Hydrogen peroxide in basic media for whole blood sample dissolution for determination of its lead content by electrothermal atomization atomic absorption spectrometry

Hydrogen peroxide in basic media is proposed as a means for dissolving whole blood samples to be analyzed by electrothermal atomization atomic absorption spectrometry, ET AAS. Approximately 2 g of the whole blood sample were directly weighed in a 150 mL volumetric flask; 3 mL of a NaOH 0.2 mol L-1 solution, two drops of 1-octanol, as an antifoaming agent, and 1 mL of 30% volume hydrogen peroxide were added to the flask to promote oxidation. The solution was then manually shaken and after approximately three minutes of shaking, a clear solution, with no apparent suspended solids or greasy layers, was obtained. Distilled-deionized water was used to complete the volume. Ten mu L of the resulting solution along with 10 mu L of a solution containing 5000 mg L-1 of NH4H2PO4 and 300 ing L-1 of Mg(NO3)(2) as a modifier, were injected into transversely heated graphite tubes for lead determination. Both aqueous standards and standard addition calibration curves produced results not significantly different at a 95% confidence limit level. Accuracy of the measurements was assessed by analysis of the 1AEA A-13 (concentration of trace and minor elements in freeze dried animal blood) standard reference material containing 0. 18 mg L-1 lead on a dry basis and by means of recovery tests. Analysis of the IAEA A-13 standard produced 0. 17 +/- 0.02 mg L-1 lead on a dry basis; recovery tests afforded values from 95 to 105%. Ten consecutive measurements of a 5 ppb lead solution gave a characteristic mass of 47.2 pg and a (3S) detection limit of 1.77 mu L-1 Pb. Results obtained from analysis of whole blood samples of volunteer donors covered a lead concentration range between 8 and 21 mu L-1 with a mean value of 11.9 +/- 4.7 mu L-1. (c) 2007 Elsevier B.V. All rights reserved.