Non fatty foods. Determination of benzimidazole fungicides carbendazim, thiabendazole and benomyl (as carbendazim)

Abstract A simple and fast analytical method was developed for the determination of benzimidazole fungicides (benomyl, carbendazim, thiabendazole, and fuberidazole) in soil samples. The analytes were extracted from the soil samples by means of conventional microwave-assisted extraction, using the non-ionic surfactants polyoxyethylene 10 lauryl ether (POLE) and oligoethylene glycol monooalkyl ether (Genapol X-080) as extractants. Determinations were made by using liquid chromatography with direct fluorescence detection. The use of an analytical column Symmetry C-18 offered short retention times of analytes without the need of any pH regulators with mobile phase methanolwater (50 + 50, v/v). The best results were obtained using 5% (v/v) POLE as extractant with recoveries of the fungicides in spiked soil samples between 71 and 105%. The results were compared with those obtained when Soxhlet extraction was applied to the same soil samples.

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Fully Automated Solid-Phase Extraction Cleanup and On-Line Liquid Chromatographic Determination of Benzimidazole Fungicides in Fruit and Vegetables

Journal of AOAC International ◽

10.1093/jaoac/78.5.1267 ◽

1995 ◽

Vol 78 (5) ◽

pp. 1267-1274 ◽

Cited By ~ 14

Author(s):

Maurice Hiemstra ◽

Jeannette A Joosten ◽

Andre de Kok

Keyword(s):

Solid Phase Extraction ◽

Solid Phase ◽

Monitoring Program ◽

Citrus Fruit ◽

Phase Extraction ◽

Benzimidazole Fungicides ◽

On Line ◽

Liquid Chromatographic ◽

Automated Solid Phase Extraction

Abstract A liquid chromatographic (LC) method using fully automated solid-phase extraction (SPE) sample cleanup and on-line LC analysis was developed for determination of the benzimidazole fungicides car-bendazim and thiabendazole in various crops. Preparation of food samples involved extraction with acetone followed by solvent partitioning with dichloromethane–petroleum ether to draw the analytes into the organic phase. The laborious liquid–liquid partitioning cleanup procedure described in the literature was replaced with a fast SPE cleanup using diol-bonded silica cartridges. Automation of the total procedure was achieved by using a commercially available SPE cleanup apparatus (ASPEC). The cleaned-up extract was injected on-line into an LC system with UV and fluorescence detection in tandem. Chromatographic separations were performed with a methanol–phosphate buffer mobile phase (pH = 7) and different polymeric stationary phases. The polymer-based columns performed better than silica-based columns in separating benzimidazole fungicides, and different columns were compared. Results of validation studies with fortified lettuce and citrus fruit are presented. Shewhart control charts of analytical results of control samples demonstrated good performance of the complete system. Sample throughput (extraction, automated SPE, and on-line LC analysis) was about 50 samples per 24 h. Residues of carbendazim and thiabendazole found during our pesticide residue monitoring program in 1992–1994 are reported.

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