Development of a home–made device used for collecting an extraction solvent lighter than water after performing air–assisted liquid–liquid microextraction and its application in determination of parabens

Parabens are a group of alkyl esters of p– hydroxybenzoic acid which are widely used as preservatives and antimicrobial agents in cosmetics, foods, beverages, and pharmaceutical products. They have defensive role against multiple categories of microorganisms [1]. Considering this fact that parabens may have harmful effect on human health, development of an analytical method to survey the parabens level in food, cosmetics, and health–care products is necessary.In the present study, a simple and economic analytical method has been reported for simultaneous derivatization, extraction, and determination of some parabens (methyl–, ethyl–, and propylparaben) in different samples using an air–assisted liquid–liquid microextraction technique by use of an organic solvent lighter than water followed by gas chromatography–flame ionization detection. In this work, a new home–made device was used for collecting the extraction solvent. For this purpose, 5 mL of sample solution is transferred into a glass test tube and a mixture of acetic anhydride (as a derivatization agent) and xylene (as an extraction solvent) is added into the solution. After performing the predetermined number of aspiration/dispersion cycles, a cloudy solution is obtained. Then, the mixture is centrifuged for 4 min at 5000 rpm. Then a home-made device (funnel-shaped having a capillary tube) is placed into the tube from the wide section. The collected organic phase is transferred into the capillary tube of the device. Finally, 1 µL of the extraction solvent is removed by a microsyringe and injected into the separation system. Under the optimum extraction conditions, limits of detection and quantification for the target analytes were obtained in the ranges of 0.9–2.7 and 3.0–6.1 ng mL−1, respectively. The enrichment and enhancement factors were in the ranges of 370–420 and 489–660, respectively. The method precision, expressed as relative standard deviation, was within the range of 4–6 % (C= 500 µg ml-1 of each analyte, n=6). The calibration graphs were linear with good coefficients of determination (r2 0.994). The proposed method has been successfully used for the determination of parabens in different cosmetic and hygiene samples, food samples, and personal care products.