title: Determination of mercury in biological samples by cold vapor atomic absorption spectrometry following cloud point extraction with salt-induced phase separation.
abstract: 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(2)O(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(2)SO(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.
authors.affiliation: Departamento de Química-Universidade Federal de Santa Catarina-Campus Universitário, Trindade, 88040-900 Florianópolis, SC, Brazil.
authors.forename: Ingrid M
authors.initials: IM
authors.lastname: Dittert
authors.forename: Tatiane A
authors.initials: TA
authors.lastname: Maranhão
authors.forename: Daniel L G
authors.initials: DL
authors.lastname: Borges
authors.forename: Mariana A
authors.initials: MA
authors.lastname: Vieira
authors.forename: Bernhard
authors.initials: B
authors.lastname: Welz
authors.forename: Adilson J
authors.initials: AJ
authors.lastname: Curtius