Studies On Rapid Detection Of Orgnaophosphorus And Carbamate Pesticides By Enzyme-biosensor

Recent years, the issue of pesticide residues in food have caused more attention over the world. Some virulent kinds of orgnaophosphorus and carbamate pesticides such as Tamaron, DNTP, Folimat and Carbofuran are still used to vegetables and fruits in some regions although these have forbidden by the government, the toxicosis incidents of human and animal resulted from taking food which contains high level of pesticide residues are happened usually, which are harming to food security. Therefore, research and development a convenient, rapid, sensitive and practical technique to adapt to the produce and sale status of agriculture product for inspection pesticide residues are urgent demands in our country today.At present, detection of pesticide residues by enzyme-biosensor is a hot spot. High activated enzyme of immobilized enzyme membrane is key technique which ensures good sensitivity of biosensor. This study applied Konjac Glucomannan as carrier immobilized phytoesterase firstly. Then prepared biosensor by this neotype immobilized enzyme membrane, which can analyse quantitatively pesticide residues in food rapidly.The results are as follows:(1) The method of purify KGM is easy to operate and the purity reached 89.61%. The major agent is Alcohol, which toxicity is lower, pollution is smaller and easy to recovery. The production can be produced membrane to immobilization phytoesterase.(2) Konjac Glucomannan was deacetyl for membranes by Na₂CO₃. The membranes made from denatured KGM showed better water resistance capability, uniformity and scrub resistance than that from undenatured KGM.(3) This study applied KGM as carrier immobilized phytoesterase firstly. The optimized parameters of produce enzyme membrane was as follows: optimal pH9.0, and the quantity of bovine serum albumin(BSA) is 20μL, drying temperature and time is 25℃and 7h respectively. The enzyme activity recoveries ratio was reached 50%.(4) The method of rapid detection pesticide residues using enzyme-biosensor has been established. The operation process is: put the biosensor into 5mL sample solution, react for 20min, then add 0.5mL of a-Naphthyl acetate and detect pH immediately, and then react at 40℃for 20min, detect pH at room temperature. Meanwhile reference electrode is to contrast.(5) The sensitivities tests were showed that the enzyme-biosensor was sensitive to most of the organophosphate pesticides and all of the carbamate pesticides which we have studied. The LDCs are lower than their MRLs except monocrotophos. So, we can conclude that the enzyme-biosensor can fulfill the detection demands of organophosphate and carbamate pesticides which we have studied.