Development of a fiber-in-tube microextraction protocol for gas chromatography–electron capture detection of hexachlorocyclohexanes in water samples

Abstract

A fiber-in-tube microextraction protocol was developed and coupled with gas chromatography–electron capture detector (GC–ECD) for determination of trace hexachlorocyclohexanes (HCHs) in water samples. The developed technique was performed by immersing a PTFE fiber-packed and organic solvent-filled PTFE tube in the stirred aqueous solution. Extraction took place between the solvent permeated fibers and sample solution. The extract was then analyzed by GC–ECD. The effects of fiber quantity, extraction time, agitation, addition of salt and pH of sample solution were investigated in detail. Extraction of the analytes in 8 ml aqueous solution for 20 min yielded enrichment factors of 221–538. The limits of detection (S/N = 3) and the limits of quantitation (S/N = 8) were 2–12 ng l −1 and 6–32 ng l −1, respectively. The precision (R.S.D.s, n = 5) was 0.1% for retention time and 1.8–4.8% for peak height. The developed methodology was applied to the determination of trace HCHs in local river water samples.