Multi-walled carbon nanotubes packed cartridge for the solid-phase extraction of several phthalate esters from water samples and their determination by high performance liquid chromatography

Being suspected to have carcinogenic and estrogenic properties, the determination of phthalate esters in various environmental samples is very important for environmental risk assessment. In the present paper, a new solid-phase extraction system for HPLC determination of di-ethyl-phthalate, di-n-propyl-phthalate, di-iso-butyl-phthalate, and di-cyclohexyl-phthalate was developed. The four analytes were quantitatively adsorbed on multi-walled carbon nanotubes packed cartridge, then the analytes were quantitatively desorbed with acetonitrile, finally the analytes in acetonitrile eluate were determined by HPLC. Parameters influencing the extraction efficiency such as volume of sample solutions and eluent volume, were examined. Under the optimized conditions, detection limits of 0.18-0.86 ng ml(-1) were achieved for four phthalate esters. The proposed method had been used to determine the four phthalate esters in tap water, river water, and sea water samples. No phthalate esters were found in the river water and sea water samples. For the case of tap water sample, di-ethyl-phthalate, di-n-propyl-phthalate, and di-cyclohexyl-phthalate were not found, only 2.0 ng ml(-1) of di-iso-butyl-phthalate was found. The accuracy of the proposed method was tested by recovery measurements on spiked samples, the recoveries of 80.3-104.5% were obtained in most cases. (C) 2003 Elsevier B.V. All rights reserved.