Artículos de revistas: "IR/THz simultaneous spectroscopy"

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Chupas, Peter, Karena Chapman, Kevin Beyer, Olaf Borkiewicz y Haiyan Zhao. "Simultaneous infrared spectroscopy and X-ray PDF measurements". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 de agosto de 2014): C1179. http://dx.doi.org/10.1107/s2053273314088202.

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Combining insights from diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) and X-ray pair distribution function (PDF) analysis has the potential to provide deeper insight into complex materials systems under reactive conditions, including heterogeneous catalysts and host-guest systems. We have developed instrumentation and non-ambient reaction cells that enable combined PDF-IR studies without compromise to either measurement. Through careful selection of the IR spectrometer and optics, the IR instrument and reaction cell were adapted to allow angular dispersive X-ray measurements without change to the active IR components, resulting in IR data that are entirely uncompromised. The associated PDF and diffraction data are shown to be of comparable quality and resolution to standard geometry PDF/diffraction measurements. We have demonstrated this approach through the study of desorption of coordinated and non-coordinated guests from the nanoporous Prussian blue analogue MnII3[CoIII(CN)6]2(H2O)6·x{H2O}. The combined data shows how the release of guests from different sites is coupled to structural relaxation of the framework. We will also discus recent results where we have extended the approach to the study of zeolite catalysts.

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Śliwińska, Smolinski y Kucharski. "Simultaneous Analysis of Heavy Metal Concentration in Soil Samples". Applied Sciences 9, n.º 21 (4 de noviembre de 2019): 4705. http://dx.doi.org/10.3390/app9214705.

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The application of Fourier transform infrared spectroscopy to the simultaneous analysis of heavy metal concentration in soil samples was demonstrated in this paper. Two spectral techniques, namely, attenuated total reflectance (ATR) and diffuse reflectance (DRIFT), were applied and the whole infrared spectral region, i.e., far IR, mid IR, and near IR were considered in this work. Spectral data with reference to the results of laboratory analysis enabled the development of calibration partial least squares (PLS) models. The PLS models for the ATR near IR were characterized by a good fit and good prediction abilities. According to the results obtained, the most accurate description and prediction were realized in the case of mid/far and near IR for the mercury and nickel concentration in soil. Application of far IR slightly improved the prediction possibilities of the model. The construction of PLS models based on the Fourier-transform infrared (FT-IR) spectra enables the perception of FT-IR spectroscopy as a supplementary method that is useful in the estimation and monitoring of the contamination level in soils.

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Pelletier, Isabelle, Christian Pellerin, D. Bruce Chase y John F. Rabolt. "New Developments in Planar Array Infrared Spectroscopy". Applied Spectroscopy 59, n.º 2 (febrero de 2005): 156–63. http://dx.doi.org/10.1366/0003702053085043.

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A planar array infrared (PA-IR) spectrograph offers several advantages over other infrared approaches, including high acquisition rate and sensitivity. However, it suffers from some important drawbacks, such as a limited spectral range and a significant curvature of the recorded spectral images, which still need to be addressed. In this article, we present new developments in PA-IR spectroscopy that overcome these drawbacks. First, a data processing method for the correction of the curvature observed in the spectral images has been developed and refined. In addition, a dual-beam instrument that allows the simultaneous recording of two independent spectral images has been developed. These two improvements have been combined to demonstrate the real-time background correction capability of PA-IR instruments. Finally, the accessible spectral range of the PA-IR spectrograph has been extended to cover simultaneously the methylene stretching (3200–2800 cm−1) and the fingerprint (2000–1000 cm−1) spectral regions.

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Zhu, Qianqian, Rui Zhou, Jun Liu, Jianzhong Sun y Qianqian Wang. "Recent Progress on the Characterization of Cellulose Nanomaterials by Nanoscale Infrared Spectroscopy". Nanomaterials 11, n.º 5 (20 de mayo de 2021): 1353. http://dx.doi.org/10.3390/nano11051353.

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Researches of cellulose nanomaterials have seen nearly exponential growth over the past several decades for versatile applications. The characterization of nanostructural arrangement and local chemical distribution is critical to understand their role when developing cellulose materials. However, with the development of current characterization methods, the simultaneous morphological and chemical characterization of cellulose materials at nanoscale resolution is still challenging. Two fundamentally different nanoscale infrared spectroscopic techniques, namely atomic force microscope based infrared spectroscopy (AFM-IR) and infrared scattering scanning near field optical microscopy (IR s-SNOM), have been established by the integration of AFM with IR spectroscopy to realize nanoscale spatially resolved imaging for both morphological and chemical information. This review aims to summarize and highlight the recent developments in the applications of current state-of-the-art nanoscale IR spectroscopy and imaging to cellulose materials. It briefly outlines the basic principles of AFM-IR and IR s-SNOM, as well as their advantages and limitations to characterize cellulose materials. The uses of AFM-IR and IR s-SNOM for the understanding and development of cellulose materials, including cellulose nanomaterials, cellulose nanocomposites, and plant cell walls, are extensively summarized and discussed. The prospects of future developments in cellulose materials characterization are provided in the final part.

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Sullivan, David H., W. Curtis Conner y Michael P. Harold. "Surface Analysis with FT-IR Emission Spectroscopy". Applied Spectroscopy 46, n.º 5 (mayo de 1992): 811–18. http://dx.doi.org/10.1366/0003702924124844.

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The technique of infrared emission spectroscopy (IRES) is reviewed and further examined in this study as a surface analysis tool. A system has been designed which allows simultaneous kinetic and in situ infrared emission analysis of catalyst surfaces. IRES spectra of several gas mixture/solid systems are obtained in order to examine sample preparation and spectra processing issues; these systems include Pt/Al2O3 exposed to CO and CO-NO mixtures, an oxidized copper plate, and a zeolite exposed to inert atmospheres. For the temperature range of importance to catalysis (300–600 K), IRES is limited to frequencies less than 2500 cm−1. However, IRES is especially well suited for studying solid-state vibrational modes (<1000 cm−1). Moreover, IRES allows catalyst samples to be studied without dilution or extensive sample preparation. The thin samples required for IRES make it possible to study both surface adsorbate and the solid-state lattice vibrations simultaneously. This information can provide useful insight into the interpretation of kinetic data of reactions on metal oxide catalysts. However, samples which are too thick or are supported on a high-emissivity surface will not yield satisfactory spectra. Two correction techniques are examined which reduce background and sample-reflectance effects in the emission spectra. Some of the IRES data are compared to the corresponding spectra obtained by transmission and diffuse-reflectance spectroscopy. IRES is shown to be competitive with these more popular techniques for IR surface analysis.

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Beyer, Kevin A., Haiyan Zhao, Olaf J. Borkiewicz, Mark A. Newton, Peter J. Chupas y Karena W. Chapman. "Simultaneous diffuse reflection infrared spectroscopy and X-ray pair distribution function measurements". Journal of Applied Crystallography 47, n.º 1 (7 de diciembre de 2013): 95–101. http://dx.doi.org/10.1107/s1600576713028410.

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Combining insights from diffuse reflection infrared Fourier transform spectroscopy and X-ray pair distribution function (PDF) analysis has the potential to deepen our understanding of complex materials systems including heterogeneous catalysts and host–guest systems. This article describes the development of instrumentation and non-ambient reaction cells that enable combined PDF–IR studies without compromise to either measurement. Through careful selection of the IR spectrometer and optics, the IR instrument and reaction cell were adapted to allow angular dispersive X-ray measurements without change to the active IR components. The PDF and diffraction data obtained with this experimental configuration are shown to be of similar quality and resolution to standard capillary-based measurements. Simultaneous combined measurements are demonstrated for desorption of guests from within a Prussian blue analog.

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Liu, Kan-Zhi, R. Anthony Shaw, Angela Man, Thomas C. Dembinski y Henry H. Mantsch. "Reagent-free, Simultaneous Determination of Serum Cholesterol in HDL and LDL by Infrared Spectroscopy". Clinical Chemistry 48, n.º 3 (1 de marzo de 2002): 499–506. http://dx.doi.org/10.1093/clinchem/48.3.499.

