A Convenient Method for Epichlorohydrin Determination in Water Using Headspace-Solid-Phase Microextraction and Gas Chromatography

摘要

A simple procedure for epychlorohydrin determination in water is presented. In order to optimize the epichlorohydrin extraction conditions in water using headspace (HS)-solid-phase microextraction (SPME), followed by gas chromatography, an experimental design in two steps is performed. Firstly, a 25-2 fractional factorial design for screening the significant variables is used. Secondly, a central composite design for optimizing them is carried out. The best experimental conditions are the followings: poly(dimethysiloxane)-divinylbenzene coating fiber; 20 min extraction time; 5°C extraction temperature; 300 g/L sodium chloride; and 20 mL HS volume in a 40-mL vial. Using the previous extraction conditions with gas chromatography (GC)-flame ionization detection equipment, a limit of detection (LOD) of 1.8 μg/L and a relative standard deviation (RSD) of 3.8% (for 25 μg/L) are obtained. With a GC electron capture detection equipment the RSD is 6.6% (for 5 μg/L), and the LOD found is lower (0.08 μg/L). The method is applied to the analysis of water from four treatment plants at the entrance and effluent stream. The standard addition method is used to quantitate the epichlorohydrin that is found in the raw water of the three wastewater treatment plants.