Substances: Allethrin (ZCVAOQKBXKSDMS-UHFFFAOYSA-N) Cyphenothrin (FJDPATXIBIBRIM-UHFFFAOYSA-N) Empenthrin (YUGWDVYLFSETPE-JLHYYAGUSA-N) Chlorpyrifos-methyl (HRBKVYFZANMGRE-UHFFFAOYSA-N) Keywords: trace analytics stream pyrethroids Insecticides