11 (November 2011): 970–75. http://dx.doi.org/10.1016/j.bbalip.2011.04.012.

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Slyundina, M. S., N. Yu Polovkov, R. S. Borisov, and V. G. Zaikin. "Tryptamine: a Reactive Matrix for MALDI Mass Spectrometry." Journal of Analytical Chemistry 72, no. 13 (December 2017): 1295–99. http://dx.doi.org/10.1134/s106193481713010x.

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Chang, Wei Chao, Ling Chu Lora Huang, Yi-Sheng Wang, Wen-Ping Peng, Huan Cheng Chang, Nien Yeen Hsu, Wen Bin Yang, and Chung Hsuan Chen. "Matrix-assisted laser desorption/ionization (MALDI) mechanism revisited." Analytica Chimica Acta 582, no. 1 (January 2007): 1–9. http://dx.doi.org/10.1016/j.aca.2006.08.062.

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48

Madeira, Paulo J. Amorim, and M. Helena Florêncio. "Flavonoid-matrix cluster ions in MALDI mass spectrometry." Journal of Mass Spectrometry 44, no. 7 (July 2009): 1105–13. http://dx.doi.org/10.1002/jms.1588.

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Schinkovitz, Andreas, and Pascal Richomme. "Usnic acid and its versatility as MALDI matrix." Journal of Mass Spectrometry 50, no. 1 (January 2015): 270–74. http://dx.doi.org/10.1002/jms.3513.

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Hanton, Scott D., and Kevin G. Owens. "Using MESIMS to analyze polymer MALDI matrix solubility." Journal of the American Society for Mass Spectrometry 16, no. 7 (July 2005): 1172–80. http://dx.doi.org/10.1016/j.jasms.2005.03.013.

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