Preparation And Performance Study Of Fluorescent Probes Based On Carbon Dots

Carbon dots(CDs)process unique optical properties,different detection methods were designed and constructed by different quenching mechanisms,Rayleigh resonance scattering(RRS)and the unique optical properties of analytes.The specific work of this paper is listed as follows:1.Citric acid,thiourea and hydrogen peroxide were utilized to prepare CDs which process purple fluorescence via one-step hydrothermal method.When Fe3+ was added,the fluorescence of CDs can be quenched by Fe3+ through static quenching.Then,glutathione(GSH)was added in,GSH and Fe3+ had stronger binding force,Fe3+ was removed from the surface of CDs,so the fluorescence of CDs is restored.Thus,the detection of Fe3+ and GSH was realized.2.Citric acid and diethylenetriamine were used to prepare CDs which process blue fluorescence.The fluorescence of CDs at 420 nm was quenched through inner filter effect(IFE)while the fluorescence of curcumin at 525 nm was enhanced after adding curcumin.After adding Fe3+ into the system of CDs-curcumin,curcumin complexed with Fe3+ leading to the quenching of the fluorescence of curcumin at 525 nm,the fluorescence of CDs at 420 nm was recovered.Thus,the ratiometric detection of curcumin and Fe3+ was realized.The CDs-curcumin system was successfully applied for H1299 cell imaging and PVDF membrane fouling research of iron flocculants in wastewater treatment.3.The fluorescence of CDs which were prepared from citric acid and diethylenetriamine at 425 nm was quenched by ARS through IFE,while the Resonance Rayleigh Scattering(RRS)at 350 nm was enhanced after adding ARS.The ratiometric detection of ARS was realized.After adding Pb2+ into the system of CDs-ARS,ARS can complex with Pb2+ in 3:2,leading to the enlargement of molecular volume and the increase of the RRS at 350 nm.The process of IFE was weakened,the fluorescence of CDs at 425 nm was recovered.Because the enhancement of RRS is much greater than the recovery of CDs fluorescence,the ratiometric detection of Pb2+ can be realized.4.Utilizing intensive absorption of tetraphenylporphyrin at 413 nm and the fluorescence of ciprofloxacin,Tris-CDs,the fluorescence depression at 413 nm was formed,which is realized by IFE mechanism.After adding acid solution with different pH,the UV-vis spectra of tetraphenylporphyrin changed obviously and the position of strong absorption moved from 413 nm to 438 nm,so the position of IFE process also shifted,fluorescence depression appeared in the new position and the original depression was restored,thus achieving the purpose of ratiometric detection of pH.