Use of a stopped-flow pneumatic mixing module to analyze dinitrophenol pesticides. Simultaneous determination of dinoseb and dinobuton.

A kinetic study of the degradation of dinobuton in an alkaline medium has been undertaken by using a stopped-flow pneumatic system. A semiautomatic method for determining dinobuton is proposed for the first time. A detection limit of 0.40 microg mL(-)(1) was calculated. Simultaneous determination of dinobuton and dinoseb can be made by combination of equilibrium and kinetic measurements. The proposed method has been applied to analyze binary mixtures of dinobuton and dinoseb samples with the amount of both components simulating the composition of one undegraded and several degraded dinobuton samples. Also, the procedure has been tested in the analysis of a commercial formulation of dinobuton and the results validated with high-performance liquid chromatography (HPLC).