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Abstract Background: The purpose of this study was to assess the feasibility of infrared (IR) spectroscopy for the simultaneous quantification of serum LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) concentrations. Methods: Serum samples (n = 90) were obtained. Duplicate aliquots (5 μL) of the serum specimens were dried onto IR-transparent barium fluoride substrates, and transmission IR spectra were measured for the dry films. In parallel, the HDL-C and LDL-C concentrations were determined separately for each specimen by standard methods (the Friedewald formula for LDL-C and an automated homogeneous HDL-C assay). The proposed IR method was then developed with a partial least-squares (PLS) regression analysis to quantitatively correlate IR spectral features with the clinical analytical results for 60 randomly chosen specimens. The resulting quantification methods were then validated with the remaining 30 specimens. The PLS model for LDL-C used two spectral ranges (1700–1800 and 2800–3000 cm−1) and eight PLS factors, whereas the PLS model for HDL-C used three spectral ranges (800–1500, 1700–1800, and 2800–3500 cm−1) with six factors. Results: For the 60 specimens used to train the IR-based method, the SE between IR-predicted values and the clinical laboratory assays was 0.22 mmol/L for LDL-C and 0.15 mmol/L for HDL-C (r = 0.98 for LDL-C; r = 0.91 for HDL-C). The corresponding SEs for the test spectra were 0.34 mmol/L (r = 0.96) and 0.26 mmol/L (r = 0.82) for LDL-C and HDL-C, respectively. The precision for the IR-based assays was estimated by the SD of duplicate measurements to be 0.11 mmol/L (LDL-C) and 0.09 mmol/L (HDL-C). Conclusions: IR spectroscopy has the potential to become the clinical method of choice for quick and simultaneous determinations of LDL-C and HDL-C.

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Hazel, G., F. Bucholtz, I. D. Aggarwal, G. Nau y K. J. Ewing. "Multivariate Analysis of Mid-IR FT-IR Spectra of Hydrocarbon-Contaminated Wet Soils". Applied Spectroscopy 51, n.º 7 (julio de 1997): 984–89. http://dx.doi.org/10.1366/0003702971941359.

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This article describes a series of mid-IR FT-IR reflectance spectroscopy measurements of hydrocarbon-contaminated wet soils. The eventual goal of this work is the development of an analysis tool suitable for real-time in situ underground measurements where a suitable reference spectrum is not available. Multivariate analysis of the resulting spectral data indicates that the strongly varying wet soil matrix and the absence of a suitable reference spectrum in the field do not render this measurement technique unfeasible as a means of realizing remote in situ chemical detection in wet soils. It was also observed that simultaneous quantification of moisture content and identification of soil composition may be achieved. These results have important applications to in situ site characterization for environmental cleanup and soil characterization for construction planning.

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Shaw, R. Anthony, Steven Kotowich, Michael Leroux y Henry H. Mantsch. "Multianalyte Serum Analysis Using Mid-Infrared Spectroscopy". Annals of Clinical Biochemistry: International Journal of Laboratory Medicine 35, n.º 5 (septiembre de 1998): 624–32. http://dx.doi.org/10.1177/000456329803500505.

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This study assesses the potential for using mid-infrared (mid-IR) spectroscopy of dried serum films as the basis for the simultaneous quantitation of eight serum analytes: Total protein, albumin, triglycerides, cholesterol, glucose, urea, creatinine and uric acid. Infrared transmission spectra were acquired for 300 serum samples, each analysed independently using accepted reference clinical chemical methods. Quantitation methods were based upon the infrared spectra and reference analyses for 200 specimens, and the models validated using the remaining 100 samples. Standard errors in the IR-predicted analyte levels (Sy/x) were 2.8 g/L (total protein), 2.2 g/L (albumin), 0.23 mmol/L (triglycerides), 0.28 mmol/L (cholesterol), 0.41 mmol/L (glucose) and 1.1 mmol/L for urea, with correlation coefficients (IR vs reference analyses) of 0.95 or better. The IR method emerged to be less suited for creatinine (S y/ x = μmol/L) and uric acid (S y/x = 140 μmol/L) due to the relatively low concentrations typical of these analytes.

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Manning, Christopher J. y Peter R. Griffiths. "Step-Scanning Interferometer with Digital Signal Processing". Applied Spectroscopy 47, n.º 9 (septiembre de 1993): 1345–49. http://dx.doi.org/10.1366/0003702934067630.

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A novel step-scan FT-IR spectrometer incorporating a digital signal processor for demodulation of the detector signal is described. The potential advantages of this method of signal processing are discussed and illustrated. The instrument is based on a commercial cube-corner interferometer which has been modified by replacement of the drive motor with a stepper motor-micrometer and piezoelectric transducer combination. The interferometer retardation is feedback controlled by a 486–50 personal computer, which also controls the digital signal processor and collects spectral data. More than one phase modulation frequency can be imposed simultaneously, allowing for a multiplex advantage in photoacoustic depth profiling. Digital signal processing allows for simultaneous demodulation of multiple frequencies which would normally require several lock-in amplifiers. Data that illustrate the feasibility of these concepts are presented. The suitability of this instrument for double-modulation step-scan FT-IR measurements such as polymer stretching and electrochemically modulated step-scan FT-IR is also discussed.

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Alam, M. M., S. M. S. Islam, S. M. M. Rahman y M. M. Rahman. "Simultaneous Preparation of Facial and Meridional Isomer of Cobalt-Amino Acid Complexes and their Characterization". Journal of Scientific Research 2, n.º 1 (29 de diciembre de 2009): 91–98. http://dx.doi.org/10.3329/jsr.v2i1.2032.

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Preparation and characterization of various complexes of cobalt (III)-amino acid system, especially cobalt (III) glycinato and cobalt (III) alaninato complexes are reported. The identification of the various isomers of these complexes is also reported. The various isomers are separated from their mixture by fractional crystallization. Each of these complexes has been characterized by observing physical characteristics, chemical analysis, UV-visible spectroscopy and IR-spectroscopy. The direct impact of geometry of the complexes to IR stretching frequencies and UV-visible spectral data of amino and carboxyl group in the complexes provided sufficient information about the geometry. A prediction about the geometries of the synthesized has also been focused. Keywords: Cobalt; Amino acid; Isomers; UV-visible; IR. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i1.2032 J. Sci. Res. 2 (1), 91-98 (2010)

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Tarach, Karolina A., Anna K. Walczyk, Agata Kordek, Oliwia Rogala y Kinga Góra-Marek. "Silver-Loaded Chabazite in Ethanol-to-Hydrocarbon Process—Operando FT-IR and UV-Vis Spectroscopic Studies". Molecules 29, n.º 6 (8 de marzo de 2024): 1207. http://dx.doi.org/10.3390/molecules29061207.

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The ethanol dehydration process is studied regarding protonic and Ag-loaded chabazite zeolite in advanced FT-IR and UV-vis operando spectroscopic studies with simultaneous mass spectroscopy and gas chromatography analyses of products. The spectroscopic investigation provides information on the species formed on the surface of catalysts, while mass spectrometry and gas chromatography methods identify the desorbed products. These studies are also supported by spectroscopic, chromatographic, and thermogravimetric analyses of coke species formed over the catalyst’s surface during ethanol conversion. The Ag-chabazite catalyst shows higher selectivity for ethylene and propylene; the slower formation of coke species; and, thus, a longer lifetime.

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Blanco, M., J. Coello, H. Iturriaga, S. Maspoch y E. Bertran. "Simultaneous Determination of Rubber Additives by FT-IR Spectrophotometry with Multivariate Calibration". Applied Spectroscopy 49, n.º 6 (junio de 1995): 747–53. http://dx.doi.org/10.1366/0003702953964453.

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A new method for the simultaneous determination of vulcanized rubber additives by Fourier transform infrared (FT-IR) spectrophotometry using partial least-squares regression (PLSR) for multivariate calibration was developed. The effect of various wavenumber ranges and the use of the absorbance and first-derivative spectral modes on performance were studied by applying the method to three different sample batches containing several additives in different proportions, all of which were resolved with satisfactory results.

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Lanzarotta, Adam, Travis Falconer, Heather McCauley, Lisa Lorenz, Douglas Albright, John Crowe y JaCinta Batson. "Simultaneous Orthogonal Drug Detection Using Fully Integrated Gas Chromatography with Fourier Transform Infrared Detection and Mass Spectrometric Detection". Applied Spectroscopy 71, n.º 5 (1 de octubre de 2016): 1050–59. http://dx.doi.org/10.1177/0003702816668534.

