RESIDUE ANALYSIS AND ANTIACETYLCHOLINESTERASE PROPERTIES OF PROFENOFOS AND DIMETHOATE

Profenofos and dimethoate at half. equal and twice recommended rate were
applied onto cucumber plants. The resleues were determined uSing gas
chromatograph equipped with flame photometric detection. The residue levels of
protenotos on cucumber fruits at harvesling time were 0.54, 1.32. and 1.90 mg/kg for
half, equal, and twice recommended rate. respectively. The corresponding values of
dimethoate were 1.13. 3.85, and 4.60 mglkg, respectively. Profenofos and dimethoate
showed inhibitory effects on rat brain AChE activity with 150 values equal to 16 and 370
11M, respectively. The predicted KI values for profenofos and dimethoate are 1.4 X10^l
and 0.06 X 10) M' min", respectively. The twice-recommended field rate or
dimethoate and profenofos caused 54.1 and 36.4 as a percent Inhibition of control In
vivo of rat brain AChE, respectively. However, profenofos was more potent inhibitor
than dimethoate (In vitro).