Ni P, Guyon F, Caude M, Rosset R
Laboratoire de Chimie Analytique de l'Ecole Supérieure de Physique, Paris, France.
J Chromatogr. 1988 Feb 26;424(2):255-62. doi: 10.1016/s0378-4347(00)81102-0.
An automated liquid chromatographic method for the determination of urinary concentrations of 4-hydroxy-3-methoxymandelic acid (VMA) is described. Urine samples are purified by solid-phase extraction on an anion-exchange cartridge and automated on-line chromatographic elution is carried out using a Varian AASP (advanced automated sample processor) system. The column effluent is monitored with an electrochemical detector using a glassy carbon working electrode. The method allows the determination of VMA in 0.05 ml of normal urine with a relative standard deviation of less than 3%. The analysis time can be shortened by use of back-flushing technique, and the correlation with a classical (but non-automated) VMA analysis method is excellent.
