Determination of trace arsenic in seawater by flow injection- hydride generation inductively coupled plasma mass spectrometry

An inductively coupled plasma mass spectrometry (ICP-MS) instrument equipped with flow injectionhydride generation system was used for the determination of trace arsenic in seawater sample. The accuracy in this method was verified by the analysis of certified reference materials (CRM) of seawater (CASS-4, NASS5). The analytical results agreed with certified value within the range of uncertainty. The expanded uncertainties for CASS-4 and NASS-5 in this experiment were ranged from 6.2% to 6.8% obtained from repeated analyses of the CRMs (n=5). The detection limit of As+ (m/z= 74.9216) in this method was confirmed about 0.01 ug/kg. Linearity obtained from calibration curve of arsenic was excellent (R-2=1). The detection at As+ (m/z=74.9216) and AsO+ (m/z= 90.9165) by using oxygen reaction gas in DRC mode was compared. Sensitivity at AsO+ (m/z=90.9165) was decreased about 25-fold, but the analytical results are the same that at As+ (m/z=74.9216).