Dlmethoate , 



The dlmethoate residue was determined by the same procedures as previ- 

 ously described for the analysis of Bomyl. 



Naled 



Samples were blended with water and transferred with petroleum ether to a 

 tumbling jar. Following the addition of concentrated hydrochloric acid to the 

 jar in the ratio of 4 ml. of acid per 100 g. of sample and enough petroleum 

 ether to make a final ratio of 4 ml. per g. of sample, the samples were tum- 

 bled, anhydrous sodium sulfate was added, and the petroleum ether phase was 

 allowed to separate and was decanted through a filter. A portion of the 

 petroleum ether extract was added to a test tube containing 1/2 ml. of water, 

 and the solvent phase was removed by evaporation. The naled content was 

 determined by a cholinestei*ase- inhibition method described by the California 

 Spray-Chemical Corp. (1) as modified by the procedure used in the disulfoton 

 method. 



PERCENTAGE RECOVERY 



To determine the recovery of the various insecticides, known amounts of 

 each insecticide were added to untreated or check samples before extraction. 

 In addition, known amounts of the metabolites dieldrin and heptachlor epoxide 

 were added to certain samples. The average percentage recoveiTy of insecti- 

 cides added to nontreated check samples of the three forage crops is presented 

 in table 1. 



Table 1. - Recovery of known amounts of insecticide added to non- treated check 

 samples 





Average recovery 



Insecticide added 



Red clover 



Lima bean 

 straw 



Range 



grass 



Aldrin 



Azinphosmethyl ------ 



Percent 

 89.3 



90.7 



80.0 

 88.3 



109.2 



Percent 

 80.0 



95.3 

 88.6 

 85.0 



95.1 

 116.1 



Percent 



81.4 

 81.7 

 84.5 





Diazinon --------- 



r)-t*»1Hfln _____ _ 



Dlmethoate -------- 



Disulfoton -------- 



Heptachlor -------- 



Heptachlor epoxide - - - - 



■Ma 1 «H - 



81.1 

 100.8 





Toxaphene -------- 



Trichlorfon - - 



— 



- 7 - 



