Effects of blood and urine on lead analyzed by flameless atomic absorption

About a 10-15% difference was observed by comparing (CDC) bovine blood to a lead standard addition curve using human blood. Results similar to the mean of the CDC survey were obtained by adding lead directly to the bovine blood using standard addition techniques. These results indicate that standard additions of lead should be made to the same matrix and that matrix effects can occur when blood from different species is compared. Analyses of both CDC bovine blood and human blood with added Triton X-100 showed greater sensitivity and reproducibility than similar blood without added Triton X-100. (NH4)2HPO4 greatly enhanced the signal height of lead in urine while nitric acid had a much less effect. The enhancement by (NH4)2HPO4 of the lead signal was at final concentrations greater than 10 g/l. At less than 10 g/l enhancement rapidly decreased. Triton X-100 did not enhance the signal height of lead in urine. Calcium ion and chloride ion did not decrease the lead absorption peak in urine, but magnesium ion did decrease the height of the absorption peak in urine.