The kinetics of extraction of soil-applied metoxuron by methanol and its biological implications

Raman, Saroja; Rao, P. Chandrasekhar

doi:10.1007/bf00280753

Cited by 7 publications

(2 citation statements)

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“…Under these conditions, the concentration of atrazine, diazinon, and terbutryn remaining in the aqueous solution slowly decreased with time (Figure 4), indicating losses from solution. Although this result was consistent with the long time reported for reaching a real equilibrium partition in soils (2,11,13,22), a measurement time of 24-48 h was considered adequate for subsequent experiments.…”

Section: Resultssupporting

confidence: 84%

“…Batch sorption methods require the separation of the solids from the supernatant liquid, usually by means of filtration (5,10) and/or centrifugation (1,9,11). The separated phases are then analyzed after extraction by either liquid (1,5,10) or gas (9,12) chromatography or, occasionally, direct spectrophotometric methods (13). In some studies, only the liquid phase is analyzed, and the difference between the pesticide fraction so determined and the total amount spiked is assumed as having been sorbed by the soil (1,5,10).…”

Section: Introductionmentioning

confidence: 99%

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Simultaneous Filtration and Liquid Chromatographic Microextraction with Subsequent GC-MS Analysis To Study Adsorption Equilibria of Pesticides in Soil

Ramos

Vreuls

Brinkman

et al. 1999

Environ. Sci. Technol.

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Understanding the sorption equilibria of microcontaminants in soils requires the determination of the adsorbed analytes as well as those remaining in solution. On-line filtration-plus-LC-type microextraction offers an efficient alternative to the time-consuming classical procedures. The feasibility of a new simultaneous filtration-plus-liquidchromatographic microextraction system with subsequent GC-MS to study the partition equilibrium of pesticides in the interface soil-water was investigated. The method allows the determination of the amount of pesticide adsorbed in the soil and that remaining in solution by a single injection of the total slurry. As an example, the adsorption equilibria of selected pesticides, ranging from relatively polar triazines to nonpolar compounds such as hexachlorobenzene or bromophos-ethyl, in an organic soil were studied. Once separated and preconcentrated, the filter and the solidphase cartridge fractions were independently dried by a stream of nitrogen, extracted with methyl acetate, and analyzed by GC-MS. The standard deviations for the total procedure were lower than 6.2% (soil) and 10% (solution). The soil-water partition coefficients calculated for the selected compounds showed a good correlation with published octanol-water partition coefficients (r 2 ) 0.973). This demonstrates clearly the practicality of the proposed methodology for adsorption equilibrium studies.

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Section: Resultssupporting

confidence: 84%