Liquid chromatography-electrospray tandem mass spectrometry of acidic monoamine metabolites

A new method based on liquid chromatography-tandem mass spectrometry has be en developed for the determination of monoamine metabolites, i.e., homovani llic acid (HVA), vanilmandelic acid (VMA), 3,4-dihydroxyphenylacetic acid ( DOPAC) and 5-hydroxyindoleacetic acid (5-HIAA) in human urine. Analytes wer e separated on a C-16 amide (5 cm, 5 mu m) column and ionized by negative i on electrospray. Operating in the selected-reaction monitoring mode, linear ity was established over three-orders of magnitude and limits of detection were in the range 30-70 mu g/l. Precision calculated as RSD was within 0.8- 5.2% for all intra- and inter-day determinations. The method was applied to the quantitative analysis of monoamine metabolites in 700 urine samples fr om occupationally (adults) and environmentally (both children and adults) e xposed people living in areas with different soil contamination from lead. The urinary excretion of monoamine metabolites was significantly higher (P< 0.001) in the subgroup of children living in polluted areas as compared to the control group (HVA, 6.03 vs, 4.57 mg/g creatinine; VMA, 5.33 vs. 4.37 m g/g creatinine; 5-HIAA 3.24 vs. 2.45 mg/g creatinine). In adults belonging to both groups of subjects occupationally and environmentally exposed, no d ifferences were detected in the urinary concentration of monoamine metaboli tes. However, adults showed lower values of HVA (2.57 mg/g creatinine), VMA (2.17 mg/g creatinine) and 5-HIAA (2.09 mg/g creatinine) as compared to ch ildren groups. (C) 2000 Elsevier Science B.V. All rights reserved.