Abstract: | Abstract A new method is described to analyse a binary mixture of atrazine and chlorpyrifos, using first-derivative spectrophotometry for atrazine and first derivative of the ratio spectra for chlorpyrifos. The procedure does not require any separation step. Calibration graphs were linear up to 15 μg.mL?1 of atrazine and to 10 μg.mL?1 of chlorpyrifos. The method has been applied to determine both compounds in pesticide formulations, in soils and waters. |