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Analytes that co-elute and yield nearly identical electron ionization (EI) mass spectra, as well as analytes that yield non-specific EI fragmentation patterns, have been identified using fully integrated gas chromatography with direct deposit Fourier transform infrared detection and mass spectrometric detection (GC/FT-IR/MS). While the IR detector proved to be more selective for identifying analytes such as synthetic cannabinoids and weight loss drugs, it was limited by a relatively high detection limit of 8.4 parts per million (ppm) for non-targeted identification of sibutramine based on a single injection but was reduced to 840 parts per billion (ppb) for targeted identification of sibutramine by redepositing ten injections along the same track. The MS detector was less selective for identifying these analytes but yielded non-targeted and targeted detection limits of approximately 84 ppb and 8.4 ppb, respectively, which corresponded to a 100-fold advantage compared to the IR detector. Overall, the results of this study demonstrate that the advantages of each detector compensate for the limitations of the other, which allows a wider range of analytes and concentrations to be examined using a fully integrated GC/FT-IR/MS instrument compared to what can be examined using GC/IR or GC/MS independently. Not only does this approach reduce consumption of laboratory resources and time, it provides IR and MS information on the same sample, which is important for forensic analyses that require data from two or more orthogonal techniques to make an identification.

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Bhargava, Rohit y Ira W. Levin. "Time-Resolved Fourier Transform Infrared Spectroscopic Imaging". Applied Spectroscopy 57, n.º 4 (abril de 2003): 357–66. http://dx.doi.org/10.1366/00037020360625880.

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Fourier transform infrared (FT-IR) imaging allows simultaneous spectral characterization of large spatial areas due to its multichannel detection advantage. The acquisition of large amounts of data in the multichannel configuration results, however, in a poor temporal resolution of sequentially acquired data sets, which limits the examination of dynamic processes to processes that have characteristic time scales of the order of minutes. Here, we introduce the concept and instrumental details of a time-resolved infrared spectroscopic imaging modality that permits the examination of repetitive dynamic processes whose half-lives are of the order of milliseconds. As an illustration of this implementation of step-scan FT-IR imaging, we examine the molecular responses to external electric-field perturbations of a microscopically heterogeneous polymer–liquid crystal composite. Analysis of the spectroscopic data using conventional univariate and generalized two-dimensional (2D) correlation methods emphasizes an additional capability for accessing of simultaneous spatial and temporal chemical measurements of molecular dynamic processes.

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Zhang, Lizhong, James E. Franke, Thomas M. Niemczyk y David M. Haaland. "Optimized External IR Reflection Spectroscopy for Quantitative Determination of Borophosphosilicate Glass Parameters". Applied Spectroscopy 51, n.º 2 (febrero de 1997): 259–64. http://dx.doi.org/10.1366/0003702971940161.

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Infrared (IR) external reflection spectroscopy has been optimized for the quantitative determination of composition and film thickness of borophosphosilicate glass (BPSG) deposited on silicon wafer substrates. The precision of the partial least-squares calibrations for boron and phosphorus contents and thin-film thickness were measured as the cross-validated standard error of prediction statistic. The results showed that BPSG IR reflection spectra collected over a wide range of incident IR radiation angles (15°, 25°, 45°, and 60°) can be used for the simultaneous quantification of these three BPSG parameters. When high angles of incidence were employed, the measurement was found to be more sensitive to small errors in the angle of incidence. The polarization state of the incident IR radiation did not noticeably affect the prediction of the three calibrated BPSG parameters. The results achieved in this study provide guidelines for at-line process monitoring and quality control of BPSG thin films used in the fabrication of microelectronic devices. Index Headings: IR reflection; Multivariate calibration; Partial least-squares

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Aykas, Didem P. y Luis Rodriguez-Saona. "What’s in Your Fruit Juice?—Rapid Quality Screening Based on Infrared (FT-IR) Spectroscopy". Applied Sciences 14, n.º 4 (19 de febrero de 2024): 1654. http://dx.doi.org/10.3390/app14041654.

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Fruit juices (FJ) have gained widespread global consumption, driven by their perceived health benefits. The accuracy of nutrition information is essential for consumers assessing FJ quality, especially with increasing concerns about added sugars and obesity risk. Conversely, ascorbic acid (Vitamin C), found in nature in many fruits and vegetables, is often lost due to its susceptibility to light, air, and heat, and it undergoes fortification during FJ production. Current analytical methods for determining FJ components are time-consuming and labor-intensive, prompting the need for rapid analytical tools. This study employed a field-deployable portable FT-IR device, requiring no sample preparation, to simultaneously predict multiple quality traits in 68 FJ samples from US markets. Using partial least square regression (PLSR) models, a strong correlation (RCV ≥ 0.93) between FT-IR predictions and reference values was obtained, with a low standard error of prediction. Remarkably, 21% and 37% of FJs deviated from nutrition label values for sugars and ascorbic acid, respectively. Portable FT-IR devices offer non-destructive, simultaneous, simple, and high-throughput approaches for chemical profiling and real-time prediction of sugars and acid levels in FJs. Their handiness and ruggedness can provide food processors with a valuable “out-of-the-laboratory” analytical tool.

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Han, Liuyang, Xiangna Han, Guoqing Liang, Xingling Tian, Fang Ma, Suqin Sun, Yafang Yin, Guanglan Xi y Hong Guo. "Even Samples from the Same Waterlogged Wood Are Hygroscopically and Chemically Different by Simultaneous DVS and 2D COS-IR Spectroscopy". Forests 14, n.º 1 (22 de diciembre de 2022): 15. http://dx.doi.org/10.3390/f14010015.

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Waterlogged archaeological wood samples may degrade during long-term immersion in microbial-activity environments, which causes its biodegradation. Simultaneous dynamic vapor sorption (SDVS) and two-dimensional correlation infrared (2D COS-IR) spectroscopy reveal the degradation inhomogeneity of waterlogged fir wood from the Shengbeiyu shipwreck. The waterlogged and reference wood exhibit type II sorption isotherms. The equilibrium moisture contents of waterlogged archaeological fir wood from a decay region (WFD) were 22.5% higher than those of waterlogged archaeological fir wood from a sound region (WFS). WFD exhibits a higher measurable sorption hysteresis than WFS, implying greater variation in the surface moisture content in the WFD region compared to the WFS region, which may compromise the dimensional stability of the shipwreck. 2D COS-IR spectra confirmed the inhomogeneous degradation of the waterlogged wood via numerous mechanisms. The efficacy of SDVS and 2D COS-IR spectroscopy in the evaluation of the degradation state of waterlogged wood was demonstrated. This study verifies the existence of hygroscopic and chemical differences between visually similar samples from the same shipwreck.

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R. Delgado, Montserrat. "Structure and Stability of Gas Adsorption Complexes in Periodic Porous Solids as Studied by VTIR Spectroscopy: An Overview". Applied Sciences 10, n.º 23 (30 de noviembre de 2020): 8589. http://dx.doi.org/10.3390/app10238589.

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Variable-temperature infrared (VTIR) spectroscopy is an instrumental technique that enables structural characterization of gas-solid adsorption complexes by analysis of meaningful vibrational modes, and simultaneous determination of the standard enthalpy change (ΔH0) involved in the gas adsorption process, which allows one to quantify the stability of the corresponding complex. This is achieved by a van’t Hoff analysis of a set of IR spectra recorded over a sufficiently large temperature range. Herein, the use of this versatile spectroscopic technique is demonstrated by reviewing its application to the study of carbon monoxide, carbon dioxide and dinitrogen adsorption on several (alkaline) zeolites, which can be regarded as the archetype of periodic porous solids.

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Gokus, Tobias. "Nano-FTIR Correlation Nanoscopy for Organic and Inorganic Material Analysis". ECS Meeting Abstracts MA2022-01, n.º 7 (7 de julio de 2022): 622. http://dx.doi.org/10.1149/ma2022-017622mtgabs.

