Determination of orotic acid in serum by high-performance liquid chromatography

A simple method for the determination of orotic acid in serum is described. The analyses were carried out using a strong anion-exchange column. Orotic acid was separated isocratically with 0.8 M formic acid (pH 2.8, adjusted with 10 M NaOH)-methanol (65:35, v/v) at a flow-rate of 1.0 ml/min. Absorbance at 275 nm was recorded for quantification. Validation yielded a detection limit of 0.07 micrograms/ml and a quantification limit of 0.25 micrograms/ml. The maximum within-day and day-to-day coefficients of variation were less than 6%. The method has the advantage that samples can be easily prepared.