ساخت حسگر فلورسانس بر پايه پليمر قالب مولكولي روي نقاط كوانتومي كربن جهت تشخيص تانيك اسيد

چكيده انگليسي :

Fabrication of fluorescence sensor based on molecularly imprinted polymer on carbon quantum dots to detect tannic acid Shabnam Sistani sistani 97@ag iut ac ir February 16 2021 Department of Food Science and Technology Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Hajar Shekarchizadeh Shekarchizadeh@iut ac irAbstractThe aim of this study was to fabricate a fluorescence sensor based on carbon quantum dots and molecularlyimprinted polymer to detect tannic acid Carbon quantum dots were synthesized using hydrothermal method andcitric acid precursor as carbon source and polyethylene amine as nitrogen source The presence of amine groups ledto the synthesis of carbon quantum dots with high quantum yield 24 Transmission electron microscopy TEM images showed the quasi spherical morphology of carbon quantum dots with an average size of 4 9 nm XRDresults indicated the amorphous structure of these nanoparticles To increase the selectivity of the synthesizedsensor to tannic acid the molecularly imprinted polymer technique was used in which a layer of molecularlyimprinted polymer was synthesized by surface printing on carbon quantum dots and nanocomposite MIPs CDswere obtained In order to evaluate the performance of molecularly imprinted polymer control nanocompositeNIPs CDs were synthesized similar to the steps of molecularly imprinted polymer synthesis without addingtemplate molecule Field emission scanning electron microscopy FESEM images of MIPs CDs and NIPs CDsnanocomposites showed that both nanocomposites have a spherical structure and the same size To investigate theoptical properties the emission and absorption spectra of carbon quantum dots and nanocomposite CDs MIPs wereinvestigated Fourier transform infrared FTIR spectroscopy was performed to investigate the functional groupsand to confirm the synthesis of carbon quantum dots and molecularly imprinted polymer Parameters affecting thesensor response such as pH effect time effect and nanocomposite amount were optimized The effect of 12interfering species on sensor response was also investigated The results showed that the sensor has good selectivityto tannic acid in the presence of interfering factors Experiments have shown that the presence of tannic acidreduces the fluorescence intensity of the sensor which is due to the transfer of electrons from the tannic acid to thecarbon quantum dot Under optimal conditions the linear range of the sensor response was obtained at aconcentration of 1 200 nmol L 1 tannic acid and a detection limit of 0 6 nmol L 1 Finally the sensor was used tomeasure tannic acid in grape juice green tea and black tea samples using the recovery method Recovery valuesbetween 97 4 103 6 and RSD less than 3 8 were obtained indicating the appropriateness of the proposedmethod for the detection of tannic acid in real samples In general fluorescence sensors were synthesized with highaccuracy and sensitivity to detect tannic acid Also comparing the results of the proposed method with other studiesreported to measure tannic acid indicates that this method has a better linear range and limit of detection whichindicates its good potential for analytical applications in complex food samples Key Words Fluorescence sensor Carbon quantum dots Molecularly imprinted polymer Hydrothermal Tannicacid

سيستاني، شبنم

ساخت حسگر فلورسانس بر پايه پليمر قالب مولكولي روي نقاط كوانتومي كربن جهت تشخيص تانيك اسيد

حسگر فلورسانس , نقاط كوانتومي كربن , پليمر قالب مولكولي , هيدروترمال , تانيك اسيد