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Significance: Correlation scanning probe techniques to complement nanoscale IR measurements for next generation sample characterization Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is a scanning probe approach to optical microscopy and spectroscopy, bypassing the ubiquitous diffraction limit of light to achieve a spatial resolution below 20 nanometers. s-SNOM employs the strong confinement of light at the apex of a sharp metallic atomic force microscopy (AFM) tip to create a nanoscale optical hot-spot. Analyzing the scattered light from the tip enables the extraction of the optical properties of the sample directly below the tip and yields nanoscale resolved images simultaneous to topography [1]. In addition, the technology has been advanced to enable Fourier-Transform Infrared Spectroscopy on the nanoscale (nano-FTIR) [2] using broadband radiation from the visible spectral range to THz frequencies. Recently, the combined analysis of complex nanoscale material systems by correlating near-field optical data with information obtained by other scanning probe microscopy (SPM)-based measurement methodologies has gained significant interest. For example, the material-characteristic nano-FTIR spectra of a phase-separated polystyrene/low-density polyethylene (PS/LDPE) polymer blend verifies sharp material interfaces by measuring a line profile across a ca. 1 μm sized LDPE island. Near-field reflection/absorption imaging at 1500cm-1 of the ca. 50nm thin film allows to selectively highlight the distribution of PS in the blend and simultaneously map the mechanical properties like adhesion of the different materials [3,4]. Further, we present results that correlate the near-field optical response of semiconducting samples like graphene (2D) or functional SRAM devices (3D) in different frequency ranges (mid-IR & THz) to Kelvin Probe Force Microscopy (KPFM) measurements. Thus, s-SNOM systems represent an ideal platform to gain novel insights into complex material systems by different near-field and AFM-based method. [1] F. Keilmann, R. Hillenbrand, Phil. Trans. R. Soc. Lond. A 362, 787 (2004). [2] F. Huth, et al., Nano Lett. 12, 3973 (2012). [3] B. Pollard, et al., Beilstein J. of Nanotechn. 7, 605 (2016). [4] I. Amenabar, et al., Nature Commun. 8, 14402 (2017).

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Wang, Dun Jia, Yan Fang Kang y Ben Po Xu. "Preparation and Thermal Decomposition of the Polyoxometalate Complexes of Ciprofloxacin with H_nXW₁₂O₄₀ (X=B, Si, P)". Advanced Materials Research 335-336 (septiembre de 2011): 1075–78. http://dx.doi.org/10.4028/www.scientific.net/amr.335-336.1075.

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The polyoxometalate complexes of ciprofloxacin with HnXW12O40(X=B, Si, P) were prepared from ciprofloxacin hydrochloride and HnXW12O40·nH2O (X=B, Si, P) in aqueous solution, and characterized by elemental analysis, IR spectra and TG-DTA. The IR spectrum confirmed the presence of Keggin-type anion of heteropoly acids and the characteristic functional group of ciprofloxacin after the polyoxometalate complexes are formed. The TG/DTA curves showed that their thermal decomposition was a more-steps process consisting of simultaneous processes involving also Keggin anion. The residue of decomposition is a mixture of WO3and B2O3, SiO2or P2O5, confirmed by X-ray diffraction and IR spectroscopy. And the possible thermal decomposition mechanisms of the complexes are proposed.

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Ruiz, Y. P., M. F. Ferrão, M. B. Cardoso, E. A. Moncada y J. H. Z. dos Santos. "Structural discrimination of nanosilica particles and mixed-structure silica by multivariate analysis applied to SAXS profiles in combination with FT-IR spectroscopy". RSC Advances 6, n.º 76 (2016): 72306–16. http://dx.doi.org/10.1039/c6ra03306g.

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New methodology to quickly identify changes in the structural properties of mesoporous silica materials through simultaneous multivariate analyses applied to techniques with different principles as SAXS curves and FT-IR spectra.

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Cronin, J. T. y T. B. Brill. "Thermal Decomposition of Energetic Materials 26. Simultaneous Temperature Measurements of the Condensed Phase and Rapid-Scan FT-IR Spectroscopy of the Gas Phase at High Heating Rates". Applied Spectroscopy 41, n.º 7 (septiembre de 1987): 1147–51. http://dx.doi.org/10.1366/0003702874447626.

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Rapid-scan infrared spectroscopy (RSFT-IR) with better than 100-ms temporal resolution has been used to quantify the gas decomposition products of energetic materials in real time at various heating rates up to 800°C/s and under buffer gas pressures of 1 to 1000 psi. A new method is described that permits simultaneous real-time recording of the temperature of the condensed phase and of the IR spectra of the gaseous products under the above conditions. Endothermic and exothermic events in the condensed phase can now be correlated with the evolved gases under conditions approaching those of combustion. The design and procedure for using the cell are given and are applied to the thermolysis of 1,7-diazido-2,4,6-trinitro-2,4,6-triazaheptane (DATH) and pentaery-thrityltetrammonium nitrate (PTTN).

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Fernandez Peña, Ivan, Axayacatl Alvarado Palacios, Enrique Barrera Calva, Jose Antonio Calderón Arenas, Manuel García Hipolito, Ciro Falcony Guajardo, Rogelio Fragoso, Gilberto Alarcón Flores, Cruz Paredes Sanchez y Miguel Angel Aguilar Frutis. "Spray-pyrolyzed Al2O3-Ag Nano-Cermets coatings for solar absorbers". Revista Mexicana de Física 64, n.º 4 (28 de junio de 2018): 392. http://dx.doi.org/10.31349/revmexfis.64.392.

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In this work, it is shown the feasibility for obtaining silver nanoparticles by ultrasonic spray pyrolysis and their simultaneous incorporation during deposition of thin layers of aluminum oxide to get a Cermet coating of Al2O3-Ag. The synthesis of these Cermets was achieved on the basis of both the simultaneous pyrolysis of silver nitrate and aluminum acetylacetonate on different substrates: Quartz, glass, crystalline silicon (c-Si), and titanium at temperatures of 500, 550 and 600 °C. The optical and structural properties of the Cermets were studied by Scanning Electron Microscopy, Atomic Force Microscopy, X-ray diffraction, UV-vis, UV-vis-IR and FT-IR spectroscopies. UV-Vis spectroscopy showed that the intensity of the absorption peak (plasmon) was limited to the concentration of silver nitrate, and it shifted toward shorter wavelengths with the decrease in the size of the Ag nanoparticles inside the Cermets. The plasmon position of Ag nanoparticles in the different samples was found to be centered at 504 nm, 506 nm, 497 nm and 475 nm for samples deposited with 0.1 mol, 0.05 mol, 0.02 mol, and 0.01 mol of Ag(NO3), respectively. The shape of the Ag nanoparticles was approximately spherical, ranging from 4 nm to 35 nm, and their concentration was proportional to the concentration of Ag(NO3) included in the spray solution. By means of the UV-Vis Spectroscopy-IR and FT-IR, in the best of cases, a solar absorptance of 0.83 and an infrared thermal emittance of 0.14, for a sample of Al2O3-Ag prepared with 0.1 mol of Ag(NO3) in the precursor solution, were obtained.

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25

Martínez-Romo, A., R. González-Mota, J. J. Soto-Bernal y I. Rosales-Candelas. "LDPE Oxidation by CO2 Laser Radiation (10.6 µm)". International Journal of Polymer Science 2018 (2018): 1–5. http://dx.doi.org/10.1155/2018/5150673.

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Thermooxidation of LDPE films by CO2 laser radiation, 10.6 μm, was characterized by Fourier transform infrared spectroscopy with attenuated total reflectance (FTIR-ATR). The formation of carbonyl and hydroxyl functional groups onto LDPE films was dependent on the fluency of CO2 laser. IR absorption of vinyl groups and C-O bond present in alcohols showed a decrease and an increase, respectively, indicating that CO2 laser radiation causes simultaneous formation and accumulation of hydroperoxides in LDPE films; furthermore, crystallinity of LDPE films irradiated with CO2 tends to increase. So, CO2 laser radiation is able to oxidize the LDPE films, obtaining a PE with similar spectroscopic properties to that of PE-BIO by a physical process.

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26

Wei, Qianhe, Bincheng Li, Jing Wang, Binxing Zhao y Ping Yang. "Impact of Residual Water Vapor on the Simultaneous Measurements of Trace CH4 and N2O in Air with Cavity Ring-Down Spectroscopy". Atmosphere 12, n.º 2 (6 de febrero de 2021): 221. http://dx.doi.org/10.3390/atmos12020221.

