Simultaneous Extraction of Hydroxyatrazine, Atrazine, and Ametryne from Some Hawaiian Soils
1973
Goswami, Kishore P. | Green, Richard E.
A simple procedure is described for simultaneous extraction from soil of 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine), 2-methylthio-4-ethylamino-6-isopropylamino-s-triazine (ametryne) and their common hydrolysate (hydroxyatrazine = HA). The procedure involves extraction by shaking in acidified methanol, centrifugation, and subsequent quantitative separation of HA from the parent triazines by liquid-liquid partitioning. The pH of methanol was adjusted with 4N HCl to obtain a final pH of 2.5 in the soil extract, using a 1:10 soil/solvent ratio. HA recovery with one extraction was 94% for both Molokai (Typic Torrox) and Hilo (Hydrandept) soils having soil extract pH values of 2.4 and 3.4, respectively. In all cases atrazine and ametryne were quantitatively recovered in soil extracts. After protonation HA was quantitatively separated from the mixture of HA and atrazine or ametryne by partitioning in an aqueous methanolic soil-extract/chloroform system when the water/methanol extract ratio was 1.25. HA extraction from soil was extremely pH dependent. Dissolution of calcium chloride in acidified methanol decreased recovery of added HA from 94% to 76% for Hilo soil but had no effect on % HA recovery from Molokai soil; the electrolyte was found to increase the pH of Hilo soil extract, a result of the net positive charge of this soil at low pH. The recovery of added HA from Ca-montmorillonite was 33%, suggesting that the procedure may be less suitable for soils with high permanent negative charge.
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