Determination of residues of sulfonylurea herbicides in soil by using microwave-assisted extraction and high performance liquid chromatographic method (original) (raw)
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Plant, Soil and Environment
Although herbicides are used for weed control in the field, their residues can have unfavourable environmental impacts. The objective was to determine the sulfosulfuron herbicide residues in wheat field soil using bioassay and laboratory (HPLC) methods. The two-year experiment was a randomised complete-block design (RCBD) with three replicates using herbicide at control, recommended (26.6 g/ha, D1) and doubled (53.2 g/ha, D2) rates. Soil samples (0–10 cm) were collected randomly at intervals ranging from 0 to 125 days after spraying. Greenhouse experiments (bioassay method) with eight plant species indicated garden cress (Lepidium sativum L.) and corn (Zea mays L.) as the most and the least sensitive ones, respectively. The herbicide residues were stable at D1 up to 90 days after herbicide use, at 1.41 and 0.52 μg/kg in 2019 and 2020, respectively. However, 125 days after herbicide use no residues were observed. With time and for both treatments, soil herbicide residues decreased or...
Weed Research, 1996
logistic curve-fitting procedure, in each case, Rv alues were >0.90 and lack-of-fit tests were clearly non-significant at the 0.05 level. Chisquare tests were used to measure differences between ED.SD'S. The method does not require the pre-germination and selection of seedlings, daily watering or root-washing and results are obtained 7 days from sowing, providing favourable use for routine analyses and large-scale trials.
Effect of Repeated Application of Sulfonylurea Herbicides on Sulfosulfuron Dissipation Rate in Soil
Agronomy, 2020
Accelerated microbial degradation following previous repeated applications of the same pesticide, or another pesticide of a similar chemical structure, is a known phenomenon. Currently there is limited information regarding accelerated degradation of sulfonylurea (SU) herbicides. This study is aimed to evaluate the effect of repeated SU applications on the degradation rate of the SU herbicide sulfosulfuron in soil. The effect of repeated applications of sulfosulfuron on its degradation was assessed in two soils, using a sorghum root elongation bioassay. The effect of consecutive applications of sulfonylurea herbicides over the course of three to four seasons was further examined in controlled environment and a field study. Degradation of sulfosulfuron was determined following its application to soil samples from the field or a controlled environment, by measuring sulfosulfuron residues using liquid chromatography-tandem mass spectrometry. Following the repeated application of sulfosulfuron in the bioassay, the time to reduce sorghum root growth by 50% was shortened by up to 31.6%. However, consecutive application of SUs in the controlled environment had no effect on sulfosulfuron degradation rate constant. Yet, sulfosulfuron degradation rate was enhanced by a factor of 1.35 following consecutive application of SUs in the field, compared to untreated control soil. The data confirm that sulfosulfuron degradation could be enhanced due to repeated sulfosulfuron applications, thus potentially reducing its herbicidal efficacy.
A HPLC-UV detection system was used for determination of sulfosulfuron and tribenuron methyl residues from soils. The soils were fortified with sulfosulfuron and tribenuron methyl at rates of 26 and 15 g a.i. ha− 1 respectively and samples were taken randomly on 0 (2 h), 1, 2, 4, 10, 20, 40, 60, 90 and 120 days after treatment. The final extracts were prepared for analysis by HPLC. The results showed that degradation of both herbicides in the silty loam soil was faster than sandy loam soil. Half-life of sulfosulfuron was ranged from 5.37 to 10.82 days however this value for tribenuron methyl was ranged from 3.23 to 5.72 days on different soils. The residue of both herbicides at 120 days after application in wheat field had no toxicitic effect on lentil. It was concluded that HPLC analysis procedure was an appropriate method for determination of these herbicides from soils.
Environmental Monitoring and Assessment, 2007
Long term stability of sulfosulfuron was investigated in subsoil under the natural wheat cropping conditions. Experiments were conducted by applying a commercial formulation of sulfosulfuron on soil at 50 g/ha and 100 g/ha. To understand the factors influencing the persistence of residues two different experiments were conducted. In one experiment wheat crop was cultivated once at the beginning of the two years study period and subsequently the plots were kept undisturbed for the remaining period. In another experiment cultivation of subsequent crops were continued during the study period. In both the cases sulfosulfuron was applied only once at the beginning of the study. Representative soil samples were collected from the depths viz., 0–5, 15, 30, 45, 60 and 90 cm on different pre determined sampling occasions 50, 100, 200, 300, 400, 500 and 600 days after the application of the herbicide. The collected soil samples were analyzed for the residues of sulfosulfuron. Under the influence of continuous cropping conditions residues of sulfosulfuron were found to be relatively low when compared with the soil samples collected from the agriculture plots maintained without any cultivation. The residues detected are in the range 0.001 to 0.017 μg/g. Samples collected from the depth, at 30 to 45 cm showed higher residual concentrations. Soil samples were also showed the presence of break down products. The data has been confirmed by LC–MS/MS. The relation between residue content of sulfosulfuron and the factors contributing the stability of herbicide concentration were also studied.
