Preparation And Properties Of Nanofibrous Membrane Fluorescent Sensors

Fluorescent probes have been widely used to detect heavy metal ions and pH values in water environment.They are mostly in the form of powder in the market,which is difficult to recycle and reuse,and easy to cause pollution to the environment.The fluorescence probe was combined with the electrospun nanofiberous membrane?NFM?to improve the detection sensitivity of the fluorescence probe,which was also easy to be reused and recycled.Therefore,the following studies were conducted:1.A novel fluorescent probe,coumarin derivative?CMd?,was synthesized by using2-Hydroxy-4-methylbenzaldehyde and 4-Hydroxy-6-methyl-2-pyrone.The fluorescence sensor of PA6/CMd NFM was made by PA6 with CMd Electrostatic spinning.IR testes demonstrated the stability of CMd in PA6 NFM.The sensing limit of PA6/CMd NFM on Cu²⁺was 1×10^-7 M.Good fluorescence can be maintained in aqueous solutions with different pH values.After repeated use for 5 cycles,the quenching efficiency of the PA6/CMd NFM decreases slightly.2.EVOH-PABA-Py NFMs were prepared by PABA,Py-CHO and EVOH NFM.XPS and UV spectra confirme the effective graft of PABA and Py-CHO on the NFM surface.When the concentration of Cu²⁺reaches 5×10^-3 M,the quenching efficiency was91.7%.The sensing limit of Cu²⁺by EVOH-PABA-Py NFM was 1×10^-99 M.After 10cycles,the quenching efficiency of the nanofiber membrane remaines relatively stable.3.A novel fluorescence probe,a derivative of rhodamine B?RMB_N?,was synthesized by using rhodamine B and diethylenetriamine.IR and XPS tests proved that RMB_N was successfully grafted onto the PAN NFM.The PAN-RMB_N NFM had double fluorescence response to strong acid solution and Fe³⁺,and had obvious double peaks at470 and 600 nm,showing orange-red light.The sensing limit of PAN-RMB_N NFM on Fe³⁺was 5×10^-3 M.In alkali solution with pH=12,PAN-RMB_N NFM could recover initial value,which had the advantages of sensitive reaction and recycling.In conclusion,the fast,stable and reproducible performance of the three NFM fluorescence sensors provides new insights for research and development.Figure 46;Table 6;Reference 67...