Determination of hydrophobicity parameters of ethoxylated nonylphenols by reversed-phase high-performance liquid chromatography

The retention behavior of homogeneous and polydisperse ethoxylated nonylphe nols has been investigated by RP-HPLC as a function of the mobile phase com position. The Linear correlation between the logarithm of capacity factor ( log.k') and the eluent composition was employed to calculate the standard c hromatographic hydrophobicity parameters, log k(w) and phi(0). Correlations were established between the IPP-HPLC retention data and the hydrophile-li pophile properties of the surfactants such as the ethoxylation degree (n EO ), the hydrophile-lipophile balance (HLB) and the oil/water partition coeff icient (K-ow). The results suggest that RP-HPLC may be used as a reliable m ethod to estimate the HLB and K-ow of surfactants.