Adsorptive stripping voltammetric analysis of some pterines in human urine

The combined content of biopterin and he separate folic acid content of human urine have been quantitated by phase-selective alternating-current stripping voltammetry at the static mercury drop electrode. The use of disposable C18 cartridge allowed the samples to be separated into two fractions, one containing biopterin and neopterin and the other folic acid. The average concentration of biopterin and neopterin together was 704 ng ml-1; precision, 6.6% (RSD, n=7); mean recovery, 96%. The average concentration of folic acid was 836 ng ml-1; precision, 8.2% (RSD, n=8); mean recovery, 91%.