To separate and determine a mixture of herbicides containing bentazon, 2,4-D, cyanazine, simazine, atrazine, fluazifop acid, diuron, linuron, and ametryn, an intense study was made to optimize the chromatographic conditions, emphasizing the composition of the mobile phase. After consideration of both analysis time and resolution, the optimum mobile phase to carry out the separation of mixtures of these herbicides was found to be methanol:water 60:40, v/v, pH = 4.6 (adjusted with phosphoric acid). These conditions may be used to analyze mixtures of the cited herbicides present in water samples.23913531363