High performance liquid chromatographic procedure for quantitative determination of urinary delta-aminolevulinic acid as indices of lead exposure.

A high performance liquid chromatographic method for the determination of delta-aminolevulinic acids (ALA) in urine, is described. 2-Methyl-3 carbmethoxy-4-(3-propionic acid) pyrrole was produced by the condensation of ALA with methylacetoacetate (MAA) while heating. The methylacetoacetate could be replaced by ethylacetoacetate. The ALA pyrrole thus obtained was injected into high performance liquid chromatography (HPLC). A stainless-steel column packed with octadecyl silanized silica gel was used. The mixed solution of acetonitrile/50 mM KH2PO4 (adjusted to pH 2.5 with 0.001 volumes of 85 g/dl H3PO4) (20/80) was a favorable mobile phase for the separation of ALA. Amino acetone pyrrole was produced by the condensation of amino acetone with methyl acetoacetate. The amino acetone pyrrole appeared later than ALA pyrrole on HPLC. The method is simple and specific. It has a lower detection limit of 0.2 ng on column. The analysis and quantitative determination of one specimen can be performed within 20 min. Mean ALA concentration of normal urine by HPLC was 1.18 mg/g creatinine.