Determination of inorganic arsenic(III) and arsenic(V) in water samples by ion chromatography/inductively coupled plasma-mass spectrometry.
A method was validated for the direct determination of As(III) and As(V) in water samples by ion chromatography/inductively coupled plasma-mass spectrometry. Sample preservation required only dilution with a mobile phase containing a sufficient amount of ethylenediaminetetraacetic acid and acetic acid. Analyses of 6 certified reference materials (CRMs) of various water matrixes, including seawater, demonstrated good method accuracy. The matrixes included 2 natural water samples [National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1643e and NIST SRM 1640], 1 fortified standard solution (TMDA-64), 1 fortified water sample (TM-DWS), and 2 seawater samples (CASS-4 and NASS-5). The sum of As(III) and As(V) in each CRM agreed with the respective certified value for the total amount of As within its stated uncertainty. Quantitative recoveries (96.7-102.1%) were obtained. Satisfactory results were achieved for intraday repeatability [relative standard deviation (RSD = 0.3-5.1%] and interday precision (RSD = 0.7-4.1%). In the study of fortified blanks and fortified CRMs, quantitative recoveries of As(III) and As(V) (92.5-102.6%) were obtained. Interconversion of As(III) and As(V) was not observed under the conditions of sample preservation. International comparability of analytical results was demonstrated by the analysis of 2 interlaboratory proficiency test samples, NY7011 and NY8511, from the New York State Department of Health.
Yip
Yiu-Chung
YC
Government Laboratory, Ho Man Tin Government Offices, 88 Chung Hau St, Kowloon, Hong Kong. ycyip@govtlab.gov.hk
Chu
Hei-Shing
HS
Yuen
Chung-Fai
CF
Sham
Wing-Cheong
WC
D018053:Arsenites / Q000032:analysis*; D002852:Chromatography, Ion Exchange / Q000379:methods; D013058:Mass Spectrometry / Q000379:methods; D012623:Seawater / Q000032:analysis; D012680:Sensitivity and Specificity; D014867:Water / Q000032:analysis* / Q000592:standards
D018053:Arsenites; D014867:Water; C015001:arsenite