An improved fabric-phase sorptive extraction protocol for the determination of seven parabens in human urine by HPLC-DAD.

An improved fabric-phase sorptive extraction (FPSE) protocol has been developed and validated herein for the simple, fast, sensitive and green determination of seven parabens-methyl paraben, ethyl paraben, propyl paraben, butyl paraben, isopropyl paraben, isobutyl paraben and benzyl paraben-in human urine samples by HPLC-DAD. The mobile phase consisted of ammonium acetate (0.05 m) and acetonitrile, while total analysis time was 13.2 min. Sol-gel poly (tetrahydrofuran) coated FPSE membrane resulted in optimum extraction sensitivity for the seven parabens. The novel FPSE medium as well as the improved and faster sample preparation procedure resulted in lower limit of detection and quantitation values in comparison with previously reported methods. The separation was carried out using an RP-HPLC method with a Spherisorb C column and a flow rate of 1.4 ml/min. The validation of the analytical method was carried out by means of linearity, precision, accuracy, selectivity, sensitivity and robustness. For all seven parabens, the limits of detection and quantitation were 0.003 and 0.01 μg/ml, respectively. Relative recovery rates were between 86.3 and 104%, while RSD values were <12.6 and 19.3% for within- and between-day repeatability, respectively. The method was subsequently applied to real human urine samples.