Separation of imidacloprid and its degradation products using reversed phase liquid chromatography with water rich mobile phases.

Water rich mobile phases in RPLC are not generally used because of the longer retention times involved when organic modifiers such as methanol or acetonitrile are used. The problem of longer retention times can be addressed using hydrophobic alcohols such as pentanol in low quantities (less than 1%) as organic modifiers. The advantages of using these mobile phases in RPLC for the separation of water soluble and weakly retained congeners is demonstrated through the separation of imidacloprid and its degradation products using a 0.4% pentanol in water mobile phase with 0.2% acetic acid.