Lima Bean Straw 



Azlnphosmethyl 



Azinphosmethyl samples were tumbled with hexane: isopropyl alcohol (2:1), 

 and the isopropyl alcohol was removed by washing with distilled water. A poi^ 

 tion of the extract was chromatographed through a dry column of aluminum oxide 

 and the column eluted with benzene. The azinphosmethyl content of the samples 

 was determined by the method of Mengher and coworkers ( 17) . 



Dimethoate 



The samples were extracted by blending with methylene chloride, adding 

 Celite*^ and anhydrous sodium sulfate after blending, and then centrifuging. 

 The centrifuged extract was filtered, concentrated to approximately 10 ml. and 

 chromatographed through a methylene chloride pre-washed Florisil column over- 

 laid with Nuchar-C-190-N. The column was eluted with methylene chloride. The 

 dimethoate residues were determined by the colorimetric method of George and 

 coworkers (9) . 



Other lima bean sti^w samples were blended with chloroform and filtered, 

 and the extract shaken with a mixture of Columbia activated carbon and 200- 

 mesh Florisil, filtered, and concentrated to approximately 50 ml. The extract 

 was shaken with 2 g. of Nuchar-C-190-N:Attaclay (2:1), filtered, and carefully 

 evaporated to dryness. The dimethoate content was determined by the total 

 phosphoiois method of Gigger (11) as modified by George (8) , 



Disulfoton 



For the determination of the disulfoton content of lima bean straw, the 

 samples were blended with chloroform, anhydrous sodium sulfate was stirred 

 into the blended sample, and the chloroform layer was allowed to separate and 

 was decanted through a filter. IVo cleanup and oxidation methods were used. 



A portion of the extract was gravity filtered through a sintered glass 

 funnel containing sodium sulfate and a chloroform-washed and air-dried mixture 

 of aluminum oxide :Nuchar-C-190-N:200-mesh Florisil (1:1:2). The cleaned-up 

 extract was concentrated and oxidized according to the procedure of Patchett 

 and Batchelder ( 22) . The disulfoton residue content was determined by the 

 cholinesterase inhibition procedure of Hensel and associates^' modified to 

 include a 1-hour incubation time instead. of the suggested 2 hours. 



The other procedure used a portion of the extract shaken with 6 g. of a 

 mixture of equal amounts of Nucha r-C-190-N and magnesium oxide, filtered, con- 

 centrated to about 5 ml., and oxidized with perbenzoic acid according to the 

 method of Giang and Schechter (10) . The disulfoton residue content was deter- 

 mined as in the first procedure. 



4/ Hensel, J., Hewitt, H. E. , Sheets, U. M. , and Scott, R. C. 1954. 

 Microestimation of demeton residues. Presented before the Div, of Agr. and 

 Food Chem. , Amer. Chem. Soc. March 1954. 



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