| Summary: | 碩士 === 淡江大學 === 化學學系 === 90 === Organophosphate insecticides are widely used in many agriculture applications. Organophosphates had the advantage of effectiveness and high decomposing rate. However, both of organophosphate and it metabolites possess high neurotoxin. In a severe case, organophosphate pesticides may result in cholinesterase inhibition and/or death. Dimethoate, one of the organopgosphorus pesticides, was used in citrus fruits and of many produce. Both of dimethoate and its metabolite possess high toxicity and carcinogens. The demand of developing a stable and sensitive scheme is, thus urgently needed.
The detection scheme was based on the basis of cobalt phthalocyanine (CoPC) can catalyze the oxidation of electrode. A suitable quantify of CoPC modified ink was pipetted onto a polished GC electrode and air-dried. An operational potential of +100mV (vs. Ag/AgCl) was used to detect dimethoate. In the optimum condition, the linearity is up to 2.4 M with correlation coefficient of 0.9997 and the detection limit of dimethoate is 20.93nM (S/N=3). Its relative standard deviation is 1.02% at a series of twenty repetitive measurements and the response time is 2.1 seconds. The scheme is very precise with low interference advantage. Other advantage includes stable and sensitive characteristics. These sensitive schemes meet the requirement of the residue of dimethoate of US EPA.
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