Trace determination and occurrence of eight chlorophenylacetonitriles: An emerging class of aromatic nitrogenous disinfection byproducts in drinking water

Two chlorophenylacetonitriles (CPANs) (2-chloro- and 3,4-dichlorophenylacetonitrile), representatives of an emerging class of aromatic nitrogenous disinfection byproducts, were recently identified in chlor(am)inated drinking water with liquid/liquid extraction and gas chromatography/mass spectrometry (GC/MS). Due to their high cytotoxicity, they are potentially significant drinking water contaminants. The detection limit for these two CPANs with the previous method was 100 ng L−1. To search for additional CPAN isomers, a more sensitive method for the simultaneous determination of eight CPANs was developed using solid-phase extraction (SPE)-GC/MS. GC/MS parameters and SPE pre-concentration conditions, including SPE cartridge, eluent type, eluent volume, and sample pH, were optimized. Under optimized conditions, the new method had method detection limits, method quantification limits, and precision ranging from 0.15 to 0.37 ng L−1, 0.50–0.95 ng L−1, and 5.8%–11%, respectively. The recoveries of the eight CPANs ranged from 92% to 102%. The concentrations of the eight CPANs in nine finished drinking waters were determined to be at concentrations ranging from 0.5 to 155 ng L−1. Seven CPANs were detectable in all samples. CPANs were detected at concentrations between 0.8 and 155 ng L−1 in chlorinated waters, and from 0.5 to 15 ng L−1 in chloraminated waters. Across all waters, the sum of all CPANs in chloraminated waters was 13% of that in chlorinated systems.