Construction Of Ratiometric Fluorescent Probes And Their Application In Drug Analysis

Fluorescence sensor has the advantages of high sensitivity,low detection limit,good selectivity,wide linear range and so on.Thus,it has attracted great attention in the scientific community.Among them,the ratiometric fluorescence sensors realize the analysis of the target analyte by recording the ratio of the fluorescence intensities at two different wavelengths.They have aroused the widespread interest of scientific researchers in the analysis of complex samples.Compared with a single signal fluorescent probe,the ratio fluorescent probe has an important feature of the avoidance of potential interference from background fluorescence,thus the sensitivity and accuracy can be improved.In recent years,with the continuous development of nanoscience and technology,the ratiometric fluorescent nanoprobe comes into being.It possesses the characteristics of ratio fluorescent probe as well as the advantages of nanomaterials.Therefore,it has drawn great attention in the field of sensing.In this research,three types of fluorescence sensors have been constructed based on different ratiometric fluorescent probes for the analysis of the drugs including alendronate sodium(ALDS)and bleomycin(BLM).The specific research content is as follows:(1)A ratiometric fluorescence sensing platform for Ce⁴⁺and ALDS has been developed based on graphene quantum dots(GQDs).In the absence of hydrogen peroxide(H₂O₂),Ce⁴⁺can oxidize o-phenylenediamine(OPD)to produce2,3-diaminophenolazine(DAP)showing orange fluorescence.The fluorescence of GQDs can be quenched by DAP through the internal filtering effect(IFE)between DAP and GQDs.The presence of ALDS reacts with Ce⁴⁺,inhibiting the oxidation of OPD by Ce⁴⁺.Thus,fluorescence of DAP weakened and the fluorescence of GQDs recovered.Based on the above principles,the sequential detection of Ce⁴⁺and ALDS is realized,and the detection limits of Ce⁴⁺and ALDS are as low as 1.0?M and 33n M,respectively.In addition,this method has been successfully applied to the detection of Ce⁴⁺in actual water samples and ALDS in human urine,with satisfactory recovery results.(2)A ratiometric fluorescence sensing platform for ALDS has been constructed based on Ce⁴⁺-OPD-AA system.Ce⁴⁺oxidizes ascorbic acid(AA)to produce dehydroascorbic acid(DHAA),which then reacts with OPD to produce3-(dihydroxyethyl)furan[3,4-b]quinoxolin-1-one(DFQ)showing blue fluorescence.As an oxidant mimic enzyme,Ce⁴⁺can also oxidize OPD to generate DAP which produce orange fluorescence.ALDS can inhibit the oxidation of OPD by Ce⁴⁺.The fluorescence of DAP can be quenched.Thus,the ratiometric fluorescence sensing platform of ALDS was constructed.The linear response range was 0.1?M?10?M and 10?M?70?M,and the detection limit was as low as 30 n M.In addition,the sensing platform has successfully achieved the detection of ALDS content in drug tablets and human serum.(3)A ratiometric fluorescence sensing platform for BLM has been constructed based on Cu²⁺-triggered cascade reaction initiated.Cu²⁺oxidizes AA to generate DHAA,which then reacts with OPD to generate blue fluorescent DFQ.Cu²⁺can also oxidize OPD to produce DAP which emits orange fluorescence and the generated Cu NPs can catalytic the oxidation of OPD by Cu²⁺.BLM can interact with Cu²⁺,inhibiting the formation of DAP.As a result,the sensitive detection of BLM was successfully realized,and the detection limit of BLM was 0.05 n M.In addition,this method has been applied to the detection of BLM in human serum with satisfactory results.