Artigo de Periódico
Determination of mercury in biological samples by cold vapor atomic absorption spectrometry following cloud point extraction with salt-induced phase separation
Fecha
2007Registro en:
0039-9140
v. 72, n. 5
Autor
Dittert, Ingrid M.
Maranhão, Tatiane A.
Borges, Daniel L. G.
Vieira, Mariana A.
Welz, Bernhard
Curtius, Adilson José
Dittert, Ingrid M.
Maranhão, Tatiane A.
Borges, Daniel L. G.
Vieira, Mariana A.
Welz, Bernhard
Curtius, Adilson José
Institución
Resumen
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 H2O2 and HNO3. 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 Na2SO4 to a final concentration of 0.2 mol L−1. Aliquots of the final extract were transferred to PTFE tubes and NaBH4 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.