A method for determining residues of biphenyl, benomyl, carbendazim, 2phenylphenol and thiabendazole is presented. Samples are extracted by refluxing with dilute hydrochloric acid, the biphenyl and 2-phenylphenol being steam distilled and collected for determination separately. Benomyl is converted into carbendazim and both carbendazim and thiabendazole are separated from interfering co-extractives by partitioning with chloroform under acidic and basic conditions. Thiophanate-methyl can also be determined after conversion into carbendazim but the conversion is not quantitative, The fungicides are determined by high-performance liquid chromatography using an ultraviolet spectrophotometric detector.

A simple method for determining residues of carboxin in grain is presented. The carboxin is extracted from the sample with acetone in a Soxhlet extraction apparatus and, after concentration of the extract, is determined by gasliquid chromatography using a nitrogen-selective detector. The presence of carboxin is confirmed by the use of a sulphur flame-photometric detector.

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