KOCestimation of deethylatrazine, deisopropylatrazine, hexazinone and terbuthylazine by reversed phase chromatography and sorption isotherms

Abstract
The KOC of three triazine herbicides (atrazine, hexazinone and terbuthylazine) and two triazine degradation products (deethylatrazine and deisopropylatrazine) were derived both by using a HPLC‐reversed phase chromatography method and measuring the KD with sorption isotherms. 21 reference substances and 3 different chromatographic conditions were used to measure the KOC with the HPLC method. The KOC values from sorption isotherms were determined using 6 different soils. The two different KOC values for atrazine, deethylatrazine, deisopropylatrazine and hexazinone derived from the two methods were similar, while those of terbuthylazine were more different. Deethylatrazine, deisopropylatrazine and hexazinone had very low KOC values, even lower than that of atrazine, and this indicates their tendency to move through the soil easily.