Derivative spectrophotometry in the analysis of mixtures of phenols and herbicides

Derivative spectrophotometry (zero-crossing technique) was applied to the d etermination of selected phenols and herbicides in two-component mixtures. Methyl- and chlorophenols (3-methylphenol, 2,3- and 3,4-dimethylphenol, 2,5 -, 2,6- and 3,4-dichlorophenol and 2,4,5-trichlorophenol) and triazine, ura cil and urea herbicides (simazine, propazine, hexazinone, bromacil and meto xuron) were examined. The RSD values ranged between 0.05 and 4% and the rec overies obtained were between 97 and 110%. The developed derivative spectro photometric method was also applied as a complementary technique for the se paration of overlapping peaks of sample compounds obtained by HPLC with dio de-array detection. Metoxuron and 3-methylphenol, metoxuron and 2,5-dichlor ophenol and simazine and 2,6-dichlorophenol were determined simultaneously by this method at the level of 1 x 10(-3) g l(-1).