Insecticides and herbicides in soils 87
Figure 3.8 Gas chromatographs of (1) standard containing 6 ng of Metalaxyl (B); (b) extract from
soil A not treated with Metalaxyl; and (c) extract of soil A after addition of Metalaxyl at
20 mg kg
−1 (6 µl of 1 g per 20 ml). Column temperature 190
◦ C. Detector temperature
250
◦ C. Attenuation 50 × 1.
Reprinted from I. Caverley and J. Unwin, Analyst, 1981, 106, 387, © 1981, Royal Society of
Chemistry [180].
Benomyl
Singh and Chiba et al [179] have reviewed methods for the determination of Benomyl
fungicide and its degradation products in soil be chromatography.
Furaloxyl (methyl N(2,6-dimethyl-phenyl) N(2-furyol) alaninate and
Metalaxyl (methyl N-(2,6 dimethyl phenyl)-N-(2-methocyacetyl)
alaninate
Furaloxyl and Metalaxyl are fungicides with residual and systemic activity against
fungi of the order Peronosphorales, which attacks a wide range of commercial crops.
A procedure described by Caverley and Unwin et al [180] is sensitive and rapid and
can be applied to a wide range of agricultural materials. Soils and peat composts are
dried and extracted with acetone in a Soxhlet apparatus, and the extract is analysed,
without clean-up by gas chromatography using a nitrogen-selective rubidium chloride
thermionic detector and a glass column packed with 5% high vacuum silicone grease
on 80–100 mesh Gas-Chrom Q.
The recovery of the two fungicides from peat composts and soils was measured by
addition of stock solutions to the air-dried materials and, after thorough mixing and
standing for 24 hour, extraction with acetone as detailed above. Recoveries range from
78 to 85% at the 200 µg kg
−1 level from Metalaxyl to 70 to 100% at the 10 µg kg
−1
level and 74 to 95% at the 200 µg kg
−1 level and 80 to 90% at the 5 µg kg
−1 level for
Furaloxyl (see Figure 3.8 and 3.9).
Figure 3.8 Gas chromatographs of (1) standard containing 6 ng of Metalaxyl (B); (b) extract from
soil A not treated with Metalaxyl; and (c) extract of soil A after addition of Metalaxyl at
20 mg kg
−1 (6 µl of 1 g per 20 ml). Column temperature 190
◦ C. Detector temperature
250
◦ C. Attenuation 50 × 1.
Reprinted from I. Caverley and J. Unwin, Analyst, 1981, 106, 387, © 1981, Royal Society of
Chemistry [180].
Benomyl
Singh and Chiba et al [179] have reviewed methods for the determination of Benomyl
fungicide and its degradation products in soil be chromatography.
Furaloxyl (methyl N(2,6-dimethyl-phenyl) N(2-furyol) alaninate and
Metalaxyl (methyl N-(2,6 dimethyl phenyl)-N-(2-methocyacetyl)
alaninate
Furaloxyl and Metalaxyl are fungicides with residual and systemic activity against
fungi of the order Peronosphorales, which attacks a wide range of commercial crops.
A procedure described by Caverley and Unwin et al [180] is sensitive and rapid and
can be applied to a wide range of agricultural materials. Soils and peat composts are
dried and extracted with acetone in a Soxhlet apparatus, and the extract is analysed,
without clean-up by gas chromatography using a nitrogen-selective rubidium chloride
thermionic detector and a glass column packed with 5% high vacuum silicone grease
on 80–100 mesh Gas-Chrom Q.
The recovery of the two fungicides from peat composts and soils was measured by
addition of stock solutions to the air-dried materials and, after thorough mixing and
standing for 24 hour, extraction with acetone as detailed above. Recoveries range from
78 to 85% at the 200 µg kg
−1 level from Metalaxyl to 70 to 100% at the 10 µg kg
−1
level and 74 to 95% at the 200 µg kg
−1 level and 80 to 90% at the 5 µg kg
−1 level for
Furaloxyl (see Figure 3.8 and 3.9).