Abstract
A selective and sensitive analytical procedure for rapid arsenic determination by gas-diffusion flow injection analysis with amperometric detection was developed. The method is based on the arsenite reduction by NaBH4. Derived arsine diffuses through a PTF membrane into the acceptor flow stream and is amperometrically determined on a platinum working electrode. The limit of detection (3σ) at room temperature was 5 µg/dm3 of As(III). The relative standard deviation for a 1 mg/dm3 As(III) standard was 1.96% for six repetitive injections. Arsenic(V) was determined after its prereduction with potassium iodide. Arsenic determination was not interferred with by 1 mg/dm3 Sb(III), 5 mg/dm3 Sn(II), 10 mg/dm3 Se(IV), 1 mg/dm3 As(V), 1 mg/dm3 hydrasine, 1 mg/dm3 Fe(II) or 0.5 mg/dm3 Fe(III) solution. The throughput of this method was 60 analyses per hour. This method was successfully applied to arsenic determination in some power plant waste water samples.
