Persistence and Dissipation of Pyroxsulam in Wheat

An easy and effective method for quantification of herbicide pyroxsulam using LC-MS/MS in multiple reaction monitoring mode has been developed and applied in wheat plant and cropped soil. It involves extraction of the herbicide in acetonitrile followed by clean up using dispersive solid phase extraction (d-SPE) with primary secondary amine (PSA), graphitized carbon black (GCB) (only for plant) and activated MgSO₄. The average recovery ranged between 86–100% for 20, 50 and 100 ng g⁻¹ on all matrices. Persistence of pyroxsulam 4.5% OD has been studied in supervised field trials conducted during 2012–2013 and 2013–2014; applying the developed method for residue analysis. The herbicide formulation was applied @ 18 and 36 g a.i. ha⁻¹ along with untreated control. Following 1^st order kinetics, the half-life of pyroxsulam was found in the range of 1.43–2.55 days on wheat plant and 2.79–3.34 days on soil with both the doses and during both the seasons.