Determination of Trif luralin, Diallate, Triallate, Atrazine, Barban, Diclofop-Methyl, and Benzoylprop-Ethyl in Natural Waters at Parts per Trillion Levels

Abstract

Abstract A sensitive multiresidue method is presented for the determination of 7 neutral herbicides in natural waters, with practical detection limits between 5 and 100 ng/L(ppt). The extraction was carried out at pH ≼1, using dichloromethane, so that acid-type herbicides can also be incorporated in the future. The entire cleanup procedure involves base partitioning, preliminary cleanup and fractionation on a 10% deactivated Florisil column, and final cleanup of the fractions on an activated Florisil column. However, the cleanup procedure is flexible enough to permit the analyst to use some or all of the cleanup steps, depending on the herbicide levels of interest. Recoveries of the 7 herbicides from distilled and natural water samples were between 82 and 104% at 2 fortification levels. Furthermore, this basic analytical scheme has been demonstrated, separately, to be effective in the determination of other neutral compounds such as PCBs, 18 organochlorine pesticides, and chlorobenzenes and thus has a potential to be developed into a multiclass, multiresidue method.