Cloud point extraction of mercury with PONPE 7.5 prior to its determination in biological samples by ETAAS

ARANDA, P.R., GIL, R.A., MOYANO, S., DE VITO, I.E., MARTINEZ, L.D.

TALANTA

Elsevier

Año: 2008 vol. 75 p. 307 - 311

0039-9140

Cloud point extraction (CPE) has been used for the pre-concentration of mercury, after the formation of a complex with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-PADAP), and later analysis by electrothermal atomic absorption spectrometry (ETAAS) usingpolyethyleneglycolmono-p-nonyphenylether (PONPE 7.5) as surfactant. The chemical variables affecting the separation step were optimized.Under the optimum conditions, i.e, pH 8.5, cloud point temperature 80 ◦C, 5-Br-PADAP = 4×10−5 mol L−1, PONPE 7.5 = 0.2%, sample volume= 1.0 mL, an enhancement factor of 22-fold was reached. The lower limit of detection (LOD) obtained under the optimal conditions was0.01gL−1. The precision for 10 replicate determinations at 2.0 gL−1 Hg was 4.0% relative standard deviation (R.S.D.). The calibration graphusing the pre-concentration system for mercury was linear with a correlation coefficient of 0.9994 at levels near the detection limits up to at least16gL−1. The method was successfully applied to the determination of mercury in biological samples and in certified reference material (QCMETAL LL3).© 2007 Elsevier B.V. All rights reserved.