Determination of six veterinary pharmaceuticals in egg by liquid chromatography: Chemometric optimization of a novel air assisted-dispersive liquid-liquid microextraction by solid floating organic drop

Abstract

Two extraction strategies for albendazole, chloramphenicol, trimethoprim, enrofloxacin, oxitetracycline and nicarbazin in egg were optimized for its quantitation by liquid chromatography. First, two designs were built to find out the optimized condition for the air assisted-dispersive liquid-liquid microextraction based on solidification of organic drop: a fractional factorial and a central composite design. The optimum conditions were 1140 µL of water, 125 mg of ZnSO4, 1175 µL of acetonitrile, 1200 µL of methyl alcohol and 740 µL of propanone, using 1.00 g of homogenized egg and 50 µL of 1-dodecanol. Second, two designs were also built to optimize the dispersive liquid-liquid microextraction: a central composite design and a mixture design to set the combination of the re-suspended solvents. The optimum conditions were 1840 μL of acetonitrile and 160 μL of dichloromethane and the re-suspended mixture consisting in acetonitrile and sodium phosphate buffer 10 mmol L−1 pH = 3.50 (30:70 v/v).