A multi-residue method has been developed for the confirmation and quantitation of ten sulfonlylurea herbicides including nicosulfuron,thifensulfuron-methyl,metsulfuron-methyl,sulfometuron-methyl,chlorsulfuron,ethametsulfuron-methyl,tribenuron,bensulfuron-methyl,pyrazosulfuron-ethyl and chlorimuron-ethyl in soil.Samples were extracted from soil with methanol-phosphate buffer(2∶8,V/V)(pH 7.8) under ultrasonic bath.Then the extracts were brought to pH 2.5 with 85% H_3PO_4 and passed under vacuum through a sol...