Determinations of Clopyralid, Picloram, and Silvex at Low Concentration in Soils by Calcium Hydroxide−Water Extraction and Gas Chromatography Measurement

Abstract

Clopyralid (3,6-dichloropicolinic acid), picloram (4-amino-3,5,6-trichloropicolinic acid), and silvex (2-(2,4,5-trichlorophenoxy)propionic acid) at concentrations of 0.0100 μg/g in 14 fortified Alberta soils were determined by calcium hydroxide−water extraction and gas chromatography measurement. Precision of analyses was 1−13%. The herbicide recoveries from the soils with two different fortification procedures were compared. The relationships between recoveries and soil components were examined and discussed. Results from fortified soils, which were extracted immediately following spiking of herbicides, indicated clopyralid recovery of 95.2 ± 6.7% and was independent of the organic matter (0.4−5.3%), clay (3.6−44.2%), sand (16.5−94.1%), or iron (3908−22 455 μg/g) content in the soil. However, picloram and silvex recoveries (58.0−97.8%) were dependent on soil properties with a significant negative trend for being affected by the organic matter content of the soil. Their recoveries decreased with increasing organic matter content of the soil. Detection limits of 0.0025−0.0500 μg/g were herbicide and soil dependent. Results from fortified soil slurries which were extracted after 2−14 days of drying indicated lower herbicide recoveries. The different recoveries from two fortification procedures were discussed in relation to herbicide solubilities, soil-to-water partition coefficients, sorption/desorption, and possible degradation. Keywords: Clopyralid; picloram; silvex; soil components; organic matter content; extraction; calcium hydroxide−water; low concentration; gas chromatography; determination

Optimization and validation of the solid-liquid extraction technique for determination of picloram in soils by high performance liquid chromatography

“…The extract had a very yellowish color, which probably is due to the presence of humic acids from organic matter. In alkaline medium, pH at 8.0, the color of the extract was also yellowish, but less intense, and also because of the presence of humic and fulvic organic matter (Carter, 1993, Tan et al, 1996. This extract was analyzed, while the percentage of extraction found was below the 95.9% found in pH at 7.0.…”

“…In general, the chromatographic techniques are the most used. (Cheng, 1969(Cheng, , 1971McCaall et al, 1972;Biggar & Cheung, 1973;McKone, et al, 1974;Wells et al, 1984Wells et al, , 1987Bovey & Richardson, 1991;Krzyszowska et al, 1994;Lavy et al, 1996;Bruner et al, 1996;Tan et al, 1996;Wells & Yu, 2000;Celis et al, 2002Celis et al, , 2005. Most of these studies were conducted in temperate soils.…”

Highly sensitive analytical method for herbicide clopyralid residue in cattle manure compost with ultraperformance liquid chromatography tandem mass spectrometry

“…[8][9][10][11][12][13][14][15] For analytical methods of clopyralid using gas chromatography (GC), derivatization before determination is necessary. [16][17][18][19] Therefore, the analytical operation is generally complicated. Today, liquid chromatography or ultraperformance liquid chromatography equipped with tandem mass spectrometry (LC-MS/MS 8,9,11,13) or UPLC-MS/MS 10,12,14,15) ) is the prominent method for analyzing pesticide residues in various matrices.…”

Droplets-based microextraction assisted SPME for GC-MS analysis of polar compounds such as clopyralid in water

“…The regulatory analytical methods for the determination of clopyralid from water samples, soil, and compost include gas chromatography (GC) [3][4][5][6][7][8][9][10] and liquid chromatography (LC). [11][12][13][14][15] Since clopyralid has a carboxylic group, the GC analysis required also the derivatization of the analyte as methyl ester, 4,6 1-butyl ester, 3,5,7 pentauorobenzyl ester 8 or silyl derivatives.…”