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

ABSTRACT

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).