Determination of δ-aminolevulinic acid in blood using stopped-flow HPLC

Stopped-flow HPLC (SF-HPLC) was applied to determine δ-aminolevulinic acid in blood (ALA-B) using a reverse phase column after simple pretreating method. The highest fluorescent intensity was obtained when the pretreated sample was doubly diluted with 100 mM sodium acetate (pH 5.0), introduced 60 μl of the sample into the condensing coil at temperature of 98°C, firstly added to 50% acetylacetone in 25% ethanol, and secondary mixed with 10% formaldehyde solution. The detection limit was 2 μg/1 which was 2.5 times higher than that by conventional method, and measuring time per sample was 13 min. Relative standard deviations of 10 blood samples calculated from 4-time determinations per sample for 1 week were within 5 %. ALA-B of 35 lead-exposed and non-exposed workers determined by the SF-HPLC method was closely correlated with the conventional HPLC method (r=0.97). Moreover, this method could prevent an analyzer from exposure to hazardous chemicals such as formaldehyde and acetylacetone.