Vial position in the determination of chlorophenols in water by solid phase microextraction.

The extraction of chlorophenol from water by headspace solid phase microextraction (HS-SPME) in vials located both vertically and horizontally is compared. The results obtained show that kinetic parameters are clearly affected by how the vial is placed in the analysis of semivolatile compounds. Extraction time for reach the equilibrium was three times lower in the horizontal configuration. An on-line extraction unit coupled to a continuous flow system is used to analyse unmodified ground water samples. In order to increase the high throughput, the analysis time is reduced and the sensitivity increased by making the extraction simultaneously with two fibres. The proposed method is applied to the analysis of spiked river water samples. The precision expressed as relative standard deviation ranges from 3.5 to 4.8%, and the recoveries from 94 to 105%.