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Methane (CH4) and nitrous oxide (N2O) are among the most important atmospheric greenhouse gases. A gas sensor based on a tunable 7.6 μm continuous-wave external-cavity mode-hop-free (EC-MHF) quantum cascade laser (from 1290 to 1350 cm−1) cavity ring-down spectroscopy (CRDS) technique was developed for the simultaneous detection of CH4 and N2O in ambient air with water vapor (H2O) mostly removed via molecular sieve drying to minimize the impact of H2O on the simultaneous measurements. Still, due to the broad and strong absorption spectrum of H2O in the entire mid-infrared (mid-IR) spectral range, residual H2O in the dried ambient air due to incomplete drying and leakage, if not properly accounted for, could cause a significant influence on the measurement accuracy of the simultaneous CH4 and N2O detection. In this paper, the impact of residual H2O on the simultaneous CH4 and N2O measurements were analyzed by comparing the CH4 and N2O concentrations determined from the measured spectrum in the spectral range from 1311 to 1312.1 cm−1 via simultaneous CH4 and N2O measurements and that determined from the measured spectrum in the spectral range from 1311 to 1313 cm−1 via simultaneous CH4, N2O, and H2O measurements. The measured dependence of CH4 and N2O concentration errors on the simultaneously determined H2O concentration indicated that the residual H2O caused an under-estimation of CH4 concentration and over-estimation of N2O concentration. The H2O induced CH4 and N2O concentration errors were approximately linearly proportional to the residual H2O concentration. For the measurement of air flowing at 3 L per min, the residual H2O concentration was stabilized to approximately 14 ppmv, and the corresponding H2O induced errors were −1.3 ppbv for CH4 and 3.7 ppbv for N2O, respectively.

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27

Smyrl, N. R., D. M. Hembree, W. E. Davis, D. M. Williams y J. C. Vance. "Simultaneous GC-FT-IR/GC-MS Analysis for Isomer-Specific Identification and Quantitation of Complex Mixture Components". Applied Spectroscopy 46, n.º 2 (febrero de 1992): 277–82. http://dx.doi.org/10.1366/0003702924125636.

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The construction and capabilities of a new instrument combining infrared and mass spectrometry to simultaneously examine the effluent from a single capillary column gas chromatographic injection are described. Gas chromatography-mass spectrometry (GC-MS) is performed in the conventional manner. However, the Fourier transform infrared (FT-IR) portion of the instrument employs a new sampling method involving low-temperature trapping of the effluent from the gas chromatograph. The mass spectrometer was over two orders of magnitude more sensitive (161 fg detection limit for naphthalene) than the infrared (40 pg). The qualitative capabilities of infrared spectrometry, particularly when isomerspecific identifications are necessary, are shown to be highly complementary to the usual GC-MS method for analyzing complex mixtures

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28

Strug, Ivona, Christopher Utzat, Amedeo Cappione, Sara Gutierrez, Ryan Amara, Joseph Lento, Florian Capito, Romas Skudas, Elena Chernokalskaya y Timothy Nadler. "Development of a Univariate Membrane-Based Mid-Infrared Method for Protein Quantitation and Total Lipid Content Analysis of Biological Samples". Journal of Analytical Methods in Chemistry 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/657079.

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Biological samples present a range of complexities from homogeneous purified protein to multicomponent mixtures. Accurate qualification of such samples is paramount to downstream applications. We describe the development of an MIR spectroscopy-based analytical method offering simultaneous protein quantitation (0.25–5 mg/mL) and analysis of total lipid or detergent species, as well as the identification of other biomolecules present in biological samples. The method utilizes a hydrophilic PTFE membrane engineered for presentation of aqueous samples in a dried format compatible with fast infrared analysis. Unlike classical quantification techniques, the reported method is amino acid sequence independent and thus applicable to complex samples of unknown composition. By comparison to existing platforms, this MIR-based method enables direct quantification using minimal sample volume (2 µL); it is well-suited where repeat access and limited sample size are critical parameters. Further, accurate results can be derived without specialized training or knowledge of IR spectroscopy. Overall, the simplified application and analysis system provides a more cost-effective alternative to high-throughput IR systems for research laboratories with minimal throughput demands. In summary, the MIR-based system provides a viable alternative to current protein quantitation methods; it also uniquely offers simultaneous qualification of other components, notably lipids and detergents.

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29

Huffman, Scott W., Rohit Bhargava y Ira W. Levin. "Generalized Implementation of Rapid-Scan Fourier Transform Infrared Spectroscopic Imaging". Applied Spectroscopy 56, n.º 8 (agosto de 2002): 965–69. http://dx.doi.org/10.1366/000370202760249684.

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We describe a novel, generalized data acquisition sequence to allow rapid-scan Fourier transform infrared (FT-IR) spectroscopic imaging using focal plane array (FPA) detectors. This technique derives its applicability from the reproducible performance of modern FT-IR instrumentation and the availability of FPAs with simultaneous, full array acquisition, or snapshot electronics. Instead of sampling the entire interferogram in one mirror sweep over a predetermined retardation, as in traditional continuous-scanning techniques, the modulated light from the interferometer is recorded over several mirror sweeps. The FPA detector is synchronized for data acquisition after a specified delay with respect to the initiation of the mirror motion to provide a highly under-sampled interferogram. By incorporating appropriate delays in subsequent interferometer mirror scans, the entire interferogram is sampled and reconstructed. The signal-to-noise ratios (SNR) of the resulting interferograms are analyzed and are compared with step-scan spectroscopic imaging data.

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30

Zhu, Suyun, Mattia Scardamaglia, Jan Kundsen, Rami Sankari, Hamed Tarawneh, Robert Temperton, Louisa Pickworth et al. "HIPPIE: a new platform for ambient-pressure X-ray photoelectron spectroscopy at the MAX IV Laboratory". Journal of Synchrotron Radiation 28, n.º 2 (12 de febrero de 2021): 624–36. http://dx.doi.org/10.1107/s160057752100103x.

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HIPPIE is a soft X-ray beamline on the 3 GeV electron storage ring of the MAX IV Laboratory, equipped with a novel ambient-pressure X-ray photoelectron spectroscopy (APXPS) instrument. The endstation is dedicated to performing in situ and operando X-ray photoelectron spectroscopy experiments in the presence of a controlled gaseous atmosphere at pressures up to 30 mbar [1 mbar = 100 Pa] as well as under ultra-high-vacuum conditions. The photon energy range is 250 to 2200 eV in planar polarization and with photon fluxes >1012 photons s−1 (500 mA ring current) at a resolving power of greater than 10000 and up to a maximum of 32000. The endstation currently provides two sample environments: a catalysis cell and an electrochemical/liquid cell. The former allows APXPS measurements of solid samples in the presence of a gaseous atmosphere (with a mixture of up to eight gases and a vapour of a liquid) and simultaneous analysis of the inlet/outlet gas composition by online mass spectrometry. The latter is a more versatile setup primarily designed for APXPS at the solid–liquid (dip-and-pull setup) or liquid–gas (liquid microjet) interfaces under full electrochemical control, and it can also be used as an open port for ad hoc-designed non-standard APXPS experiments with different sample environments. The catalysis cell can be further equipped with an IR reflection–absorption spectrometer, allowing for simultaneous APXPS and IR spectroscopy of the samples. The endstation is set up to easily accommodate further sample environments.

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31

Consolino, Luigi, Malik Nafa, Michele De Regis, Francesco Cappelli, Saverio Bartalini, Akio Ito, Masahiro Hitaka et al. "Direct Observation of Terahertz Frequency Comb Generation in Difference-Frequency Quantum Cascade Lasers". Applied Sciences 11, n.º 4 (4 de febrero de 2021): 1416. http://dx.doi.org/10.3390/app11041416.

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Terahertz quantum cascade laser sources based on intra-cavity difference frequency generation from mid-IR devices are an important asset for applications in rotational molecular spectroscopy and sensing, being the only electrically pumped device able to operate in the 0.6–6 THz range without the need of bulky and expensive liquid helium cooling. Here we present comb operation obtained by intra-cavity mixing of a distributed feedback laser at λ = 6.5 μm and a Fabry–Pérot device at around λ = 6.9 μm. The resulting ultra-broadband THz emission extends from 1.8 to 3.3 THz, with a total output power of 8 μW at 78 K. The THz emission has been characterized by multi-heterodyne detection with a primary frequency standard referenced THz comb, obtained by optical rectification of near infrared pulses. The down-converted beatnotes, simultaneously acquired, confirm an equally spaced THz emission down to 1 MHz accuracy. In the future, this setup can be used for Fourier transform based evaluation of the phase relation among the emitted THz modes, paving the way to room-temperature, compact, and field-deployable metrological grade THz frequency combs.

