DETERMINATION OF IMAZALIL, DIPHENYL, THIA BENDAZOLE AND O-PHEYNLPHENOL IN CITRUS-FRUITS, AND OF IMAZALIL AND THIABENDAZOLE IN BANANA, BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

Analytical methods for the determination of imazalil, thiabendazole (T BZ), diphenyl (DP) and o-phenylphenol (OPP) in citrus fruits and for t he determination of TBZ and imazalil in banana were described. The fou r fungicides were simultaneously extracted with ethylacetate, and dist ributed into two fractions, namely, the imazalil and TBZ fraction and the DP and OPP fraction, by a liquid-liquid partitioning process for c leanup. The fungicides in each fraction were chromatographed on a J'sp here ODS-M80 column with acetonitrile-methanol-water mixture (47:13:40 ) adjusted pH to 2.4 containing 0.01 M sodium dodecyl sulfate as mobil e phase. Detection of DP, OPP and TBZ derived from citrus fruits were carried out be fluorescence detector set at Ex. 285 nm and Em. 340 nm, and imazalil derived from citrus fruits was detected by UV spectropho tometric detector set at 220 nm. Detection of TBZ and imazalil derived from banana, the former was detected at Ex. 305 nm and Em. 350 nm and the latter was detected at UV 220 nm. Recoveries of DP, OPP, TBZ and imazalil from citrus fruits spiked at 20 mu g/g of DP and 2.0 mu g/g o f others were 77.3-81.9%, 84.8-91.8%, 80.1-85.9% and 79.2-81.3%, respe ctively, and recoveries of TBZ and imazalil from banana spiked at 2.0 mu g/g were 80.2% and 78.7%, respectively. The detection limits of DP, OPP, TBZ and imazalil in citrus fruits were 0.5, 0.05, 0.02 and 0.05 mu g/g, respectively, and the detection limits of TBZ and imazalil in banana were 0.005 and 0.02 mu g/g, respectively.