Selected papers from the latest issue:
Solid sampling in analysis of animal organs by two-jet plasma atomic emission spectrometry
30 November 2011, 01:59:44
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 November 2011
Natalia P. Zaksas, Georgy A. Nevinsky
A study of high-power two-jet plasma capabilities for the direct multi-elemental analysis of animal organs was undertaken. The experimental conditions chosen allow the direct analysis of different animal organs after drying and grinding to powder (particle size 20–200 μm). It was found that evaporation efficiency of the samples depends on the particle size and thermal stability of tissues and can be improved by reduction of a carrier gas flow. Calibration samples based on graphite powder and a tenfold dilution of powdered samples with buffer (graphite powder containing 15% NaCl) were used. 5–10 mg of the sample was quite enough to get the detection limits of elements at the level of 0.1-10 μg g. A prior carbonization procedure (not ashing) makes it possible to decrease the detection limits of elements by an order of magnitude. The validation of the techniques was confirmed by the analysis of certified reference materials NIST 8414, BCR 278R and NCS ZC 81001 as well as by using different sample preparation procedures.
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 November 2011
Natalia P. Zaksas, Georgy A. Nevinsky
A study of high-power two-jet plasma capabilities for the direct multi-elemental analysis of animal organs was undertaken. The experimental conditions chosen allow the direct analysis of different animal organs after drying and grinding to powder (particle size 20–200 μm). It was found that evaporation efficiency of the samples depends on the particle size and thermal stability of tissues and can be improved by reduction of a carrier gas flow. Calibration samples based on graphite powder and a tenfold dilution of powdered samples with buffer (graphite powder containing 15% NaCl) were used. 5–10 mg of the sample was quite enough to get the detection limits of elements at the level of 0.1-10 μg g. A prior carbonization procedure (not ashing) makes it possible to decrease the detection limits of elements by an order of magnitude. The validation of the techniques was confirmed by the analysis of certified reference materials NIST 8414, BCR 278R and NCS ZC 81001 as well as by using different sample preparation procedures.
Highlights
► A two-jet plasma was used for direct analysis of powdered animal organs. ► The analysis of powders with particles 20–200 μm in size was possible. ► Calibration samples based on graphite powder were used. ► Carbonization of the sample allows decreasing detection limits of elements.Laser Induced Breakdown Spectroscopy Library for the Martian Environment
28 October 2011, 20:46:38
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 October 2011
A. Cousin, O. Forni, S. Maurice, O. Gasnault, C. Fabre, ...
The NASA Mars Science Laboratory rover will carry the first Laser Induced Breakdown Spectroscopy experiment in spa ChemCam. We have developed a laboratory model which mimics ChemCam's main characteristics. We used a set of target samples relevant to Mars geochemistry, and we recorded individual spectra. We propose a data reduction scheme for Laser Induced Breakdown Spectroscopy data incorporating de-noising, continuum removal, and peak fitting. Known effects of the Martian atmosphere are confirmed with our experiment: better Signal-to-Noise Ratio on Mars compared to Earth, narrower peak width, and essentially no self-absorption. The wavelength shift of emission lines from air to Mars pressure is discussed. The National Institute of Standards and Technology vacuum database is used for wavelength calibration and to identify the elemental lines. Our Martian database contains 1336 lines for 32 elements: H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ar, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Rb, Sr, Cs, Ba, and Pb. It is a subset of the National Institute of Standards and Technology database to be used for Martian geochemistry. Finally, synthetic spectra can be built from the Martian database. Correlation calculations help to distinguish between elements in case of uncertainty. This work is used to create tools and support data for the interpretation of ChemCam results.
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 October 2011
A. Cousin, O. Forni, S. Maurice, O. Gasnault, C. Fabre, ...
The NASA Mars Science Laboratory rover will carry the first Laser Induced Breakdown Spectroscopy experiment in spa ChemCam. We have developed a laboratory model which mimics ChemCam's main characteristics. We used a set of target samples relevant to Mars geochemistry, and we recorded individual spectra. We propose a data reduction scheme for Laser Induced Breakdown Spectroscopy data incorporating de-noising, continuum removal, and peak fitting. Known effects of the Martian atmosphere are confirmed with our experiment: better Signal-to-Noise Ratio on Mars compared to Earth, narrower peak width, and essentially no self-absorption. The wavelength shift of emission lines from air to Mars pressure is discussed. The National Institute of Standards and Technology vacuum database is used for wavelength calibration and to identify the elemental lines. Our Martian database contains 1336 lines for 32 elements: H, Li, Be, B, C, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ar, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Rb, Sr, Cs, Ba, and Pb. It is a subset of the National Institute of Standards and Technology database to be used for Martian geochemistry. Finally, synthetic spectra can be built from the Martian database. Correlation calculations help to distinguish between elements in case of uncertainty. This work is used to create tools and support data for the interpretation of ChemCam results.
