Determination of Lead in Human Teeth by Hydride Generation Atomic Absorption Spectrometry

Abstract

Problem statement: The determination of lead in human teeth at concentration levels of μg/ml is proposed using Hydride Generation Atomic Absorption Spectrometry (HG-AAS). To do this, 2% (wv) lanthanum chloride solution was employed as matrix modifying reagent to increase sensitivity and remove matrix interferences. Approach: About 100 μL of sample and 100 μL of 3.0% (m/v) NaBH₄ are simultaneously injected into carrier streams. The detection of limit of 0.46 μg L^-1 for Pb was achieved and the relative standard deviation of 3.0% for 10 μg L^-1 lead was obtained. The recovery percentage of the method had been found to be (92.8-100.5%) for known quantities of lead added to teeth sample which were completely recovered. A comparison of the proposed method with standard addition method showed nearly results in the same samples of teeth and results compared with other studies in the world. Results: The method was shown to be satisfactory for determination of traces of lead in teeth samples with excellent accuracy. Teeth analysis reveals that intact teeth contained the highest amounts of lead which provide an evidence that lead may reduce the prevalence of dantal caries. Statistically significant differences (p<0.001) were observed between persons living in city centre and others who living in outskirt for concentrations of lead. Geographical influences are thought to be the main source of variability. No significant difference was shown for lead contents of teeth samples as a function of sex. Conclusion: Statistically significant difference between age groups are seen in the mean value of lead concentrations in human teeth, the concentration of lead increased with age. The differences may be due to the exposure of lead and others factors such as differences in diet and drinking water.