Automatic in-tube SPME and fast liquid chromatography:: A cost-effective method for the estimation of dibuthyl and di-2-ethylhexyl phthalates in environmental water samples

A 80-cm length commercially available capillary coated with 95% polydimethylsiloxane and 5% polydiphenylsiloxane (TBR-5) was employed to carry out on-line extraction and preconcentration of dibuthyl phthalate (DBP) and di-2-ethylhexyl phthalate (DEHP) in the chromatographic system. The coated capillary was placed between the sample injection loop and the injection needle of an autosampler. Variables affecting the automatic in-tube solid-phase microextraction (SPME) were optimized. A Genesis C-18 (5 cm x 4.6 min i.d., 4 mu m particle size) was employed as analytical column. The achieved limits of detection by use of diode array detection were I and 2.S mu g L-1, respectively. The proposed conditions have been applied to determine those compounds at low ppb levels (<= 250 mu g L-1) in aqueous samples. No matrix effect was found, and recoveries between 85 and 115% were obtained. The precision of the method was good, and the achieved intra- and inter-day variation coefficients were between 5 and 20%. The analysis time per sample was 20 min and any off-line pretreatment of the samples was needed. The taken sample volume was 100 mu L. Data on the application of the described method to the analysis of different water samples are presented. (c) 2008 Elsevier B.V. All rights reserved.