TY - JOUR
T1 - Reliability of 129I/I ratios produced from small sample masses
AU - Lu, Z.
AU - Fehn, U.
AU - Tomaru, H.
AU - Elmore, D.
AU - Ma, X.
N1 - Funding Information:
We gratefully acknowledge constructive comments by two reviewers which helped to improve the content of the paper. This work was funded in part by NSF grants EAR-0229100 and OCE-0550122 to UF. PrimeLab, Purdue U is a NSF supported facility.
PY - 2007/6
Y1 - 2007/6
N2 - We report here results of a study on the influence of sample mass on isotope ratios and accuracy of 129I/I determinations in the AMS system at PRIME Lab, Purdue U. Iodine from four samples, two coal-bed methane brines, one surface water sample and a blank, was extracted and precipitated as AgI, following established methods. The resulting samples were subdivided into four sequences of targets, containing between 1.5 and 0.1 mg of AgI. Beam currents for samples with masses above 0.3 mg did not show a dependence on mass, but fell off strongly for smaller masses. The resulting isotope ratios were within the instrumental error limits and did not vary with sample mass, but accuracy decreased for samples with masses below 0.3 mg. The results demonstrate that the presence of 5000 129I atoms in the target is sufficient for making a successful AMS determination, a level considerably lower than for other methods used in mass spectrometry. The ability of producing reliable 129I/I ratios from targets as small as 0.1 mg of AgI enlarges considerably the range of applications possible for this isotopic system.
AB - We report here results of a study on the influence of sample mass on isotope ratios and accuracy of 129I/I determinations in the AMS system at PRIME Lab, Purdue U. Iodine from four samples, two coal-bed methane brines, one surface water sample and a blank, was extracted and precipitated as AgI, following established methods. The resulting samples were subdivided into four sequences of targets, containing between 1.5 and 0.1 mg of AgI. Beam currents for samples with masses above 0.3 mg did not show a dependence on mass, but fell off strongly for smaller masses. The resulting isotope ratios were within the instrumental error limits and did not vary with sample mass, but accuracy decreased for samples with masses below 0.3 mg. The results demonstrate that the presence of 5000 129I atoms in the target is sufficient for making a successful AMS determination, a level considerably lower than for other methods used in mass spectrometry. The ability of producing reliable 129I/I ratios from targets as small as 0.1 mg of AgI enlarges considerably the range of applications possible for this isotopic system.
KW - AMS
KW - I
KW - Small sample
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U2 - 10.1016/j.nimb.2007.01.180
DO - 10.1016/j.nimb.2007.01.180
M3 - Article
AN - SCOPUS:34248171098
SN - 0168-583X
VL - 259
SP - 359
EP - 364
JO - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
JF - Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
IS - 1
ER -