Determination of selenium in sediment by isotope-dilution inductively coupled plasma mass spectrometry with an octapole reaction cell

作者：Inagaki K^*; Takatsu A; Nakama A; Eyama S; Yarita T; Okamoto K; Chiba K

来源：Analytical and Bioanalytical Chemistry, 2006, 385(1): 67-75.

DOI：10.1007/s00216-006-0376-7

• selenium
• sediment
• isotope dilution
• ICPMS
• cation-exchange disk filtration

A method is described for determination of selenium in sediment by isotope-dilution inductively coupled plasma mass spectrometry with an octapole reaction cell ( ID - ICP - ORCMS). Sediment samples were digested with HNO3, HClO4, and HF, and the digestion included an elaborate evaporation process to remove bromine from the digested solution. Simple strong cation-exchange disk filtration was used to remove rare earth elements (REE) from the digested solution, because REE2+ seriously interfere with Se isotopes (i.e. Gd-156(2+) with Se-78(+), Gd-160(2+) with Se-80(+)). Addition of acetic acid to the filtrate was examined to improve the sensitivity of ICP ORCMS measurement of Se+ by means of a carbon-enhancement effect. The interfering Ar-2(+) for selenium isotopes were almost eliminated by use of H-2 as reaction gas. Interference from BrH+ formed in the reaction cell was negligible because the Br was removed in the evaporation process. Approximately 99.5% of REE were removed by cation-exchange disk filtration yet more than 99% of Se remained in the filtrate solution. The intensity for Se+ was enhanced approximately fourfold by addition of 5% (v/v) of acetic acid whereas that for Ar-2(+) was barely enhanced. Measured Se-80/Se-78 ratios in unspiked digested solutions of the sample were in good agreement with that for an Se standard solution. The analytical results for Se in the certified reference materials MESS-3 and PACS-1 were in good agreement with their certified values, with small uncertainties.

• 出版日期2006-5