| Abstract [eng] |
The objective of the present work was systematic investigation of water-based headspace single-drop microextraction (SDME) technique, its conjunction with capillary electrophoresis, and application for the analysis of volatile inorganic compounds (cyanide and ammonium) in biomedical and environmental samples. Theoretically evaluated and experimentally confirmed that the manipulation in the volatility of the analyte by its chemical modification in the sample and/or in the acceptor phase is the most effective way to enhance the extraction performance in headspace SDME. Maximum extraction efficiency for cyanide was observed in the pH range 4.5–7.5, where cyanide anion is completely transferred into volatile HCN. Complete cyanide recoveries (≥96%) from metal-cyanide complexes were obtained by using two ligand-exchange reagents (ethylenediamine and dithizone). Maximum extraction efficiency was observed by the extraction of ammonia from alkaline samples (pH≥11) with neutral or slightly acidic acceptor phase (pH 3-7). Compared to existing methods water-based headspace SDME is significantly faster and simpler. In addition, proposed technique does not require any sample pre-treatment (deproteinization, acidic/alkaline distillation, etc.) and thus is much less susceptible to interferences. Finally, it offers possibility to choice of a wider variety of solvents and, consequently, enhances the range of extractable analytes as well as the range of analytical methods that can be coupled with SDME. |
