TY - JOUR
T1 - Sulfur isotope ratio measurements of individual sulfate particles by NanoSIMS
AU - Winterholler, Baerbel
AU - Hoppe, Peter
AU - Foley, Stephen
AU - Andreae, Meinrat O.
PY - 2008/4/15
Y1 - 2008/4/15
N2 - The sulfur isotopic compositions of barite (BaSO4), anhydrite (CaSO4), gypsum (CaSO4·2H2O), mascagnite ((NH4)2SO4), thenardite (Na2SO4), boetite (K2SO4), epsomite (MgSO4·7H2O), magnesium sulfate (MgSO4·xH2O) and cysteine (an amino acid) were determined with a Cameca NanoSIMS 50 ion microprobe employing a Cs+ primary ion beam and measuring negative secondary ions. This ion microprobe permits the analysis of sulfur isotope ratios in sulfates on 0.001-0.5 ng of sample material, enabling the analysis of individual S-bearing particles with diameters as small as 500 nm. The grain-to-grain reproducibility of measurements is typically 5‰ (1σ) for micron-sized grains, <5‰ for submicron-sized grains down to roughly 500 nm, and <2‰ for polished thin sections and ultra microtome sections which were studied for comparison. The role of chemical composition (matrix effect) and sample preparation technique on the instrumental mass fractionation (IMF) of the 34S/32S ratio in the NanoSIMS has been investigated for different sulfates and one amino acid. The IMF varies by ∼15‰ between the standards studied here, underlining the importance of a good understanding of the matrix-specific IMF correction in order to get precise S isotope data for very small samples such as aerosol particles. A good correlation between IMF and ionic radius of the cations in sulfates was found, permitting inference of IMF corrections for sulfates for which no isotope standards are available.
AB - The sulfur isotopic compositions of barite (BaSO4), anhydrite (CaSO4), gypsum (CaSO4·2H2O), mascagnite ((NH4)2SO4), thenardite (Na2SO4), boetite (K2SO4), epsomite (MgSO4·7H2O), magnesium sulfate (MgSO4·xH2O) and cysteine (an amino acid) were determined with a Cameca NanoSIMS 50 ion microprobe employing a Cs+ primary ion beam and measuring negative secondary ions. This ion microprobe permits the analysis of sulfur isotope ratios in sulfates on 0.001-0.5 ng of sample material, enabling the analysis of individual S-bearing particles with diameters as small as 500 nm. The grain-to-grain reproducibility of measurements is typically 5‰ (1σ) for micron-sized grains, <5‰ for submicron-sized grains down to roughly 500 nm, and <2‰ for polished thin sections and ultra microtome sections which were studied for comparison. The role of chemical composition (matrix effect) and sample preparation technique on the instrumental mass fractionation (IMF) of the 34S/32S ratio in the NanoSIMS has been investigated for different sulfates and one amino acid. The IMF varies by ∼15‰ between the standards studied here, underlining the importance of a good understanding of the matrix-specific IMF correction in order to get precise S isotope data for very small samples such as aerosol particles. A good correlation between IMF and ionic radius of the cations in sulfates was found, permitting inference of IMF corrections for sulfates for which no isotope standards are available.
UR - http://www.scopus.com/inward/record.url?scp=40649108500&partnerID=8YFLogxK
U2 - 10.1016/j.ijms.2008.01.003
DO - 10.1016/j.ijms.2008.01.003
M3 - Article
AN - SCOPUS:40649108500
SN - 1387-3806
VL - 272
SP - 63
EP - 77
JO - International Journal of Mass Spectrometry
JF - International Journal of Mass Spectrometry
IS - 1
ER -