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 herbici des and their degradation products using liquid chromatography-atmosph eric pressure chemical ionization (APCI)-mass spectrometry without any additives in the mobile phase, The APCI detection sensitivity of thes e compounds was maximized when the vaporizer temperature was set at 25 0 degrees 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 mere 2.5-3.0 and 0.12-0.26 ng, respec tively. In a biodegradability test on diuron, small quantities of degr adation products could be determined by the proposed method.