Turkish Journal of Chemistry, Vol.43, No.6, 1634-1645, 2019
Dispersive liquid-liquid microextraction of parabens from pharmaceuticals and personal care products prior to their determination using HPLC-DAD
Dispersive liquid-liquid microextraction followed by a back-extraction step was combined with HPLC-DAD for the determination of four parabens (i.e. methyl-, ethyl-, propyl-, and butylparaben). Optimum extraction conditions were found as follows: 225 mu L of chloroform, 0.75 mL of ethanol, 7.5 mL of aqueous solution and within an extraction time of 15 s. Back-extraction into 100 mu L of 50 mM sodium hydroxide solution within 20 s resulted in a reversed-phase HPLC-compatible extract. The analytes were separated at 20 degrees C using methanol (A) and water (B), 40:60 (A:B, v/v) as the mobile phase, a flow rate of 1.0 mL min(-1) and an injection volume of 20 mu L. DAD was set at 258 nm to monitor the analytes. Limits of detection and quantitation were as low as 0.1 and 0.3 mu g mL(-1), respectively. Coefficients of determination (R-2) were higher than 0.9950 and percentage relative recoveries were found in the range of 86.5-114.5% for the four parabens from pharmaceuticals and personal care products.
Keywords:Dispersive liquid-liquid microextraction;high-performance liquid chromatography;parabens;personal care products;pharmaceuticals