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 0.03–0.20 mg L−1 with a limit of detection and quantification of 8.2 and 27.3 μg L−1 respectively. The method was successfully applied to the analysis of milk samples with high selectivity.

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► Selective extraction and HPLC analysis of oxytetracycline (OTC) in milk samples.
► Preparation and characterization of a polymer inclusion membrane (PIM).
► Optimization of PIM–HPLC method using a Plackett–Burman experimental design.
► The OTC was isolated and the matrix interferences were eliminated.
► Limit of detection useful for OTC residues analysis in real milk samples (8 ng mL−1).