A medicolegal study on enzymic fluorometry of choline in human semen.

Studies have been conducted on an enzymic fluorometric method based on an initial rate of reaction for the determination of choline. The reaction system consists of choline oxidase coupled to peroxidase and homovanillic acid. Concentrations of choline as low as 0.1 nmol could be detected by this procedure. The concentration of free choline in normal semen was 18.7 to 29.5 mumol/mL. Free choline in other body fluids was negligible. The choline concentrations in seminal stains maintained at room temperature were not changed during a 30-day period. Those concentrations in seminal fluids kept at room temperature were detected until at least the fifth day.