Arsenic determination in saline waters utilizing a tubular membrane as a gas–liquid separator for hydride generation inductively coupled plasma mass spectrometry

Abstract

A tubular silicone rubber membrane is evaluated as a gas-liquid separator for the determination of arsenic in saline waters via HG-ICP-MS. The system was optimized in terms of NaBH₄ and HCl concentrations. The intermediate gas and carrier gas were optimized in terms of sensitivity and stability. The pre-reduction of As^V in standard solutions and reference materials was investigated using KI and KI plus ascorbic acid sample treatments. The KI plus ascorbic acid treatment produced a similar response for As^III and As^V independent of the matrix. The KI plus ascorbic acid treated samples could be held for 21 days without significant response changes. The detection limit was 92 pg based on 7 replicate injections of a 400 pg standard. The overall system was evaluated by analysing two reference materials, NASS-4 and SLEW-2. Precision and recovery data were collected on three estuarine samples.