Extraction procedures for chemical speciation of arsenic in atmospheric total suspended particles.

An arsenic chemical speciation study was performed in 2000, using air filters on which total suspended particles (TSP) were collected, from the city of Huelva, a medium size city with huge industrial influence in SW Spain. Different procedures for extraction of the arsenic species were performed using water, NH2OH.HCl, and H3PO4 solutions, with either microwave or ultrasonic radiation. The best optimised extraction methods were use of 100 mmol L(-1) NH2OH.HCl and 10 mmol L(-1) H3PO4 and microwave radiation for 4 min. High-performance liquid chromatography coupled with hydride generation and atomic fluorescence spectrometry (HPLC-HG-AFS) was employed for determination of the arsenic species. The results from 12 TSP air filters collected on a monthly basis showed extraction was quantitative (94% with NH2OH.HCl and 86% H3PO4). Only inorganic arsenic species (arsenite and arsenate) were detected. The mean arsenite concentration was 1.2+/-0.3 ng m(-3) (minimum 0.3 ng m(-3), maximum 1.8 ng m(-3)). The mean arsenate concentration was 10.4+/-1.8 ng m(-3), with greater monthly variations than arsenite (minimum 2.1 ng m(-3), maximum 30.6 ng m(-3)). The high level of arsenic species in the TSP samples can be related to a copper smelter located in the region.