The feasibility of MASE application in the determination of Bensulfuron-methyl (BSM) in soils with different organic matter content, consequently with a different capability to adsorb this herbicide is studied. Hydrolysis experiments were performed to check the significance of degradation under various temperature and time conditions in aqueous-acetonitrile solutions at various pH. Results are shown of the application of the method developed in the determination of BSM in two characteristic Chilean soils (organic matter content 1.4 and 11.4 % and pH 7.2 and 5.1, respectively). The maximum temperature that can be used during the heating program is 60C, where the two main degradation products were undetected and recovery percentages reached 95%.