Novel and green ultrasonic-assisted liquid-liquid microextraction method based on a nanopolymer for extraction of ferulic acid, gallic acid, cinnamic acid and rutin from vegetable oils

A novel, simple, sensitive and green ultrasonic-assisted liquid-liquid microextraction method based on a synthetic citric acid-glycerol nanopolymer solution was used for the extraction of antioxidant acids (ferulic, cinnamic, gallic acid and rutin) in five kinds of oil samples from vegetables. The synthetic nanopolymer from citric acid and glycerol with absolute molar ratio was synthesized, and its specifications were characterized by (FTIR, DLS, GPC, AFM and NMR). Its solution as a green extractor for oil samples was added to n-hexane containing analytes. Then, the extraction was speeded up by using ultrasonic. After the extraction, phase separation (rich phase/n-hexane phase) was accomplished by using a centrifugation. Rich phase in lower phase was removed by a micro-syringe and injected to reverse-phase HPLC with UV detector. Volume of nanopolymer solution, concentration of nanopolymer, extraction time and temperature of ultrasonic bath were optimum conditions and obtained by response surface methodology. This method has good linear calibration ranges between 0.7 and 1300 mu g L-1, coefficients of determination (r(2) > 0.9831) and low limits of detection between 0.05 and 0.81 mu g L-1. This method was successfully used to determine target analytes in oil samples of olive, almond, sesame, hazelnut and edible with satisfactory inter-intraday precision and recoveries (93.4-107.1%).