Determination of fentin residues in potatoes and celery

Abstract

An analytical procedure is described for the determination of residues of the fungicide fentin (triphenyltin acetate) from potatoes and celery. The method utilises a simple sample extraction procedure involving maceration with hexane followed by a methylation step using a Grignard reaction with methylmagnesium chloride. Samples are determined by packed-column gas chromatography with flame photometric detection. The limit of determination is 2 µg kg^–1, which is well below the maximum concentration of fentin allowed in the substrates concerned (0.1 and 1 mg kg^–1 for potatoes and celery, respectively). At spike levels of 0.1 mg kg^–1, the recovery from potatoes was 84 ± 2%(n= 5); at 0.01 mg kg^–1 this value was 82 ± 7%(n= 7). The blank value for potatoes, bought in a grocery store, was 2.8 µg kg^–1.