Research On The Preparation And Application Of Several Fluorescence Sensors Based On Organic And Organic-inorganic Hybrid Materials

With the development of society and the advancement of science and technology,the problem of environmental pollution has become increasingly prominent.It is extremely important to effectively detect and monitor environmental pollutants such as metal ions and anions.Trace quantification of metal ion and anion concentrations present higher requirements for the sensitivity and reliability of analytical detection.Fluorescence sensors have been widely used in the detection of metal ions and anions in recent years due to their advantages of simple operation,low cost,short response time and high sensitivity.In this paper,we designed and synthesized a series of organic and organic-inorganic hybrid materials to achieve high selectivity and sensitivity detection of metal ions(Fe3+,Al3+ and Hg2+)and anions(S2-).The main research contents are as follows:The imidazole-pyrene-based derivative MBT and MBMT,the thiazoline-pyrene-based derivative BPT and BPMT were synthesized by using pyrene as the fluorescent reporter group,and the relationship between receptor group and sensing performance of metal ions was studied.The results showed that,(1)the introduction of carbonyl functional groups into the receptor group could improve the specific recognition performance of the detection system for metal ions:MBT and BPT containing carbonyl could selectively identify specific metal ions,while MBMT and BPMT without carbonyl groups had fluorescence response to a variety of metal ions,but did not have selectivity for specific metal ions;(2)changing the heterocyclic ring(imidazole and thiazoline)in the recognition group could adjust the selectivity of the fluorescence sensor to metal ions:MBT could selective recognition of Fe3+,only addition of Fe3+,the fluorescence intensities at 387 nm and 410 nm wrere quenched;and BPT could selectively recognize Cu2+.2、The ratiometric and fluorescent sensor DBT was synthesized,by using 2,2’-dipicolylamine and l-(bromoacetyl)-pyrene,which showed high selectivity and sensitivity toward Al3+.DBT exhibited very weak fluorescence because of the photo-induced electron transfer process(PET).In the presence of Al3+,the emission of DBT at 451 nm enhanced owing to the coordination between Coordinating atom(O and N)of DBT and Al3+which hindered the PET,the fluorescence color of solution from lyons to brilliant blue.The absorption intensity ratio(A360 nm/A342 nm)and fluorescence intensity at 451 nm over the concentration of Al3+ displayed linear relationships in the range of(0.2-4.0)×10-5 M and(0.2-6.0)×10-5 M,and the detection limits of Al3+ were 0.19and 0.10 μM,respectively.3、Two organic fluorescent molecules P1 and M were synthesized,and then P1 and M were covalently grafted into the mesoporous of SBA-15 to obtain two fluorescent nanomaterials,SBA-15-P1 and SBA-15-M,and their sensing performances for metal ions were investigated.SBA-15-M was responsive to Cu2+,Hg2+ and Co2+,but did not have selectivity for specific metal ions,SBA-15-P1 had high selectivity and sensitivity for Hg2+.The fluorescence intensity over the concentration of Hg2+ displayed linear relationships in the range of(0.2-10.0)×10-5 M,and the detection limit of Hg2+ was 0.10 μM.It was proved that the extra coordination atoms into the recognition group could improve the specific recognition performance of the detection system for metal ions.4、Simple mixing of SBA-15-P1 and SBA-15-M with Hg2+ yielded two hybrid materials SBA-15-P1/Hg2+ and SBA-15-M/Hg2+,and the anions recognition performance was studied in H2O solution.The results showed that,only addition of S2-,the fluorescence of SBA-15-M/Hg2+ recovered,but SBA-15-P1/Hg2+ did not have selectivity for specific anions;SBA-15-M/Hg2+ detected S2-from interfering ions,the pH range was 6-12.