Preparation Of Reactive Fluorescent Probe With Double Acting Sites Employing Carbazole As Fluorescent Units And Application In Detection Of Sulfite

Since the beginning of the 21st century,fluorescent probe has been widely used in the detection of anions,cations and small molecules generated in organisms due to its advantages of high selectivity,high sensitivity,rapid response,detection visualization,convenient operation,strong practicability and easy popularity.The types of fluorescent probes can be divided into reactive fluorescent probes and complex fluorescent probes according to the binding mode of probe molecule and target.Among them,reactive fluorescent probe is designed according to the specific structure of the substance to be detected,and it can identify with the target substance through a specific and irreversible chemical reaction,which has more excellent sensitivity and selective recognition ability.In this paper,four reactive fluorescent probes were designed and synthesized using carbazole,5-chlorobenzothiazole salt and indole salt derivative as probe structural units,and were applied to the detection of bisulfite ions.The details are as follows:1.carbazole as electron donor,5-chlorobenzene and thiazole salt as electron acceptor,both by thiophene or benzene connection in order to enhance the intensity of conjugate of the probe,to produce a strong polarization effect of unsaturated C=C double bond structure of HSO₃^-ion recognition site.At the same time,to enhance the solubility and increase of probe probe molecular recognition HSO₃^-reaction sites,using1,6-dibromo hexane for connection,design and synthesis of the two has the double recognition site of double D-π-A chain of fluorescent probe.As we imagined,probe WTA and WTB of HSO₃^-ion has good response,and presents the high selectivity and sensitivity,the detection limit of bisulfite 900 nm and 2.8μM respectively.At the same time,the above two probe used in the sugar and wine HSO₃^-ion detection and achieve success.2.Two kinds of probes,DAB and DAC,with carbazole derivatives as energy donors and indole salt derivatives as energy receptors,were designed and synthesized.DAB and DAC were double recognition site reactive fluorescent probes based on Michael addition.When HSO₃^-ion and unsaturated C=C double bond after addition reaction,fluorescent probe molecules within the ICT process is blocked,probe molecule conjugate strength weak,trigger probe the change of the uv-vis spectra and fluorescence emission spectrum,so as to realize HSO₃^-ion of visual detection.The limits of detection for bisulfite were 1.4μM and 700 n M respectively.At the same time,the DAB and DAC successfully applied in sugar and in red wine HSO₃^-ion detection.