Determination of Phthalate Esters in Water Samples by Solid-phase Microextraction and High Performance Liquid Chromatography

A solid-phase microextraction(SPME)method coupled with HPLC/UVwas developed and validated for the determination of five phthalate esters(dimethyl-,diethyl-,di-n-butyl-,butylbenzyl-,di-2-ethylhexyl-and di-n-octyl phthalate)in water samples.Five different types of SPME polymer coatings were investigated.On the basis of orthogonal experiments with three factors,three levels and nine groups,the SPME experimental conditions,such as extraction time,effects of ion strength,and thermal desorption time were optimized.The optimized parameters for the SPME method were as follows:65μm PDMS/DVB fiber,room temperature,stirring rate of1100r/min,extraction time of30min,thermal desorption time of5min,and use of acetonitrile as desorption solution.Acetonitrile-water(60∶40by volume)was used as the mobile phase with gradient elution on the C 18 reversed phase chromatography column,and the flow rate was1mL/min.The detection wavelength was228nm with the UV-VIS detector.The linear range of the method was determined to be from0.50to80.00μg/L,and the detection limit varied from0.11to2.20μg/L.The relative standard deviation(n=6)was2.5%-9.6%.This method was used for determination of phthalate esters in water sample,such as tap,boiled and rain water,and the recoveries ranged from82%to128%.The method is fast,convenient,sensitive,solvent-free,and suitable for the determination of trace phthalate esters in environmental water samples.