Journal of Environmental Quality, 2015
Sulfonylurea herbicides are applied at relatively low rates (3-40 g ha −1) to control weeds in a variety of crops grown in the prairie pothole region of south-central Canada. Because of their high phytotoxicity and the likelihood of their transport in surface runoff, there is concern about impacts of sulfonylurea herbicides to wetland ecosystems embedded in agricultural landscapes. In a previous study, dissipation half-lives (DT 50 values) were determined for three sulfonylurea herbicides (thifensulfuronmethyl, ethametsulfuron-methyl, and metsulfuron-methyl), each possessing a hydrolyzable methyl ester linkage. In the current study, persistence of three sulfonylurea herbicides without a methyl ester linkage was determined in prairie farm dugouts (ponds). The dugouts were fortified with environmentally relevant concentrations (3.3-6.5 mg L −1) of either sulfosulfuron, rimsulfuron, or nicosulfuron. The order of persistence of these herbicides in dugout water from May and June to November and December was nicosulfuron > sulfosulfuron > rimsulfuron, with DT 50 values of 75, 44, and 10 d, respectively. The lack of a methyl ester linkage in these herbicides did not significantly affect their overall persistence relative to those with the ester linkage. In all three dugouts, the decrease in herbicide mass in the water column from water loss via hydrological discharge to groundwater was minimal. The relatively long persistence of these herbicides in the water column of the dugouts reflects the stability of the sulfonylurea linkage to hydrolysis in weakly alkaline waters and indicates not only that microbial and photolytic degradation were low but also that there was little partitioning into sediments.
Analytical Chemistry, 1996
Eight commonly used sulfonylureas (SUs: nicosulfuron, thifensulfuron methyl, metsulfuron methyl, sulfometuron methyl, chlorsulfuron, bensulfuron methyl, tribenuron methyl, and chlorimuron methyl) and deuterium-labeled nicosulfuron (nicosulfuron-d 6), used as an internal standard, were isolated from soil by solvent extraction and identified under quantitative and qualitative ion spray LC/ MS/MS conditions using the selected reaction monitoring (SRM) mode of acquisition. The lower level of quantitation for these SUs in soil was determined at the 0.05 ppb level using a TurboIonSpray adapted LC/MS interface without a precolumn split and optimizing MS/MS tuning conditions for individual SUs. The eight SUs were qualitatively identified and quantitatively determined in soil. The standard curve for each SU was linear from 0.05 to 10 ppb. This SRM LC/MS method demonstrates high sensitivity and high specificity for these SUs in soil and shows at least a 400-fold improvement in sensitivity over previous reports. Acceptance criteria for forensically valid data are suggested for qualitative SRM LC/MS experiments. These include HPLC retention time reproducibility ((2%), at least two and preferably three precursorproduct ions selected, and relative abundance criteria for selected ions ((20% absolute). The trace determination of organic residues in environmental samples presents a challenging analytical problem. In particular, the isolation, identification, and quantitation of polar, labile analytes such as sulfonylureas (SUs) in soil has been shown to be difficult due to a variety of problems. 1-5 Although gas chromatography with conventional detectors has been shown to be applicable in certain instances, 5,6 more recently it has been shown that combined HPLC and mass spectrometry (LC/MS) is a more suitable approach. 1,3,4,7 Recent applications involving the determination of sulfonylurea herbicides have included thermospray LC/MS techniques which have shown a lower level of quantitation
Science of The Total Environment, 2000
Sulfonylurea (SU), imidazolinone (IMI), and sulfonamide (SA) herbicides are new classes of lowapplication-rate herbicides increasingly used by farmers. Some of these herbicides affect both weed and crop species at low dosages and must be carefully used. Less is known about the effect of these compounds on noncrop plant species, but a concentration of 100 ng/L (nanograms per liter) in water has been proposed as the threshold for possible plant toxicity for most of these herbicides. Hence, analytical methods must be capable of detecting SUs, IMSs, and SAs at concentrations less than 100 ng/L in ambient water samples. The authors developed a two-cartridge, solid-phase extraction method for isolating 12 SU, 3 IMI, and 1 SA herbicides by using high-performance liquid chromatography/ electrospray ionization-mass spectrometry (HPLC/ESI-MS) to identify and quantify these herbicides to 10 ng/L. This method was used to analyze 196 surface-and ground-water samples collected from May to August 1998 throughout the Midwestern United States, and more than 100 quality-assurance and quality-control samples.