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32

Smolikov, M. D., V. A. Shkurenok, L. I. Bikmetova, N. N. Leontieva y A. V. Lavrenov. "Simultaneous Isomerization of Hexane and Heptane in the Presence of Pt-Containing Tungstated Zirconia Catalysts". Kataliz v promyshlennosti 22, n.º 6 (28 de noviembre de 2022): 30–40. http://dx.doi.org/10.18412/1816-0387-2022-6-30-40.

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Isomerization of heptane and hexane and their mixtures in the presence of Pt/WO3-ZrO2 catalysts with the tungsten oxide content of 10–35 wt.% was studied. The best characteristics of isomerization of the С6–С7 alkanes mixture were observed on the catalysts with the WO3 content of 15–20 wt.%. According to ammonia thermodesorption data, the number of acid sites typically increases in this range of tungsten oxide content; according to IR spectroscopy of adsorbed CO, this occurs mostly with an increase in the number of Broensted acid sites.

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33

Krstić, Marko y Slavica Ražić. "Analytical Approaches to the Characterization of Solid Drug Delivery Systems with Porous Adsorbent Carriers". Current Medicinal Chemistry 25, n.º 33 (24 de octubre de 2018): 3956–72. http://dx.doi.org/10.2174/0929867325666180212120908.

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A large variety of analytical techniques are available to meet the needs of characterization of solid samples. But, when solid drug delivery systems are concerned we are faced with demanding methodologies which have to compile capabilities of analytical techniques in regard to large diversity of structures and surface functionality of analyzed adsorbent carriers. In this review, the most commonly used analytical techniques are presented with their basic principles, advantages and disadvantages in applications of interest. Adsorbent carriers are widely used today as ingredients in the formulation of pharmaceutical forms, for increasing the dissolution rate of the drug and hence the bioavailability. They are also used in the formulation of substances with modified or target drug release into a specific tissue. Methods of thermal analysis (Thermogravimetry - TGA, Differential Scanning Calorimetry - DSC and Thermal microscopy - TM), spectroscopic methods (Infrared Spectroscopy - IR, especially Fourier Transform Infrared Spectroscopy - FTIR and Raman spectroscopy), crystallographic methods (Powder X-Ray Diffraction - PXRD) and finally Scanning Electron Microscopy (SEM) are the most powerful in the characterization of modern therapeutic systems with porous adsorbents. The problem-solving power of each particular analytical method is often enhanced by using simultaneous methods rather than a single technique.

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34

Daescu, M., M. Oprica, I. Smaranda, E. Matei, D. Nastac, O. Cramariuc, B. Cramariuc y M. Baibarac. "Vibrational and Photoluminescence Properties of Composites Based on Double-Walled Carbon Nanotubes, Poly(o-phenylenediamine) and Poly(ethylene oxide)". Journal of Nanoscience and Nanotechnology 21, n.º 4 (1 de abril de 2021): 2334–41. http://dx.doi.org/10.1166/jnn.2021.18975.

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Chemical polymerization of o-phenylenediamine (OPD) in the presence of poly(ethylene oxide), double-wall carbon nanotubes (DWNTs) and ferric chloride is carried out in order to obtain composites based on the poly(o-phenylenediamine)-poly(ethylene oxide) (POPD-PEO) fibres covered and interconnected with DWNTs. Vibrational and photoluminescence properties of these composite materials as well as their morphologies are shown by infrared (IR) spectroscopy, Raman scattering, photoluminescence (PL) and scanning electron microscopy (SEM). An adsorption of DWNTs onto the POPD rods surface in the absence and in the presence of PEO is highlighted by SEM. The vibrational changes reported by Raman scattering and IR spectroscopy prove a covalent functionalization of DWNTs with the macromolecular compound POPD which is doped with FeCl−4 ions. New hydrogen bonds are generated between POPD covalently functionalized DWNTs and hydroxyl groups of PEO according to IR spectroscopic studies. The two macromolecular compounds, POPD and POPD-PEO, show a complex emission band with maxima at 572 and 566 nm, having a shoulder at 667 nm. A significant change in the profile of the PL bands of POPD and POPD-PEO is induced in the DWNTs presence. We show that DWNTs induce (i) a diminution in the POPD PL band intensity peaked between 525–600 nm simultaneous with the increase in the intensity of the PL band situated in the 600–800 nm spectral range and (ii) an enhancement process of the emission band localized in the 475–800 nm spectral range in the case of POPD-PEO.

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35

Chung, Hoeil, Mark A. Arnold, Martin Rhiel y David W. Murhammer. "Simultaneous Measurements of Glucose, Glutamine, Ammonia, Lactate, and Glutamate in Aqueous Solutions by Near-Infrared Spectroscopy". Applied Spectroscopy 50, n.º 2 (febrero de 1996): 270–76. http://dx.doi.org/10.1366/0003702963906447.

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Calibration models are generated and evaluated for the measurement of five different components in synthetic mixtures prepared in aqueous solutions. Mixtures of glucose, glutamine, ammonia, lactate, and glutamate were prepared to simulate concentration levels expected during routine bioreactor fermentation processes. Near-IR spectra were collected from these solutions over the spectral range from 5000 to 4000 cm−1. This spectral information was used to build individual multivariate calibration models for each analyte. Models were constructed on the basis of partial least-squares regression of raw and Fourier filtered absorbance spectra. Each analyte could be detected selectively with mean percent errors of prediction ranging from 4 to 8%.

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36

Guo, Zhi Rui, Y. DuanMu y Ning Gu. "One-Step Preparation of Fibrous Aggregates of Gold Nanoparticles Using Aniline as Reducing Agent as well as Monomer". Solid State Phenomena 121-123 (marzo de 2007): 251–54. http://dx.doi.org/10.4028/www.scientific.net/ssp.121-123.251.

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Nanoscaled fibrous aggregates of gold nanoparticles have been synthesized by a simultaneous reduction-oxidation polymerization process using aniline as reducing agent as well as monomer in an ethanol medium. Time-dependent UV-Vis absorption spectroscopy was used to track the formation process of gold nanoparticles. The transmission electron microscopy (TEM) images and Fourier transform infrared (FT-IR) spectrum of the as-preapred products indicate these gold nanoparticles were binded by the oxidation polymerization resultant of aniline.

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37

Ogurtsov, Vladimir A. y Oleg A. Rakitin. "(2,3-Dihydro-1H-indol-5-ylmethyl)amine". Molbank 2021, n.º 3 (5 de julio de 2021): M1248. http://dx.doi.org/10.3390/m1248.

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New (2,3-dihydro-1H-indol-5-ylmethyl)amine was synthesized from 2-((1-acetylindolin-5-yl)methyl)isoindoline-1,3-dione by simultaneous deprotection of phthalimide and acetyl groups. The structure of the newly synthesized compounds was established by elemental analysis, high resolution mass-spectrometry, 1H, 13C NMR and IR spectroscopy and mass-spectrometry. The resulting compound is a convenient intermediate for various disubstituted 1-(indolin-5-yl)methanamines, which may be of interest as substances with useful pharmacological properties.

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38

Schubert, M. M., T. P. Häring, G. Bräth, H. A. Gasteiger y R. J. Behm. "New DRIFTS Cell Design for the Simultaneous Acquisition of IR Spectra and Kinetic Data Using On-Line Product Analysis". Applied Spectroscopy 55, n.º 11 (noviembre de 2001): 1537–43. http://dx.doi.org/10.1366/0003702011953775.

