screening of total organophosphate pesticides in agricultural products with a ce

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1、ScreeningofTotalOrganophosphatePesticidesinAgriculturalProductswithaCeABSTRACTOrganophosphatesbelongtothemostimportantpesticidesusedinagriculturalpracticeinationsarequitefeasibleethods,thereisalackofefficientscreeningmethods,odities.Thisstudypresentstheconstructionofarapidandsensitivecellularbiosens

2、ortestbasedonthemeasurementofchangesofthecellmembranepotentialofimmobilizedcells,accordingtotheal(neuroblastoma)orplantcells(tobaccoprotoplasts).Thesensorixtureoftato,orange).Thepesticidesinthesamplesinhibitedtheactivityofcellmembrane-boundacetylcholinesterase(AChE),thuscausingameasurablemembranedep

3、olarizationinthepresenceofachetylcholine(Ach).Basedontheobservedpatternsofresponse,onstratethatthesensorcanbeusedforthequalitativeand,insomeconcentrations,quantitativedetectionoforganophosphatesindifferentsubstratesitofdetectionatleastequaltotheofficialLimitofDetection(LOQ).Theassayisrapidinatapetit

4、ivecost.ThesensitivityofthebiosensorcanbefurtherincreasedeitherbyincorporatingmoreAChE-bearingcellspertestreactionunitorbyusingcellsengineeredorepotentAChEisoforms.Standardizationofculturedcellparameters,suchasageofthecellsandsubculturehistorypriortocellimmobilization,binedechanismofactionistheirrev

5、ersibleinhibitionofacetylcholinesterase(AchE),akeyenzymeintherecyclingoftheneurotransmitteracetylcholine(Ach)[2].Organophosphatesphosphorylatetheserinehydroxylgroupatthesiteofactionofacetylcholine.Theybindirreversibly,deactivatingtheesterase,resultinginaccumulationofacetylcholineattheendplate.Decrea

6、seinplasmacholinesteraseresultsinadecreaseofcholinesteraseactivityinthecentral,parasympathetic,andsympatheticnervoussystems.Accumulationofacetylcholineattheneuromuscularjunctioncausespersistentdepolarizationofskeletalmuscle,issioninthecentralnervoussystemisdisrupted[3].Long-termexposuretoorganophosp

7、hateshasbeenassociatedemoryandconcentrationandotherneurophysiologicalabnormalities[4-6].Theconventionalanalysisofpesticideresiduesinfoodmoditiesisalaborintensiveprocedure,sinceitisnecessarytocoveraica