Isocratic reversed-phase liquid chromatographic method for the simultaneous determination of (S)-methoprene, MGK264, piperonyl butoxide, sumithrin and permethrin in pesticide formulation.

An isocratic reversed-phase high-performance liquid chromatographic (RP-HPLC) method development for the simultaneous determination of five active ingredients (S)-methoprene, MGK264, PBO, sumithrin and permethrin in a new complex pesticide formulation is described. These active ingredients have similar polarities and contain isomers. The RP-HPLC method development approach began with the selection of a column based on the component structure information, bonded phase, and particle physical characteristics. Second, the mobile phase composition was changed to improve peak resolution and peak sensitivity, especially with analytes containing isomers. Choosing the match between the stationary phase and mobile phase composition, the developed RP-HPLC method not only can simplify the procedure appreciably but also significantly decrease total analysis time and increase peak height. The developed isocratic RP-HPLC method for the analysis of this new formulation was then validated for specificity, linearity, precision, and accuracy. The chromatographic peak identification was identified by LC-MS using the electrospray ionisation in the positive-ion mode.