A new approach for isolation and identification of elecrtophilic mutagens from complex matrix was developed. Thiosulfonic anion was immobilized onto polystyrene beads and used as separation media. Potassium polystyryl-thiosulfonate, prepared from polystyryl-sulfonyl chloride and KHS, was observed to selectively react with model electrophilic mutagens such as alkyl halides, α-chloroketones and α-chloroesters to produce polystyryl-thiosulfonic esters. After separation from other nonreactive organic compounds, the beads then reacted with ethanethiol to produce unsymmetrical ethyl disulfides which are easily detected by GC/MS. For one mutagenic compound, only one unsymmetrical disulfide was found to contain its structure part. Thus, the structure of the parent mutagens could be deduced from that of the unsymmetrical disulfides. The degree of functionalization of the potassium polystyryl-thiosulfonate resin was 1.11 mmol/g. Its reactivity is discussed and its recycling method is reported here.