Rapid and simple determination of oxytetracycline in chicken products.

A rapid and simple method for determining residual oxytetracycline (OTC) in chicken products (muscle, liver, and eggs) by high-performance liquid chromatography (HPLC) was developed. Samples were prepared by homogenization with acetonitrile-n-hexane (5 + 4, v/v) followed by centrifugation to minimize fat and protein contents. OTC in the acetonitrile layer was free from interfering compounds when examined by HPLC using a LiChrospher 100 RP-8 end-capped column, a mobile phase of acetonitrile-acetic acid-0.01 M disodium EDTA (28 + 2 + 70, v/v/v), and a photodiode array detector. Average recoveries from samples spiked with OTC (0.1, 0.2, and 1.0 ppm) were > 88%, with coefficients of variation between 2.3 and 5.1%. The limit of detection was 0.05 ppm.