Redox effects on resin extraction of herbicides from soil1

Abstract

Relative soil aeration affects the surfaces upon which pesticides adsorb and non-ionic resins offer a means of observing and evaluating this factor. A non-ionic resin extractor, developed for pesticide extraction under reducing conditions, was used to adsorb a fraction of the reversibly adsorbed (active portion) herbicides. The extractor consists of cleaned XAD-2 resin encased in a dialysis membrane composed of regenerated cellulose. Anaerobiosis was achieved by incubating soil suspensions with glucose under a 95% N 2 -5% H 2 environment until the redox potential reached − 150 mV. Nine soils with a range of physical and chemical characteristics were examined for atrazine, metribuzin, and alachlor content. Amounts of atrazine, metribuzin, and alachlor extracted from soil ranged to 100, 140, and 75 ng g − 1 , respectively. Resin extractions (RE) conducted under aerobic conditions recovered about 25-50% of the pesticide extractable with conventional solid phase solvent extraction at 60°C (SPE 60 ). Under anaerobic conditions, equal amounts of atrazine were extracted with RE and SPE 60 . Slightly less metribuzin was recovered under anaerobic extraction with the exception of those soils lacking detectable amounts by SPE 60 . Larger amounts of alachlor were extracted with resins under anaerobic conditions than under aerobic conditions but the amounts were not correlated with those determined by SPE 60 . Large amounts of soil organic matter were solublized under anaerobiosis and smaller molecular weight material was extracted with the herbicides. The nature and amounts of co-extracted organic matter varied among soils. RE directly from soil suspensions enabled simultaneous determination of all three herbicides.

Effect of the Presence of Nonionic Surfactant Brij35 on the Mobility of Metribuzin in Soil

“…They indicated the absence of metribuzin in soil samples from soil depths exceeding 0.30 m. Moreover, as the solubility of the herbicide increased, its ability to compete with organic surfaces decreased. This accounts for why, in certain conditions, the migration of metribuzin downward through the soil profile was improved [72].…”

Determination of Alachlor and Its Metabolite 2,6-Diethylaniline in Microbial Culture Medium Using Online Microdialysis Enriched-Sampling Coupled to High-Performance Liquid Chromatography

“…For the analysis of chloroacetanilide herbicide metabolites, high-performance liquid chromatography (HPLC) is preferred because most of the chloroacetanilide metabolites are ionic compounds, which are not sufficiently volatile for analysis by gas chromatography. − However, an appropriate pretreatment and the enrichment of target species are required prior to HPLC analysis. The conventional pretreatment methods for the analysis of alachlor and its metabolites include liquid–liquid extraction (LLE), solid phase extraction (SPE), pressurized liquid extraction (PLE), and solid phase microextraction (SPME). − LLE is not efficient for polar species and ionic compounds and is under criticism for using large quantities of organic solvents, thereby causing pollution accompanied by health risks, in addition to the extensive time-consuming cleanup procedures. The use of SPE has eliminated or decreased most of the disadvantages of LLE.…”