Hydrogen peroxide in basic media for whole blood sample dissolution for determination of its lead content by...

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 2g of the whole blood sample were directly weighed in a 150mL volumetric flask; 3mL of a NaOH 0.2molL(-1) solution, two drops of 1-octanol, as an antifoaming agent, and 1mL 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 muL of the resulting solution along with 10muL of a solution containing 5000mgL(-1) of NH(4)H(2)PO(4) and 300mgL(-1) of Mg(NO(3))(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 IAEA A-13 (concentration of trace and minor elements in freeze dried animal blood) standard reference material containing 0.18mgL(-1) lead on a dry basis and by means of recovery tests. Analysis of the IAEA A-13 standard produced 0.17+/-0.02mgL(-1) lead on a dry basis; recovery tests afforded values from 95 to 105%. Ten consecutive measurements of a 5ppb lead solution gave a characteristic mass of 47.2pg and a (3S) detection limit of 1.77mugL(-1) Pb. Results obtained from analysis of whole blood samples of volunteer donors covered a lead concentration range between 8 and 21mugL(-1) with a mean value of 11.9+/-4.7mugL(-1).