Liquid chromatography–mass spectrometric analysis of phenylurea herbicides and their degradation products using an atmospheric pressure ionization interface

A method was developed for the determination of two phenylurea herbicides and their degradation products using liquid chromatography–atmospheric pressure chemical ionization (APCI)-mass spectrometry without any additives in the mobile phase. The APCI detection sensitivity of these compounds was maximized when the vaporizer temperature was set at 250 °C and a positive-ion detection mode was chosen. Under these conditions, the detection limits (S/N = 3) of these compounds in total-ion and selected-ion monitoring were 2.5–3.0 and 0.12–0.26 ng, respectively. In a biodegradability test on diuron, small quantities of degradation products could be determined by the proposed method.