ARSENIC DETERMINATION IN SALINE WATERS UTILIZING A TUBULAR MEMBRANE AS A GAS-LIQUID SEPARATOR FOR HYDRIDE GENERATION INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

A tubular silicone rubber membrane is evaluated as a gas-liquid separa tor for the determination of arsenic in saline waters aia HG-ICP-MS. T he system was optimized in terms of NaBH4 and HCl concentrations. The intermediate gas and carrier gas were optimized in terms of sensitivit y and stability. The pre-reduction of As-V in standard solutions and r eference materials was investigated using KI and KI plus ascorbic acid sample treatments. The KI plus ascorbic acid treatment produced a sim ilar response for Asm and As-V independent of the matrix. The KI plus ascorbic acid treated samples could be held for 21 days without signif icant response changes. The detection limit was 92 pg based on 7 repli cate injections of a 400 pg standard. The overall system was evaluated by analysing two reference materials, NASS-4 and SLEW-2. Precision an d recovery data were collected on three estuarine samples.