Simultaneous Determination of Six Parabens in Foods by Matrix Liquid-Phase Dispersion Extraction Combined with High-Performance Liquid Chromatography

Abstract

A novel microextraction method termed matrix liquid-phase dispersion extraction (MLPDE) was presented in this paper. This method was adopted for the extraction of preservatives including methylparaben, ethylparaben, propylparaben, butylparaben, isopropylparaben, and isobutylparaben from different solid food samples. The extracted analytes were subjected to high-performance liquid chromatography (HPLC) analysis immediately. In this method, the food sample (0.50 g) was added previously to a syringe and then rinsed with hot water (45 °C). Subsequently, 2 ml extraction solvent (methanol) was added into the syringe. After ultrasonic extraction, food sample was dispersed into the methanol phase and a cloudy suspension came into being. Under the pressure of the plunger, methanol carrying the target analytes passed through 0.45 μm membrane and 10.0 μl of the eluent was injected into HPLC system. The important parameters including temperature, pH and volume of water, extraction solvent and its volume, sodium chloride addition, sample weight, and ultrasonic time as well as matrix effect were investigated. Under the optimum conditions, recoveries of the studied preservatives ranged from 93.7 % to 107.9 %. The intra-day and inter-day precisions (relative standard deviations) were less than 5.16 % and 5.32 %, respectively. The linear ranges of the method were 0.947–400 mg/kg with the correlation coefficients of 0.9988 to 0.9999. The limits of detection were 0.285 to 1.122 mg/kg. MLPDE is a very simple, rapid, cheap, and efficient method for extraction of nonpolar organic compounds from solid food samples. The proposed method has been successfully applied to the separation and quantification of six parabens in different solid food samples.