DETERMINATION OF TOTAL ARSENIC IN URINE BY HYDRIDE AAS AFTER UV-DIGESTION

A method for analysing arsenic in urine samples by Flow Injection Anal ysis-Atomic Absorption Spectrometry (FIA-AAS) after ultra-violet (UV) digestion is developed and validated. The validated method has the fol lowing performance characteristics: limit of detection (LOD) 0.5 mu g L-1, repeatability and reproducibility better than 5% and 10% relative standard deviation (RSD) respectively for arsenic concentrations abov e 3 mu g L-1, linear range 0.5-40 mu g L-1. Validation of the method w as performed by analysing several certified reference materials. Resul ts obtained were well within the certified intervals, Several urine sa mples analysed by UV-FIA-AAS were also analysed by Inductively Coupled Plasma-Mass Spectrometry after High Performance Liquid Chromatography (HPLC-ICP-MS) in order to investigate comparability, Again results we re satisfactory, arsenic concentrations in urine samples did not diffe r from each other significantly. Storage conditions were also studied. Urine samples are best stored in polyethylene containers at 5 +/- 4 d egrees C and are stable in arsenic content for at least 30 days.