Determination Of Thiabendazole Residues Research Articles

Simple and fast spectrophotometric determination of low levels of thiabendazole residues in fruit and vegetables after pre-concentration with ionic liquid phase microextraction

ABSTRACTThere is a great importance of monitoring thiabendazole (TBZ) residues in fruits and vegetables to ensure food safety. Therefore, a new ionic liquid (IL) phase microextraction method using IL, 1-butyl-3-methylimidazoliumhexafluorophosphate [C4mim][PF6], as extracting solvent is proposed for simple and fast determination of low levels of TBZ in fruits and vegetables by spectrophotometry. The method is based on selective complex formation of TBZ with Cu(II) ions in presence of PF6– as counter ion at pH 5.5, and then microextraction of the complex into the fine micro-drops of IL phase. After optimisation of variables affecting microextraction efficiency, the analytical parameters of the method were determined by calibration curves. The method exhibits a linear relationship (0.3–280 μg L−1), low detection limit (0.1 μg L−1), good intra- and inter-day precision (2.4–4.5% as RSDr%, 2.1–5.6% as RSDR%), good recovery (≥95.1–98.2%) and high sensitivity enhancement factor (150) by solvent-based calibration curve. It allows a detection limit of 0.24 μg L−1 and a range of 0.8–250 μg L−1 by the matrix-matched calibration curve. After validation, the method was successfully applied to the determination of TBZ residues with method quantification limits in fruit and vegetables of 2.0 and 2.5 µg kg−1 with and without adding polyvinylpyrrolidone (PVP-15) solution. Recoveries range from 85.5% to 98.2% after spiking (10, 50 and 100 µg kg−1, n: 3).

Determination of Thiabendazole Residues in Whole Citrus Fruits by Liquid Chromatography with Fluorescence Detection

An existing liquid chromatographic (LC) method for determination of thiabendazole (TBZ) residues in or on whole green bananas and potatoes was applied to whole, unwashed citrus fruits. The method is applicable for determining TBZ residues in whole oranges, grapefruits, tangerines, and lemons. TBZ is extracted from citrus homogenate with ethyl acetate, and the extract is cleaned up on a cation-exchange, solid-phase extraction column. The purified extract is analyzed by LC with a cation-exchange column and fluorescence detection. Average recovery of TBZ from whole citrus fruits fortified with TBZ at 0.05-20 ppm was 96%. The assay provides a simple, rapid, and sensitive method for monitoring TBZ residues in whole citrus fruits.

Determination of Thiabendazole Residues in White and Sweet Potatoes by Liquid Chromatography with Fluorescence Detection

A liquid chromatographic (LC) method was developed for determination of thiabendazole (TBZ) residues in or on whole, unwashed white potatoes (Solanum tuberosum) and sweet potatoes (Ipomoea batatas). TBZ is extracted from the potato homogenate with ethyl acetate and the extract purified and concentrated on a cation-exchange, solid-phase extraction column. The extract is analyzed for TBZ residues by column LC with a cation-exchange column and fluorescence detection. Recoveries of TBZ from whole white potatoes fortified with TBZ at 0.05-20 ppm and from whole sweet potatoes fortified with TBZ at 0.005-0.1 ppm averaged 100 and 94%, respectively. The method is also applicable for quantitation of TBZ residues in white potato waste (dried peel) used as an animal feed additive. The present method for monitoring TBZ residues in white and sweet potatoes and white potato waste (dried peel) is simple, rapid, and sensitive.

Determination of thiabendazole residues in waters by solid-phase spectrofluorometry.

A new, sensitive and simple spectrofluorometric method for the determination of thiabendazole (TBZ) residues was studied. TBZ on Sephadex G-15 gel, pH 4.70 acetate buffer, is fixed to give fluorescence. The fluorescence of the gel-TBZ system, packed in a 1-mm quartz cell was measured directly using a solid-surface attachment. The applicable concentration range was 1.5-10.0 ng.mL-1 with a relative standard deviation of 1.4% and a detection limit of 0.1 ng.mL-1. The method was applied to the determination of thiabendazole in natural, waste, sea, and residual waters (98-100% recovery). The method is more sensitive and selective than other methods described in the literature. The presence of other fluorescent pesticides (dichlone, carbaryl, morestan, o-phenylphenol) with similar spectral features (lambda exc and lambda em neighboring to excitation and emission wavelengths of the TBZ) did not cause interference.

Determination of thiabendazole residues in meat by HPLC using ultraviolet and fluorometric detection

An HPLC method is described for the residue analysis of thiabendazole in meat. The recovery varies from 62 to 75%. Thiabendazole is extracted from the tissue using 3 mol HCl, eluted from the Extrelut-20 column with dichloromethane and then injected onto a C18 column. The optimum conditions for detection are described using ultraviolet and fluorescence spectroscopy. The sensitivity is such that thiabendazole can be determined at a level of 5 micrograms/kg meat. The absolute detection limit with fluorometry is 100 pg.

Determination of thiabendazole residues in potatoes using high pressure liquid chromatography

This paper describes a method for the extraction, purification and quantification by high pressure liquid chromatography using fluorimetric detection, of thiabendazole residues from potatoes. Bonded silica sorbent extraction columns (diol phase) are used for sample clean up, resulting in a rapid and accurate analysis.

Determination of thiabendazole residues in marmalades by high-performance liquid chromatography

Determination of thiabendazole residues in marmalades by high-performance liquid chromatography

Determination of thiabendazole residues in fruits by high-performance liquid chromatography and their confirmation after p-nitrobenzyl derivative formation.

Determination of thiabendazole residues in fruits by high-performance liquid chromatography and their confirmation after p-nitrobenzyl derivative formation.

Beitrag zur Analytik von Thiabendazol auf Zitrusfrüchten und Bananen

With regard to routine analyses in market control, the authors recommend two methods (according to the expected amounts of active principle) for the determination of thiabendazole residues on citrus fruits and bananas. The ultraviolet spectrophotometric method is preferable in determining thiabendazole contents of more than 1 p.p.m., if the cleaning operations described are respected. For the detection of thiabendazole and for the determination of amounts of less than 1 p.p.m. (the tolerance limit being 0.2 p.p.m. for pomes, berries, stone fruits, kernel fruits and also for potatoes) the thin-layer chromatographic method seems likewise to be suited (also in considering that it is semi-quantitative by nature); especially since the spectrophotometric method yields values by 0.2 p.p.m. too high (due to the measurement of residual absorption of vegetable constituents). The authors are of opinion that such an error must be considered to be too high for contents lower than 1 p.p.m.

Thin Layer Chromatographic Separation and Spectrophotofluorometric Determination of Thiabendazole Residues on and in Citrus

Abstract A thin layer chromatographic (TLC)-spectrophotofluorometric method was developed for quantitative determination of thiabendazole on and in citrus. Whole citrus fruits are surface stripped with ethyl acetate and a concentrated aliquot is separated by TLC. Wholefruit blends, juice, oil, and dried citrus pulp cattle feed are extracted with ethyl acetate, partitioned into 0.1N HC1, and then partitioned into ethyl acetate-chloroform from an aqueous basic solution prior to TLC. Thiabendazole is eluted from the chromatogram with acidified methanol and the intensity of fluorescence is compared to standards similarly chromatographed and measured. The method is accurate in determining thiabendazole content ranging from 0.2 to 6 ppm. Recoveries of thiabendazole from fortified samples were 95–99% for surface strippings and 70–91% for rind and pulp extractives. No significant difference was found between residue values determined by the TLC method and by the Merck method. TLC eliminates citrus constituents which occasionally interfere with the Merck method.