Chemometric optimization of a novel air assisted-dispersive liquid-liquid microextraction by solid floating organic drop for the determination of six veterinary drugs in egg by liquid chromatography with diode-array detection

CARLA M. TEGLIA; LUCIA GONZALO; MARIA J. CULZONI; HÉCTOR C. GOICOECHEA

Salvador, Bahía

Workshop; VIII Worshop de Quimiometria; 2017

Universidad de UFBA

Around the world, the use of veterinary active ingredients (AIs) during the production of animal-origin food is a common action. Nowadays, the problem lies in the occurrence of AIs in tissues, e.g. eggs, milk, etc. since the effects that traces of AIs could have in the human health are not completely known.The most difficult task in the extraction of AIs in eggs is related to the separation of the analytes from the matrix compounds, which involves breaking up the union between analytes and proteins or lipids. Besides, due to the different physicochemical characteristics of AIs, the extraction of multicompounds is a real challenge. Two extraction methods for albendazole, chloramphenicol, trimethoprim, enrofloxacin, oxitetracycline and nicarbazin (marker residue N,N′-bis(4-nitrophenyl)urea) in egg were optimized in order to determine them by high performance liquid chromatography with diode-array detection (HPLC-DAD). An air assisted-dispersive liquid-liquid microextraction by solid floating organic drop (AA-DLLME-SFO) was improved by building, firstly, a factorial design and, then, a central composite design with volumes of acetonitrile, acetone, methanol and water, and quantity of salt. On the other hand, the response surface methodology (RSM) was firstly applied using a central composite design to improve the volumes of the extraction and the dispersive solvents to find out the optimized conditions for the dispersive liquid-liquid microextraction (DLLME). Then, a mixture design was applied to set the combination of the resuspended solvent. Dependency between the recoveries and the nature of the solvent was observed, suggesting an increase in the recoveries with the proportion of methanol, acetonitrile and buffer.The optimum experimental conditions for the extraction of the analytes in 1.00 g of homogenous eggs were: a) 1840 μL of acetonitrile and 160 μL of dicloromethane, and acetonitrile:sodium phosphate buffer 10 mmol L-1 (pH=3.50) (70:30) as the resuspended mixture for the DDLME method, and b),. 1175 μL of acetonitrile, 1200 μL of methanol, 740 μL of acetone, 1140 μL of water, 125 mg of ZnSO4 and 100 μL of dodecanol for the AA-DLLME-SFO.