Identification of glutarylcarnitine in glutaric aciduria type 1 by carboxylic acid analyzer with an ODS reverse-phase column.

A technique for the identification of glutarylcarnitine in urine from a patient with glutaric aciduria type 1 is described. The patient's urine sample was partially purified using an anion exchange column and analyzed by a carboxylic acid analyzer fitted with an ODS reverse-phase column. The chromatogram of the patient's urine sample revealed 3 different peaks, which corresponded respectively to those of carnitine with amino acids, acetylcarnitine and glutarylcarnitine. Following hydrolysis of the sample, the chromatogram had no peaks of acetylcarnitine and glutarylcarnitine but had remarkably amplified peaks of carnitine, acetic acid and glutaric acid. The eluent fraction of glutarylcarnitine from the non-hydrolyzed sample was hydrolyzed and analyzed again. It no longer had the glutarylcarnitine peak on the chromatogram, but had only two separate peaks of carnitine and glutaric acid. This technique simplifies the identification of glutarylcarnitine, in that it requires only removal of organic acids for preparation of samples, and does not require radioisotope or mass spectrometry.