Quantitative analysis of total and trimethyl lead in mammalian tissues using ion exchange hplc and atomic absorption spectrometric detection

Measurement of total and trimethyl lead in mammalian tissue is described, using ion exchange/high performance liquid chromatography in tandem with flameless atomic absorption spectrometry for lead-specific detection. All lead forms in whole blood and homogenates of soft tissue—brain, kidney, and liver—were liberated from tissue binding by treatment with dilute (3N) HCl for a period of 18 hr. Trimethyl lead was partitioned into chloroform/ethyl acetate after media neutralization to pH of approximately 4 and saturation with sodium chloride. The extract was chromatographically analyzed on a Partisil SCX-10 cation exchange column, using 0.167M ammonium citrate in methanol:water (70:30) as mobile phase. Fractions of eluate were collected using a programmable fraction collector, and the fractions collected from 3.5 to 5.0 min were analyzed by atomic absorption spectrometry. Total lead in tissue was measured by acid wet digestion and flameless atomic absorption spectrometry. The difference in the values from both analyses provided a measure of any trimethyl lead metabolites.