Optimization of mobile phase composition in liquid chromatography

A simple method is suggested for the optimization of the mobile phase composition in isocratic reversed-phase liquid chromatography. The function f = Σ(Rs,i -Rso)2, where Rs,i is the attained resolution for two successive peaks and Rso is the desired resolution for the chosen time of analysis (hence, a chosen capacity ratio of the last component eluted), was used as the chromatographic response function. The minimum of this function, corresponding to the optimum state, can be found rapidly by the statistical simplex method. This approach was applied to the separation of Cu, Co, Ni, Pb, and Hg diethyldithiocarbamates in a reversed-phase system with silica gel-C18.