Gas chromatographic method for residue analysis of metsulfuron methyl from soil.

Gas chromatographic method has been developed for the determination of metsulfuron methyl residues from soil. Due to the thermal unstability of this herbicide and its mono methyl derivative, it was derivatized to a dimethyl derivative using diazomethane. Structure of the derivatized product was confirmed by GC-MS. Time for methylation reaction was standardized and 24 h was found to be the optimum time in ethylacetate solvent. Using this method, recovery of metsulfuron methyl from soil was above 70%. Limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.1 μg mL⁻¹ and 0.2 μg g⁻¹ respectively.