A Combination of Factorial Design, Off-line SPE and GC-MS Method for Quantifying Seven Endocrine Disrupting Compounds in Water

A sensitive and reliable analytical method for the simultaneous determination of seven endocrine disrupting compounds (EDCs) in water was developed and validated. This quantification method is based on solid phase extraction (SPE) followed by a derivatization with BSTFA and finally the seven EDCs were analyzed by gas chromatography-mass spectrometry (GC-MS). A 2(3) factorial design was used to optimize the extraction procedure. Three factors, namely sample volume, elution solvent, and pH of sample were investigated using Doehlert matrix. The optimal conditions of SPE method were: HLB cartridge, 540 mL of water sample with a pH 8 and 10 mL of mixture of ethyl acetate/acetone with a ratio of (55/45, v/v) in the elution step. For validation of the technique, accuracy, precision, detection and quantification limits, linearity, sensibility and selectivity were determined. Extraction recovery of these seven EDCs were above 90% with relative standard deviations (RSD) <= 2%. The method limit of detection and limit of quantification were in the range of 0.33-3.33 and 1-10 ng/L, respectively.