Benzene/water partition constants and thermodynamic parameters estimated from liquid chromatography retention of some herbicides using phenyl-silica stationary phase

"Different elution conditions were used to study the retention behavior of some phenylurea and propanil herbicides in reversed-phase high performance liquid chromatography based on phenyl-silica stationary phase. In order to estimate the benzene/water partition constants of each analyte, the linear relationships between the logarithm of the retention factor and the acetonitrile or methanol content of the mobile phase obtained by isocratic runs were extrapolated for mobile phase containing only water. These values were compared to the octanol/water partition coefficients owing to the lack of data on benzene/water partition constants. The results of the study of column temperature influence have shown a high linear correlation between the logarithm of capacity factor and the reciprocal value of absolute temperature for each studied analyte. The thermodynamic parameters implicated in chromatographic retention were also determined using van’t Hoff method."