Determination of oxytetracycline in milk samples by polymer inclusion membrane separation coupled to high performance liquid chromatography

The determination of oxytetracycline in milk samples using a polymer inclusion membrane concept with high performance liquid chromatography (HPLC) was studied. The membranes developed are composed by cellulose acetate as polymer base, Cyanex 923 as carrier and o-nitrophenyl octyl ether as plasticizer. In the optimal conditions, the method exhibits good linearity in the range 0.030.20 mg L?1 with a limit of detection and quantification of 8.2 and 27.3 ?g L?1 respectively. The method was successfully applied to the analysis of milk samples with high selectivity.