Evaluation of solid sorbents for the determination of di-butylphthalate and di-2-ethylhexylpthalate in drinking water

Abstract

The aim of this paper is to test the feasibility of multiwalled carbon nanotubes (MWCNTs) and cigarette filters (CGFRs) as solid adsorbents for pre-concentration of DBP and DEHP in water; and to compare with C₁₈ to investigate which has the best enrichment factor. It was found that cigarette filters exhibited the better recoveries and were therefore the best solid sorbent of the three materials tested, while multiwalled carbon nanotubes were unsuitable for enriching DBP and DEHP on account of its low recoveries. Parameters that may influence the extraction efficiency such as the eluent volume, sample flow rate, sample pH, and the sample volume were optimized. The results showed that the precisions (relative standard deviation, RSD) were 1.40% and 1.72% for DBP and DEHP under the optimal conditions. The detection limits of the developed method could reach 3.1 ng L⁻¹ and 4.3 ng L⁻¹ for DBP and DEHP, respectively, based on the ratio of the chromatographic signal to base line noise (S/N = 3). Satisfactory results were achieved when the proposed method was applied to determine the two target compounds in drinking water with spiked recoveries in the range of 93.6–98.7%. The results indicated that CGFR was a significantly better sorbent to enrich DBP and DEHP in drinking water than the other solid sorbents.

Keywords:

• multiwalled carbon nanotubes
• cigarette filter
• high performance liquid chromatography
• di-butylphthalate
• di-2-ethylhexylphthalate
• drinking water

Acknowledgements

The authors are grateful to the financial support obtained from the Ministry of Science and Technology of the People's Republic of China (No. 2006BAD05A06), the New Century Talent Program of the Ministry of Education of the People's Republic of China (No. NECT-04-0243) and the Fok Ying Tung Education Foundation (Project No. 101073).