Aqueous and acidified slurry sampling approaches in the As, Sb, and Sn determination of urban dust samples by HG-ETAAS

摘要

Conventional solid sample pre-treatments for metals determination by spectroscopy methods involve several disadvantages. To overcome these limitations, an alternative sample pre-treatment such as slurry sampling is being proposed. A critical study of the use of aqueous and acidified slurry sampling techniques was carried out for the direct determination of As, Sb, and Sri in local urban dust samples and a standard reference material, NIST SRM 1649a Urban Dust, by hydride generation coupled with electrothermal atomic absorption spectrometry. The values deter. mined were compared with the certified values of the NIST sample. The values obtained from local urban dust samples were compared with the values achieved by a conventional method based on an acid digestion followed by ICP-MS determination. The influence of mean particle size, chemical composition, and analyte oxidation state were also studied. The recoveries using aqueous slurry sampling for NIST SRM 1649a Urban Dust were 83% and 110% for As and Sri, respectively; however, low recovery (22%) was achieved for, Sb. On the other hand, the recoveries using acidified slurry sampling of NIST SRM 1649a were close to 100% for the hydrideforming elements. The recoveries obtained using aqueous and acidified slurry sampling of the local urban dust samples ranged from 29-41 % for As, 32-66 % for Sb, and 76-81% for Sn from aqueous slurries, and 90 - 100 % for all target metals from acidified slurries.