Measurement of 5-aminolaevulinic acid by reversed phase HPLC and fluorescence detection.

A new method for sensitive measurement of delta-aminolaevulinic acid (ALA) in biological material is described. ALA is derivatized with dansyl chloride, separated by HPLC and estimated using a fluorescence detector. The pretreatment of biological samples includes desamination of L-alpha-aminoacids with L-aminoacid-oxidase before dansylation. The sensitivity of the method is slightly below 1 pmol/injection for standards and the lower limit of quantification is 0.1 mumol/l for plasma and 10 nmol/l for cerebrospinal fluid. Reference values in plasma are 3.53 +/- 1.75 (SD) (n = 43) mumol/l and in packed erythrocytes they ranged from 6 to 26 mumol/l (mean: 14.0 +/- 5.5 mumol/l). In cerebrospinal fluid of non-porphyric individuals less than 2 nmol/l were recovered.