Preparation And Properties Of Pentachloronitrobenzene Molecularly Imprinted Biomimetic Receptorand Fluorescence Sensor

Pentachloronitrobenzene（PCNB）is one of the organochlorine pesticides and is widely used in field disinfection and seed sterilization.Pentachloronitrobenzene has been banned and restricted by various countries due to the huge harm of pesticide residues.At present,the national standard method of pentachloronitrobenzene is chromatography,which has the advantages of accuracy and sensitivity,but there are determinations of high cost,complicated operation and difficult pretreatment.In order to make up for the problem of poor separation of pentachloronitrobenzene and other pesticides in the pretreatment of chromatographic analysis in the detection of pesticide residues,this study based on molecular imprinting technology and determined the PCNB by precipitation polymerization Template molecule,α-methacrylic acid（MAA）,acrylamide（AM）,4-vinylpyridine（4-VP）as functional monomers,ethylene glycol dimethacrylate（EGDMA）as crosslinking agent,2.2-Azobisisobutyronitrile（AIBN）is used as the initiator,and acetonitrile is used as the porogen to synthesize molecularly imprinted bionic receptor materials.Based on the different structure of biomimetic receptor carrier,carrier-free biomimetic adsorbent material（Carrier-free@MIP）and biomimetic adsorbent material with silica nanoparticles as carrier（COOH-SiO₂@MIP）were prepared.The adsorption capacity and selectivity were characterized.The results showed that the material had good adsorption performance.The maximum apparent adsorption capacities of Carrier-free@MIP and COOH-SiO₂@MIP were 60.28 mg/g and 104.49 mg/g,respectively.Sexual adsorption capacity,non-specific adsorption and specific adsorption coexist.The biomimetic receptor can reach adsorption saturation in 40-50 min,and has good selectivity to pentachloronitrobenzene and its analogs（HCH,PCD）.After repeated use 5 times,the material can achieve a loss of adsorption capacity below 25%.Based on the current detection of pesticide residues mainly by chromatography,lack of rapid,efficient and cheap detection methods in the field environment,this paper uses fluorescent molecular imprinting technology to determine the alpha-methacrylic acid（MAA）,acrylamide（AM）,4-Vinylpyridine（4-VP）is a functional monomer,divinylbenzene（DVB）is a crosslinking agent,2,2-azobisisobutyronitrile（AIBN）is an initiator,and acetonitrile is a porogen,choose FITC-APTES is used as a signal unit to synthesize a fluorescent molecularly imprinted bionic sensor（FITC-APTES@SiO₂@MIP）on the surface of SiO₂.The fluorescence stability,fluorescence signal response time,selectivity and other indicators were characterized.The results show that the sensor has good fluorescence stability,the fluorescence intensity is stable at about 90%in 20 days,and the response speed to pentachloronitrobenzene is fast,and 25%of the signal response value can be achieved in 30 minutes.The sensor has good selectivity for pentachloronitrobenzene and its analogues,and is not interfered in the mixed solution.The sensor has good selectivity to pentachloronitrobenzene and its analogues,and is basically undisturbed in the mixed solution.