A Single Column Method for the Determination of Urinary-AminolevuIinic Acid

A simple method for determination of urinary-aminolevulinic acid is described. Its advantage over procedures now in use is in the utilization of a single ion-exchange column instead of two ion-exchange columns, with resulting saving of time, labor, and material. The method is accurate and useful in screening for lead poisoning. IT HAS BEEN SHOWN that an increased urinary output of 8-amino-levulinic acid (ALA) appears to be correlated closely with exposure to lead (1-3). Blaeger-Aronsen (2) has reported in animal studies that ALA was increased in the urine only with the administration of lead and not with other industrial toxic trace metals. The procedure of Mauzerall and Granick (4) has become an accepted method for the determination of ALA in urine. This procedure is time-consuming, since it requires the use of two ion-exchange columns. The first column is an anion-exchange resin which separates porphobilinogen (PBG) from urine, and the second, a cation-exchange resin which extracts ALA from urine. After the elution from this column, ALA is converted to 2-methyl-3-acetyl-4-(3-propionic acid) pyrrole by heating with acetyl-acetone. This pyrrole then reacts with dimethylaminobenzaldehyde (DMAB) to produce a cherry-red complex which can be measured spectrophotometrically. #{149}In the routine screening of workers exposed to lead, the determination of PBG is not necessary. This paper will present a single-column modification of the Mauzerall and Granick procedure for the routine determination of urinary ALA. Tn the procedure, it was found that extraction of ALA without prior removal of PBG was found to be satisfactory. Unless the PBG concentration in urine is much highe