Colorimetric microdetermination of Vitavax (5,6-dihydro-2-methyl-1,4-oxathiin-3-carboxanilide) residues in crops

Lane, Jo Ann

doi:10.1021/jf60169a030

Cited by 12 publications

(3 citation statements)

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“…Their use in agriculture has made it necessary to devise a sensitive and specific analytical procedure for determining residues in vegetable foods. Lane (1970) developed a method for measuring the residue of carboxin in plant material by hydrolysis and the colorimetric determination of the aniline so formed by coupling with p-dimethylaminobenzaldehyde. Sisken and Newell (1971) increased the quantitative sensitivity required by a residue procedure from 1 to 0.2 ppm by gas chromatographic determination of aniline with a microcoulometric nitrogen detector.…”

Section: Determination Of Residues Of Vitavax and Plantvax In Grainsmentioning

confidence: 99%

Determination of residues of Vitavax and Plantvax in grains

Tafuri¹,

Patumi²,

Businelli³

et al. 1978

J. Agric. Food Chem.

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A gas-liquid chromatographic method using a nitrogen-selective detector is described for the determination of Vitavax and Plantvax residues in grains. Vitavax and Plantvax are extracted from the grains and the extract is cleaned up. Gas-liquid chromatography is applied to Plantvax following the formation of the reduced derivative. The structure of the reduced Plantvax is established by NMR and infrared spectra. The recoveries of Vitavax from fortified grains varied from 87.2 to 92.1% in the range 0.014.20 mg/kg. The sensitivity was such that Vitavax could be detected down to a level of 0.005 mg/kg. Results for Plantvax recoveries showed that the method can be used in grain extracts for levels down to 0.5 ppm for quantitative determination of Plantvax. Below this limit the reduced Plantvax peak rapidly disappeared as concentration diminished.Carboxin (2,3-dihydro-6-methyl-5-phenylcarbamoyl-1,4-oxathiin, I) and oxycarboxin (2,3-dihydr0-6-methyl-5-phenylcarbamoyl-1 ,4-oxathiin 4,4-dioxide, 11), introduced under the trade names Vitavax and Plantvax, are systemic fungicides: the first is mainly employed for the treatment of cereal seeds against smuts and bunts and the second for the treatment of cereals against rusts (Schlor, 1970). A small part of carboxin is oxidized to oxycarboxin in the plants (Chin et al., 1970).Their use in agriculture has made it necessary to devise a sensitive and specific analytical procedure for determining residues in vegetable foods.Lane (1970) developed a method for measuring the residue of carboxin in plant material by hydrolysis and the colorimetric determination of the aniline so formed by coupling with p-dimethylaminobenzaldehyde. Sisken and Newel1 (1971) increased the quantitative sensitivity required by a residue procedure from 1 to 0.2 ppm by gas chromatographic determination of aniline with a microcoulometric nitrogen detector.These methods, which are subject to interference from various aniline-containing compounds, lacked specificity. Chin et al. (1970) studied the metabolism of carboxin by barley and wheat plants and developed a method for its direct determination by using gas chromatography with a microcoulometric sulfur detector. Farrow et al. (1975) reported on the nitrogen-selective detector gas chromatographic determination of carboxin, after it had been extracted from the grain sample with acetone in a Soxhlet apparatus and concentrated.In this last procedure the limit of detection was at best 0.025 ppm, but the recovery was only checked to 0.5 ppm. The grain extracts were not purified and this resulted in an increase in the standing current, a loss of resolution and a shorter column life. Therefore, Farrow et al. (1975) recommended that 20-g samples of the grain be employed for the analysis and that the first 10 cm of column packing be replaced after 50 sample injections. When this method was applied to oxycarboxin, it failed, because the response varied by *25%. In our preliminary trials no peak for oxycarboxin was found when flame or nitrogen selective detectors...

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Section: Determination Of Residues Of Vitavax and Plantvax In Grainsmentioning

confidence: 99%

Determination of residues of Vitavax and Plantvax in grains

Tafuri¹,

Patumi²,

Businelli³

et al. 1978

J. Agric. Food Chem.

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“…The rotary evaporator had a Teflon drive shaft (Model 5001, California Laboratory Equipment Co., Berkeley, Calif.). The steam distillation head is described by Edgerton et al (1967) and Lane (1970). GAS…”

Section: Materials and Equipmentmentioning

confidence: 99%

Determination of residues of Vitavax and its sulfoxide in seeds

Sisken¹,

Newell²

1971

J. Agric. Food Chem.

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Residues of Vitavax (5,athiin-3-carboxanilide), a systemic fungicide and its sulfoxide, are determined in wheat, barley, oats, peanuts, sorghum, flax, and cotton seeds and extracted seed oils. The Vitavax is extracted from the seeds or oils and the extract is cleaned up. Vitavax is hydrolyzed to liberate aniline in a caustic reducing medium. The aniline is distilled and concentrated.An aliquot of the concentrate is injected into a gas chromatograph equipped with a microcoulometric nitrogen detector. The method is designed to minimize the interference from natural components of seed such as tryptophan and its analogs which may also produce aniline. The method is sensitive to less than 0.2 ppm. No residues have been detected in seed harvested from plants grown from treated seed. Yitavax(5,6-dihydro-2-methyl-l,4-oxathiin-3-carboxanilide) is a systemic fungicide useful as a seed treatment prior to planting of wheat, barley, oats, peanuts, sorghum, flax, and cotton. An analytical method sensitive to 0.2 ppm has been developed to measure the residues of Vitavax and its sulfoxide metabolite in seed harvested from plants grown from treated seed.The previously described colorimetric test (Lane, 1970)

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“…Colorimetry. This procedure was used for the determination of total residues of carboxin, extractable, and nonextractable (Lane, 1970).…”

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confidence: 99%