Rapid and simple analysis of urinary vanilmandelic acid by high-performance liquid chromatography with electrochemical detection.

We examined an analytical method for urinary vanilmandelic acid (VMA) by high-performance liquid chromatography with electrochemical detection from the viewpoint of practical analysis and application. The sample pretreatment in our method is only the dilution of urine samples with citrate buffer. The calibration curve for VMA was linear within the range 0.2 to 20 ng. The detection limit was 50 pg at a signal-to-noise ratio of 3 and the coefficients of variation were 2.30-4.30%. Variations in the urinary levels of VMA, noradrenaline (NA) and adrenaline (Ad) during and after exercise were investigated for 5 males (mean +/- SD, 42.4 +/- 4.3 years of age). The high levels of urinary NA and Ad during 1 hr exercise rapidly decreased after exercise, whereas urinary VMA increased after exercise rather than during exercise and decreased later. The correlation of the urinary levels of VMA and NA for 71 salesman (mean +/- SD, 40.6 +/- 11.7 years of age) in a field study was significantly positive (r = 0.426, p < 0.001). These results suggest that urinary VMA mostly reflects NA, but the excretion rate of VMA is slower than that of NA.