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A new design for a DRIFTS (diffuse reflectance infrared Fourier transform spectrometry) cell for in situ studies in heterogeneous catalysis is presented, which allows for improved reaction control (i.e., gas flow, temperature, minimized background conversion) and for precise kinetic measurements via on-line gas analysis by a tandem-arranged gas chromatograph. Specifically, the very low background activity of the cell itself for CO and H2 oxidation makes it possible to study the preferential CO oxidation in H2-rich gases (PROX) at relevant reaction temperatures (150–350 °C) and reactant concentrations (≤1 kPa CO and O2). Comparison with results obtained in a quartz tube reactor shows excellent agreement with the reaction rates obtained in the DRIFTS cell. The improved performance of the new DRIFTS cell design is demonstrated by examining the influence of CO2 on the PROX reaction over a Au/Fe2O3 catalyst. The addition of CO2 to idealized reformate (varying CO and O2 partial pressures, 75 kPa H2, balance N2) significantly reduces both the CO oxidation rate and the selectivity of the PROX reaction on Au/α-Fe2O3 and strongly affects the frequency of the C–O stretch vibration of adsorbed CO due to CO2 coadsorption.

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39

Johansen, Ib-Rune, Glenn Terje Lines, Atle Honne y Tonje Midtgaard. "Calibration of an FT-IR Spectrometer for Ambient Air Monitoring Using PLS". Applied Spectroscopy 51, n.º 10 (octubre de 1997): 1540–46. http://dx.doi.org/10.1366/0003702971939073.

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The objective of this work has been to develop a robust calibration method for simultaneous multigas detection with a Fourier transform infrared (FT-IR) system. Calibration models for the identification and quantification of 23 gases in the presence of high concentrations of background gases such as water vapor, carbon dioxide, and methane have been obtained for an FT-IR instrument with 0.7-cm−1 resolution. The calibration models have been tested on a breadboard instrument for trace gas measurement in manned space missions. The results show that FT-IR combined with multivariate methods such as partial least-squares (PLS) and proper pretreatment of the infrared spectra used in calibration is well suited for this purpose. A procedure for baseline drift compensation has been introduced to make the system insensitive to baseline drift and variations in transmittance. This baseline drift compensation also reduces the need for background measurements. Further, a procedure for incorporating a priori information about the instrument signal-to-noise ratio (SNR) and the absorption strength of interfering absorption lines has been developed. Indoor air monitoring and industrial process monitoring are other possible application areas for these techniques. Parts of this work have been performed in a project for the European Space Agency (ESA) in cooperation with Kayser-Threde GmbH and Daimler-Benz Aerospace, Dornier GmbH.

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40

Herklotz, Frank, Tom Rubin, Malte Sinnreich, Alexander Helmke, Theodore von Haimberger y Karsten Heyne. "Fast Simultaneous CO2 Gas Temperature and Concentration Measurements by Quantum Cascade Laser Absorption Spectroscopy". Applied Sciences 12, n.º 10 (17 de mayo de 2022): 5057. http://dx.doi.org/10.3390/app12105057.

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A quantum cascade laser-based sensing technique is presented which allows for in situ high-precision temperature and/or CO2 concentration measurements of gases in the room temperature regime with sampling rates up to about 40 kHz. The method is based on Boltzmann-like thermally populated fundamental and hot-band rovibrational transitions of CO2 with opposite temperature dependence. Single absorption spectra at about 2350 to 2352 cm−1 are recorded by a nanosecond frequency down chirped IR pulse of a pulsed distributed feedback quantum cascade laser (intrapulse mode). The statistical uncertainty (1σ) in the temperature measurement within one laser pulse is about 1 K and can be further reduced down to about 0.1 K by time averaging over 100 ms. Online temperature and CO2 concentration measurements on a breath simulator controlled gas flow were performed to demonstrate response-time and sensitivity for an application-driven test system.

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41

Tommola, Jorma, Matti Laine, Marianna Sunnari y Juha O. Rinne. "Images of shadowing and interpreting". Interpreting. International Journal of Research and Practice in Interpreting 5, n.º 2 (31 de diciembre de 2000): 147–67. http://dx.doi.org/10.1075/intp.5.2.06tom.

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We begin by noting that, in addition to the more or less established trends of cognitive modelling and neurolinguistic or behavioural experimentation, a more recent orientation in research on interpreting (IR) as a complex cognitive process is functional neuroimaging. We then describe current brain imaging methods — electroencephalography, magnetoencephalography, positron emission tomography, functional magnetic resonance imaging, and near-infrared spectroscopy — and provide selected examples of their use in language processing and interpreting research, accompanied with brief evaluations of their applicability for IR. In spite of limitations related to invasiveness, temporal resolution, and experimental design, positron emission tomography (PET) is potentially the strongest tool for investigations of the neural substrates of ongoing interpreting performance. Finally, we describe what we believe is the first published study of speech shadowing and professional simultaneous interpreting using PET. Shadowing of the non-dominant language produces more extensive activations in the temporal cortex and motor regions than shadowing of the dominant language, which suggests that even in the simultaneous repetition task, the less automatized language recruits more neural resources. Simultaneous interpreting, whether into the dominant or into the non-dominant language, predominantly activates left-hemispheric structures. Activation patterns are, however, clearly modulated by the direction of interpreting, with more extensive activation during interpreting into the non-dominant language.

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42

Smirnov, Mikhail S., Aleksey S. Perepelitsa, Tamara S. Kondratenko, Andrey I. Zvyagin y Oleg V. Ovchinnikov. "Spectral properties of hybrid associates of colloidal quantum dots Zn0.5Cd0.5S, europium tenoyltrifluoroacetonate and methylene blue". EPJ Web of Conferences 190 (2018): 04017. http://dx.doi.org/10.1051/epjconf/201819004017.

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Hybrid associates formed from colloidal Zn0.5Cd0.5S quantum dots, passivated with thioglycolic acid, europium tenoyltrioteracetonate and methylene blue molecules, absorption, luminescence, IR and time-resolved spectroscopy technique are studied. The shift of the IR absorption bands of COO- and C=O groups of thioglycolic acid and europium thenoyltrifluoroacetonate has been detected. An increase in the efficiency of excitation of europium luminescence and a simultaneous increase lifetime of its luminescence upon adsorption on Zn0.5Cd0.5S quantum dots were found. Addition of methylene blue (thionine) molecules leads to quenching of the trap state luminescence of Zn0.5Cd0.5S and intracentric luminescence of Eu3+. A conclusion about the adsorption of Eu3+ on the surface of Zn0.5Cd0.5S quantum dots and the nonradiative energy transfer to methylene blue molecules was made.

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43

Pollard, Benjamin y Markus B. Raschke. "Correlative infrared nanospectroscopic and nanomechanical imaging of block copolymer microdomains". Beilstein Journal of Nanotechnology 7 (22 de abril de 2016): 605–12. http://dx.doi.org/10.3762/bjnano.7.53.

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Intermolecular interactions and nanoscale phase separation govern the properties of many molecular soft-matter systems. Here, we combine infrared vibrational scattering scanning near-field optical microscopy (IR s-SNOM) with force–distance spectroscopy for simultaneous characterization of both nanoscale optical and nanomechanical molecular properties through hybrid imaging. The resulting multichannel images and correlative analysis of chemical composition, spectral IR line shape, modulus, adhesion, deformation, and dissipation acquired for a thin film of a nanophase separated block copolymer (PS-b-PMMA) reveal complex structural variations, in particular at domain interfaces, not resolved in any individual signal channel alone. These variations suggest that regions of multicomponent chemical composition, such as the interfacial mixing regions between microdomains, are correlated with high spatial heterogeneity in nanoscale material properties.

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44

Kuang, Yiwen, Mengxue Li, Shiyu Hu, Lu Yang, Zhanning Liang, Jiaqi Wang, Hongmei Jiang, Xiaoyun Zhou y Zhaohong Su. "One-Step Co-Electrodeposition of Copper Nanoparticles-Chitosan Film-Carbon Nanoparticles-Multiwalled Carbon Nanotubes Composite for Electroanalysis of Indole-3-Acetic Acid and Salicylic Acid". Sensors 22, n.º 12 (13 de junio de 2022): 4476. http://dx.doi.org/10.3390/s22124476.

