Rapid Screening of Haloacetonitriles in Water Samples by Optimized Vortex-assisted Liquid–Liquid Microextraction

This paper describes an optimized method for the quick screening of low levels of haloacetonitriles (HANs), a nitrogenous disinfection byproduct. The method is especially geared toward screening of water used for drinking and in swimming pools. The method is based on vortex-assisted liquid–liquid microextraction (VALLME), which is carried out before determination of the gathered samples by gas chromatography-mass spectrometry (GC-MS). Factors that can potentially affect the extraction efficiency of the desired trace chemicals from the gathered sample were enhanced using the Box–Behnken design method. The optimal VALLME parameters for a 10-mL water sample (pH 4, containing 3 g of sodium sulfate), according to the Box–Behnken design method, are extractant 160 μL dichloromethane and vortex extraction time of 1 min at the maximum speed (2500 rpm). The limits of quantitation calculated were 16–35 ng/L. Precision for both intra- and inter-day analysis was also calculated, which was less than 11% on three concentration levels. Mean extraction recovery, otherwise known as trueness, was between 71 and 92%. The developed method was applied successfully to extract HANs from drinking and swimming pool water samples.