A rapid, colorimetric, procedure for determination of fenitrothion.

Fenitrothion in formulations and on grains is determined colorimetrically as 4-nitro-3-methylphenoxide, after hydrolysis at room temperature catalysed by alkaline peroxide. Interferences in determination of residue levels are removed by filtration of commodity extract through basic alumina or by barium chloride plus excess oxidant.