Analysis of oxolinic acid in fish by high-performance liquid chromatography

A simple high-performance liquid chromatographic method for assaying oxolinic acid, a chemotherapeutic agent, in fish tissues has been developed. Nalidixic acid is used as an internal standard. The drugs are separated on an internal surface reversed-phase column. The sample clean-up is minimized. Serum samples are analysed by direct injection on the column; muscle and liver samples are analysed after solid-phase extraction. The recoveries of oxolinic acid from spiked rainbow trout serum, muscle tissue and liver are 99.7, 87.7 and 83.6%, respectively. The lowest measurable amount of the drug is 0.01 microgram/g in all three tissues.