Highlights
► Chemcam: First Laser Induced Breakdown Spectroscopy technique on Mars. ► Creation of a LIBS specific database to ChemCam on Mars. ► Data reduction scheme is proposed. ► Best signal under Martian conditions. ► LIBS emission lines database: subset of NIST database for Martian geochemistry.Flow injection-chemical vapor generation atomicfluorescence spectrometry hyphenated system for organic mercury determination: A step forward
28 October 2011, 20:46:38
Publication year: 2011
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 October 2011
Valeria Angeli, Simona Biagi, Silvia Ghimenti, Massimo Onor, Alessandro D'Ulivo, ...
Monomethylmercury and ethyl mercury were determined on line using flow injection-chemical vapour generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethyl mercury were detected by atomic fluorescence spectrometry in a Ar/H2miniaturized flame after sodium borohydride reduction to Hg, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H2microflame was investigated.The behavior of inorganic mercury, monomethylmercury and ethyl mercury and their cysteine-complexes was also studied by continuous flow - chemical vapour generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethyl mercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethyl mercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10 mol L), thus allowing the organic/inorganic mercury speciation.The detection limits of the flow injection- chemical vapour generation atomic fluorescence spectrometry method were about 45 nmol L(as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 μmol Lwere obtained. Recoveries of monomethylmercury and ethyl mercury with respect to inorganic mercury were never less than 91%. Flow injection- chemical vapour generation atomic fluorescence spectrometry method was validated by analyzing the TORT-1 certificate reference material, which contains only monomethylmercury, and obtaining 83 ± 5% of monomethylmercury recovered, respectively. This method was also applied to the determination of monomethylmercury in saliva samples.
Source: Spectrochimica Acta Part B: Atomic Spectroscopy, Available online 28 October 2011
Valeria Angeli, Simona Biagi, Silvia Ghimenti, Massimo Onor, Alessandro D'Ulivo, ...
Monomethylmercury and ethyl mercury were determined on line using flow injection-chemical vapour generation atomic fluorescence spectrometry without neither requiring a pre-treatment with chemical oxidants, nor UV/MW additional post column interface, nor organic solvents, nor complexing agents, such as cysteine. Inorganic mercury, monomethylmercury and ethyl mercury were detected by atomic fluorescence spectrometry in a Ar/H2miniaturized flame after sodium borohydride reduction to Hg, monomethylmercury hydride and ethylmercury hydride, respectively. The effect of mercury complexing agent such as cysteine, ethylendiaminotetracetic acid and HCl with respect to water and Ar/H2microflame was investigated.The behavior of inorganic mercury, monomethylmercury and ethyl mercury and their cysteine-complexes was also studied by continuous flow - chemical vapour generation atomic fluorescence spectrometry in order to characterize the reduction reaction with tetrahydroborate. When complexed with cysteine, inorganic mercury, monomethylmercury and ethyl mercury cannot be separately quantified varying tetrahydroborate concentration due to a lack of selectivity, and their speciation requires a pre-separation stage (e.g. a chromatographic separation). If not complexed with cysteine, monomethylmercury and ethyl mercury cannot be separated, as well, but their sum can be quantified separately with respect to inorganic mercury choosing a suitable concentration of tetrahydroborate (e.g. 10 mol L), thus allowing the organic/inorganic mercury speciation.The detection limits of the flow injection- chemical vapour generation atomic fluorescence spectrometry method were about 45 nmol L(as mercury) for all the species considered, a relative standard deviation ranging between 1.8 and 2.9% and a linear dynamic range between 0.1 and 5 μmol Lwere obtained. Recoveries of monomethylmercury and ethyl mercury with respect to inorganic mercury were never less than 91%. Flow injection- chemical vapour generation atomic fluorescence spectrometry method was validated by analyzing the TORT-1 certificate reference material, which contains only monomethylmercury, and obtaining 83 ± 5% of monomethylmercury recovered, respectively. This method was also applied to the determination of monomethylmercury in saliva samples.
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