Determination of mercury in biological samples by cold vapor atomic absorption spectrometry following cloud point extraction with salt-induced phase separation

• Published in: Talanta (Oxford) 2007-07, Vol.72 (5), p.1786-1790
• Main Authors: Dittert, Ingrid M., Maranhão, Tatiane A., Borges, Daniel L.G., Vieira, Mariana A., Welz, Bernhard, Curtius, Adilson J.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Biological samples; Chemistry; Cloud point extraction; Cold vapor atomic absorption spectrometry; Exact sciences and technology; Mercury; O, O-diethyl dithiophosphate; Spectrometric and optical methods; Triton X-114
• ISSN: 0039-9140; 1873-3573
• DOI: 10.1016/j.talanta.2007.02.012

Method development for the pre-concentration of mercury in human hair, dogfish liver and dogfish muscle samples using cloud-point extraction and cold vapor atomic absorption spectrometry is demonstrated. Before the extraction, the samples were submitted to microwave-assisted digestion in a mixture of H 2O 2 and HNO 3. Cloud point extraction was carried out using 0.5% (m/v) ammonium O, O-diethyldithiophosphate (DDTP) as the chelating agent and 0.3% (m/v) Triton X-114 as the non-ionic surfactant. Phase separation was induced after the addition of Na 2SO 4 to a final concentration of 0.2 mol L −1. Aliquots of the final extract were transferred to PTFE tubes and NaBH 4 and HCl were added. The mercury vapor was driven to a non-heated quartz tube for measuring the absorbance. The results obtained with salt-induced phase separation were in good agreement with the certified values at a 95% confidence level. An enrichment factor of 10 allowed a detection limit of 0.4 ng g −1 to be obtained, which demonstrates the high sensitivity of the proposed procedure for the determination of mercury at trace levels.