Preconcentration and Determination of Trace Amounts of Aromatic Compounds in Non-alcoholic Beer Samples by In-syringe Dispersive liquid–liquid Microextraction

In this paper, a new simple and effective method based on dispersive liquid–liquid microextraction procedure is proposed for rapid and simultaneous separation and preconcentration of ultra trace amounts of benzene, toluene, ethyl benzene and xylenes (BTEX) in non-alcoholic Beer samples. In this experiment, a glass syringe was used as extraction unit. With this simple configuration, the centrifugation step, which is a time consuming step was eliminated and also the possibility of using solvents with density lighter than water as extractant solvent was provided; and therefore applicability of DLLME will be expanded to a wider range of solvents. The influence of extraction parameters, such as kind and volume of extractant and disperser solvents, volume of sample and pH of the sample solution and its ionic strength were investigated and optimized. The best efficiency of extraction acquired using acetone and nonanol as dispersive and extraction solvents respectively. Under the optimum condition, the proposed method provided a linear range (10-1300 μg.L−1) with correlation coefficient (R2 ) of 0.998, and relative recovery of 97.3-101.5%. The limit of detection was in the range of 2.0- 2.8 μg.L−1. At the end, the proposed micro extraction method was successfully applied for the determination of BTEX compounds in a few real non-alcoholic Beer samples.