Fungicide residues. Part VI. Determination of residues of post-harvest fungicides on citrus fruit by high-performance liquid chromatography

Abstract

A method for determining residues of biphenyl, benomyl, carbendazim, 2-phenylphenol 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.