Nine results were reported for selenium from eight laboratories using four different analytical methods: electrothermal vaporization atomic absorption spectrometry (ETAAS), fluorimetry, instrumental neutron activation analysis (INAA), and HGAAS. One result was rejected by a Grubbs test, and those remaining were used for certification.
[3] Nonstandard abbreviations: MMA, methylarsonic acid; DMA, dimethylarsinic acid; AB, arsenobetaine; HGAAS, hydride generation-atomic absorption spectrometry; ICPMS, inductively coupled plasma mass spectrometry; CRM, Certified Reference Material; NIES, National Institute for Environmental Studies; ICP-AES, inductively coupled plasma atomic emission spectrometry; RSD, relative standard deviation; MIP-MS, microwave-induced plasma mass spectrometry; ETAAS, electrothermal vaporization atomic absorption spectrometry; INAA, instrumental neutron activation analysis; and ID, isotope dilution.
Lab Analytical ID Sample pretreatment n method Remarks 01 Pressurized HN[O.sub.3] 24 ICPMS Matrix matching, digestion Y as internal standard HN[O.sub.3]/HCl[O.sub.4]/ 4 ICP-HRMS (a) As(V) standard [H.sub.2]S[O.sub.4] addition digestion HN[O.sub.3]/HCl[O.sub.4]/ 4 MIP-MS As(V) standard [H.sub.2]S[O.sub.4] addition digestion 02 HN[O.sub.3]/HCl[O.sub.4]/ 6 ETAAS [H.sub.2]S[O.sub.4] digestion, solvent extraction, solid-phase back extraction 03 HN[O.sub.3]/HCl[O.sub.4]/ 6 HGAAS [H.sub.2]S[O.sub.4] digestion 05 Reconstitution and 12 INAA re-freeze-drying an aliquot 10 HN[O.sub.3]/HCl[O.sub.4]/ 5 HGAAS [H.sub.2]S[O.sub.4] digestion (a) HRMS, high-resolution mass spectrometry.