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A sensitive simultaneous electroanalysis of phytohormones indole-3-acetic acid (IAA) and salicylic acid (SA) based on a novel copper nanoparticles-chitosan film-carbon nanoparticles-multiwalled carbon nanotubes (CuNPs-CSF-CNPs-MWCNTs) composite was reported. CNPs were prepared by hydrothermal reaction of chitosan. Then the CuNPs-CSF-CNPs-MWCNTs composite was facilely prepared by one-step co-electrodeposition of CuNPs and CNPs fixed chitosan residues on modified electrode. Scanning electron microscope (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and linear sweep voltammetry (LSV) were used to characterize the properties of the composite. Under optimal conditions, the composite modified electrode had a good linear relationship with IAA in the range of 0.01–50 μM, and a good linear relationship with SA in the range of 4–30 μM. The detection limits were 0.0086 μM and 0.7 μM (S/N = 3), respectively. In addition, the sensor could also be used for the simultaneous detection of IAA and SA in real leaf samples with satisfactory recovery.

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45

Aykas, Didem Peren, Karla Rodrigues Borba y Luis E. Rodriguez-Saona. "Non-Destructive Quality Assessment of Tomato Paste by Using Portable Mid-Infrared Spectroscopy and Multivariate Analysis". Foods 9, n.º 9 (15 de septiembre de 2020): 1300. http://dx.doi.org/10.3390/foods9091300.

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This research aims to provide simultaneous predictions of tomato paste’s multiple quality traits without any sample preparation by using a field-deployable portable infrared spectrometer. A total of 1843 tomato paste samples were supplied by four different leading tomato processors in California, USA, over the tomato seasons of 2015, 2016, 2017, and 2019. The reference levels of quality traits including, natural tomato soluble solids (NTSS), pH, Bostwick consistency, titratable acidity (TA), serum viscosity, lycopene, glucose, fructose, ascorbic acid, and citric acid were determined by official methods. A portable FT-IR spectrometer with a triple-reflection diamond ATR sampling system was used to directly collect mid-infrared spectra. The calibration and external validation models were developed by using partial least square regression (PLSR). The evaluation of models was conducted on a randomly selected external validation set. A high correlation (RCV = 0.85–0.99) between the reference values and FT-IR predicted values was observed from PLSR models. The standard errors of prediction were low (SEP = 0.04–35.11), and good predictive performances (RPD = 1.8–7.3) were achieved. Proposed FT-IR technology can be ideal for routine in-plant assessment of the tomato paste quality that would provide the tomato processors with accurate results in shorter time and lower cost.

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Weng, Wubin, Marcus Aldén y Zhongshan Li. "Simultaneous Quantitative Detection of HCN and C2H2 in Combustion Environment Using TDLAS". Processes 9, n.º 11 (14 de noviembre de 2021): 2033. http://dx.doi.org/10.3390/pr9112033.

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Emission of nitrogen oxides (NOx) and soot particles during the combustion of biomass fuels and municipal solid waste is a major environmental issue. Hydrogen cyanide (HCN) and acetylene (C2H2) are important precursors of NOx and soot particles, respectively. In the current work, infrared tunable diode laser absorption spectroscopy (IR-TDLAS), as a non-intrusive in situ technique, was applied to quantitatively measure HCN and C2H2 in a combustion environment. The P(11e) line of the first overtone vibrational band v1 of HCN at 6484.78 cm−1 and the P(27e) line of the v1 + v3 combination band of C2H2 at 6484.03 cm−1 were selected. However, the infrared absorption of the ubiquitous water vapor in the combustion environment brings great uncertainty to the measurement. To obtain accurate temperature-dependent water spectra between 6483.8 and 6485.8 cm−1, a homogenous hot gas environment with controllable temperatures varying from 1100 to 1950 K provided by a laminar flame was employed to perform systematic IR-TDLAS measurements. By fitting the obtained water spectra, water interference to the HCN and C2H2 measurement was sufficiently mitigated and the concentrations of HCN and C2H2 were obtained. The technique was applied to simultaneously measure the temporally resolved release of HCN and C2H2 over burning nylon 66 strips in a hot oxidizing environment of 1790 K.

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Liu, Yang, Song Wang, Yong Liang, Huan Zhou, Xinshu Li, Lin Duan, Shuang Chen, Sanxi Li, Linnan Zhang y Ailing Zhang. "Simultaneous removal of methyl orange and Cr(VI) using polyethyleneimine-modified corncob-derived carbon material". BioResources 15, n.º 4 (5 de agosto de 2020): 7342–56. http://dx.doi.org/10.15376/biores.15.4.7342-7356.

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Polyethyleneimine (PEI) modified corncob-derived carbon material (CCM) was prepared by the simple wet-impregnation technique. Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), and nitrogen isothermal adsorption/desorption measurements were used to compare the structural differences between the CCM and the PEI-modified CCM (PEI-CCM). In the single-pollutant removal experiment, the PEI-CCM showed high adsorption capacities for methyl orange (MO) and Cr(VI). However, the CCM only showed high adsorption capacity for MO. Moreover, the PEI-CCM exhibited high removal efficiencies in the simultaneous removal of MO and Cr(VI), with final removal efficiencies of 100% and 95%, respectively. The reusability experiment of PEI-CCM indicated that, after four recycles, PEI-CCM maintained high performance with the removal efficiency of MO and Cr(VI) decreased less than 3% and 16%, respectively. The prepared PEI-CCM could be a high-performance adsorbent for the simultaneous removal of MO and Cr(VI) from water containing multiple pollutants.

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48

Morzinski, Katie M., Laird M. Close, Jared R. Males, Phil M. Hinz, Alfio Puglisi, Simone Esposito, Armando Riccardi et al. "Direct imaging of Beta Pictoris b with first-light Magellan Adaptive Optics". Proceedings of the International Astronomical Union 8, S299 (junio de 2013): 252–56. http://dx.doi.org/10.1017/s1743921313008508.

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AbstractMagAO is the newly-commissioned adaptive optics (AO) instrument on the Magellan Clay telescope at Las Companas Observatory, Chile. MagAO has two co-mounted science cameras: VisAO for visible-light direct and spectral-differential imaging; and Clio for near to thermal IR direct imaging, non-redundant-mask interference, and prism spectroscopy. We demonstrate MagAO's simultaneous visible and infrared AO performance via direct images of exoplanet Beta Pictoris b. The planet was detected in 5 passbands from 0.9–5μm. Here we show the infrared images; the visible observations are presented in Males et al. 2013. MagAO is the first AO system to offer good performance with extensive coverage across the O/IR spectrum and thus offers an unprecedented opportunity to study the spectral energy distributions of directly-imaged extrasolar planetary atmospheres.

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49

Göbel, R., R. Krska, R. Kellner, R. W. Seitz y S. A. Tomellini. "Investigation of Different Polymers as Coating Materials for IR/ATR Spectroscopic Trace Analysis of Chlorinated Hydrocarbons in Water". Applied Spectroscopy 48, n.º 6 (junio de 1994): 678–83. http://dx.doi.org/10.1366/000370294774369054.

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Polymer-coated attenuated total reflection (ATR) elements have been used to compare the diffusion behavior and enrichment from aqueous solutions of three different chlorinated hydrocarbons (CHCs) — monochlorobenzene (MCB), chloroform (CF), and tetrachloroethylene (TeCE)—into different polymers. The influence of polymer properties such as glass transition temperature and crystallinity and the effect of the polymer background IR absorption and varying thicknesses of the polymer membranes to the detectability were investigated. The crystallinity and the glass transition temperature have a very pronounced influence on the velocity of the diffusion process, whereas the partition coefficient influences the amount of CHC diffusing into the polymer membrane. The time constants for 90% saturation of the polymer with the test analytes are in the range of 8 to 40 min, depending on the nature of the polymer and analyte. A linear calibration graph was obtained for simultaneous detection of all three test analytes in the range from 5 mg/L to 100 mg/L CHC with detection limits of 1.5 to 2 mg/L. Coefficients for CHC partitioning between water and polymers measured by ATR/IR were in good agreement with values determined by GC/MS.

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50

He, Qian, Xianxian Wang, Huijun He y Jing Zhang. "Simultaneous determination of noble metals (Rh, Pd, Ir, Pt, and Au) in environmental samples by nebulized film dielectric barrier discharge vapor generation coupled with inductively coupled plasma mass spectrometry". Journal of Analytical Atomic Spectrometry 35, n.º 11 (2020): 2704–11. http://dx.doi.org/10.1039/d0ja00343c.

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This work provides a sensitive analytical approach for the determination of Rh, Pd, Ir, Pt, and Au by nebulized film dielectric barrier discharge (NFDBD) vapor generation sampling coupled with ICP-MS.

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