The interference of 2-chloro-5-oxo-3-hexene diacyl chloride (COHC) in the detection of strong mutagen MX

The MX formation potential of some compounds belong to benzoic acids, benzoic aldehydes and phenols families was investigated. Only some structures with aldehyde group can form MX, which is inconsistent with other research. A new compound 2-chloro-5-oxo-3-hexene diacyl chloride (COHC) was found. It will seriously interfere with the detection of MX when the GC/MS instrument is operated in select ion monitoring mode because its retention time is very close to that of methylated MX and it has a set of characteristic ions m/z 199, 201, 203, which is widely used in the detection of MX. The detection of COHC has not been reported previously. However, according to its formation mechanism it will widely occur in chlorinated drinking and humic water. Due to the presence of COHC, some of the former research results on MX should be revised.