Solid phase extraction and determination of ultra trace amounts of mercury(II) using octadecyl silica membrane disks modified by hexathia-18-crown-6-tetraone and cold vapour atomic absorption spectrometry

A simple method for rapid extraction and determination of ultra trace amounts of mercury(II) ions using octadecyl-bonded silica membrane disks modified with hexathia-18-crown-6-tetraone and cold vapour atomic absorption spectrometry (CVAAS) is presented. Extraction efficiency and the influence of flow rates, pH, and type and smallest amount of stripping acid were evaluated. Maximum capacity of the membrane disks modified by 10 mg of the crown ether was found to be 241 μg Hg2+ ions. The limit of detection of the proposed method is 6 ng per 1000 ml. The method was applied to the recovery of Hg2+ ions from synthetic samples and four different water samples.