The unprecedented use of high-resolution continuum source molecular absorption spectrometry (HR-CS MAS) for the fractionation of organic and inorganic sulfur (S) species through monitoring the CS molecule is presented here. Two separate methods for determining organic (CS) and inorganic (CS) sulfur were developed to work sequentially. The optimized temperature program for both methodologies has two pyrolysis steps and one vaporization step (1st T: 1800 and 2T: 800 °C, and T: 2500 °C).
View Article and Find Full Text PDFIn this study, we report the simultaneous determination of bromine and fluorine using Second-Order Calibration High-Resolution Continuum Source Graphite Furnace Molecular Absorption Spectrometry (HR CS MAS). The instrumental data acquired correspond to the time versus wavelength matrix per sample that were analyzed using Parallel Factor Analysis (PARAFAC), along with Unfold and N-way Partial Least Squares combined with a post-calibration step known as Residual Bilinearization (U and N PLS/RBL). Despite the significant difference in sensitivity between bromine and fluorine, all approaches provided reasonably accurate results when predicting both analytes in synthetic mixtures within a controlled environment.
View Article and Find Full Text PDFFor the very first time, a microemulsion system in the Winsor II (WII) equilibrium was applied in a sample preparation method for extraction and pre-concentration in the determination of Pb, Cd, Co, Tl, Cu and Ni, in natural waters by high resolution continuum source atomic absorption spectrometry (HR-CS AAS). The method was optimized using the graphite furnace atomization. A simplex-centroid design for determine optimum extraction condition (77.
View Article and Find Full Text PDFParticulate matter (PM) impregnated with methlymercury (MeHg) was analyzed using atomic absorption spectrometry coupled to a customized dielectric barrier discharge (DBD) device. Chemical vapor generation (CVG) was applied to generate methylmercury hydride and the DBD device promoted bond cleavage with subsequent release of free Hg atoms to the gas phase. Hydride generation was carried out using a lab-made syringe-based device in batch mode using argon as a carrier gas.
View Article and Find Full Text PDFThis work describes the application of an experimental design in optimizing the decomposition and spectrometer operational conditions for analysis of fish feeds. The content of 22 elements (six macroelements, four microelements and eleven trace elements) in feeds for fishes (ornamental and for human consumption) was determined by inductively coupled plasma (ICP)-based methods. Limits of quantification were obtained and the values ranged between 0.
View Article and Find Full Text PDFMethod development for the pre-concentration of mercury in human hair, dogfish liver and dogfish muscle samples using cloud-point extraction and cold vapor atomic absorption spectrometry is demonstrated. Before the extraction, the samples were submitted to microwave-assisted digestion in a mixture of H(2)O(2) and HNO(3). Cloud point extraction was carried out using 0.
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