Determination of residues of furalaxyl and metalaxyl in nutrient solution, peat compost and soil samples by gas chromatography

Caverly, David J.; Unwin, J.

doi:10.1039/an9810600389

Cited by 6 publications

(3 citation statements)

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“…The metalaxyl content of the soil samples was determined by acetone extraction followed by dual capillary column gas chromatography with thermionic detection ( Caverly & Unwin, 1981).…”

Section: Methodsmentioning

confidence: 99%

Reduced persistence of metalaxyl in soil associated with its failure to control cavity spot of carrots

Davison¹,

McKay²

1999

Plant Pathology

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Metalaxyl was used to control Pythium diseases of carrots in experiments on farms with a history of cavity spot. The first experiment compared the method of application (sprayed, banded or broadcast) and rate (0, 1·5, 3 or 6 kg a.i. ha ¹1 ) one week after sowing. Three additional experiments compared the rate (0, 0·75, 1·5 or 3 kg a.i. ha ¹1 ) and time (sowing, 1-to 2-or 4-to 5-true-leaf stage) of application. In expt 1, the application of metalaxyl, but not the method by which it was applied, increased yield by 20% and significantly reduced the incidence of cavity spot, forking and misshapen carrots. In expts 2, 3 and 4, neither the rate nor time of application affected yield or reduced the incidence of Pythium diseases. Comparison of the sites showed that they differed in past metalaxyl usage. Metalaxyl had not been used on the site of expt 1, but had been used previously at sites 2, 3 and 4. Laboratory experiments were conducted to determine whether these differences in efficacy resulted from reduced sensitivity of Pythium isolates to metalaxyl, or reduced persistence of metalaxyl in soil. ED 50 values showed that there was no reduction in metalaxyl sensitivity. The half-life of metalaxyl was 82 days in soil from expt 1, but was 10 days or fewer in soils from expts 2, 3 and 4. Thus the failure of metalaxyl to control Pythium diseases was associated with reduced persistence in soil, not reduced sensitivity of the target fungi.

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“…The metalaxyl content of the soil samples was determined by acetone extraction followed by dual capillary column gas chromatography with thermionic detection ( Caverly & Unwin, 1981).…”

Section: Methodsmentioning

confidence: 99%

Reduced persistence of metalaxyl in soil associated with its failure to control cavity spot of carrots

Davison¹,

McKay²

1999

Plant Pathology

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“…In previous methods for the determination of fungicides or pesticides in soil, the analyte has been extracted from the sample in a Soxhlet or by means of microwaves, shaking, or sonication, using organic solvents or solvent mixtures: acetone (4,12,13), acetonitrile (1,14,15), benzene (2), cyclohexane (5), ethyl acetate (7), methanol (16)(17)(18)(19), acetonitrile plus water (20), ethyl acetate plus acetone (21), or methanol plus water (3,6,(22)(23)(24). The method described in this paper also uses an organic extractant (ethyl acetate), but, unlike many of the methods cited above, it does not require subsequent partition or chromatographic purification steps, which significantly lengthen the procedures in which they are employed.…”

Section: Introductionmentioning

confidence: 99%

Parameters Affecting Extraction of Selected Fungicides from Vineyard Soils

Rial-Otero

González-Rodríguez

Cancho-Grande

2004

J. Agric. Food Chem.

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This paper describes a sensitive method for the simultaneous quantification of eight commonly used grapevine fungicides in vineyard soils: cyprodinil, fludioxonil, metalaxyl, penconazole, pyrimethanil, procymidone, tebuconazole, and vinclozolin. The fungicides are extracted from the soil sample by sonication with water followed by shaking with ethyl acetate and are quantified by gas chromatography with mass spectrometry. Average extraction efficiencies in a sample of seven spiked, previously fungicide-free soils were > or =79% for all of the analytes, method precisions were > or =17%, and quantification limits were < or =50 microg/kg. However, because recoveries varied considerably from soil to soil, there is a need to control for soil matrix differences (mainly soil pH and exchangeable calcium content); as a consequence, soil fungicide contents must be quantified by the standard additions method. When the method was applied in this way to soil samples from vineyards belonging to the specified wine-growing region of Rias Baixas (Galicia, northwestern Spain) taken at the beginning of October (1 month after the crop's final treatment), levels of fludioxonil as high as 991 microg/kg were found, but at the start of the season (9 months after the previous crop's final treatment) only fludioxonil was detected at levels higher than its limit of quantification (45 and 52 microg/kg).

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“…Metalaxyl (methyl N-(2-methoxyacetyl)-jV-(2,6-xylyl)alaninate) is a fungicide registered for use in the United States on a variety of fruit and vegetable crops. Several methods have been published for the determination of crop residues by gas chromatography with nitrogen-selective detectors (e.g., Caverly and Unwin, 1981;Tafuri et al, 1981; Speck and Dirr, 1980). Cleanup techniques have ranged from simple water partitioning for tomato extracts (Waliszewski and Szymczynski, 1983) to sweep codistillation followed by silica gel chromatography for soil and sunflower foliage extracts (Tafuri et al, 1981).…”

mentioning

confidence: 99%

An enzyme-linked immunosorbent assay for metalaxyl in foods

Newsome¹

1985

J. Agric. Food Chem.

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Determination of residues of furalaxyl and metalaxyl in nutrient solution, peat compost and soil samples by gas chromatography

Cited by 6 publications

References 0 publications

Reduced persistence of metalaxyl in soil associated with its failure to control cavity spot of carrots

Reduced persistence of metalaxyl in soil associated with its failure to control cavity spot of carrots

Parameters Affecting Extraction of Selected Fungicides from Vineyard Soils

An enzyme-linked immunosorbent assay for metalaxyl in foods

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