Design And Development Of Reactive Fluorescence Probe Based On O-phenylenediamine

Cerium(Ce)is widely used in industry as polishing powder,phosphor,magnet,catalyst and ceramic colorant.In nature,cerium usually exists in trivalent form,but Ce(Ⅳ)is easier to extract and separate from cerium carbonate.Therefore,in the process of mineral extraction and metallurgy,Ce(Ⅲ)is often converted into Ce(Ⅳ)in the post-treatment stage to facilitate the selective extraction of Ce ions.It is harmful to the environment.Therefore,the detection of Ce(Ⅳ)is very necessary.Small molecule fluorescent probes have the advantages of high sensitivity,high selectivity and short response time.They are powerful tools for detecting important analytes in environment and organism.Based on this,a fluorescent probe for the detection of metal Ce(Ⅳ)ion was designed based on some organic reactions involving o-phenylenediamine.At the same time,considering the risk of carcinogenicity and teratogenicity of o-phenylenediamine,a fluorescent probe for the detection of o-phenylenediamine was developed.The specific research contents are as follows:1.Ce(Ⅳ)ion fluorescent probe based on the oxidation of o-phenylenediamineThe selective recognition of Ce(Ⅳ)by o-phenylenediamine was studied.The mechanism is that the oxidation of Ce(Ⅳ)can promote the intermolecular oxidative cyclization of o-phenylenediamine to produce a strong yellow fluorescence product2,3-diaminophenazine,with fluorescence enhancement of more than 150 times.From the job’s plot curve,it can be concluded that the reaction between o-phenylenediamine and Ce(Ⅳ)ion is carried out in the molar ratio of 1: 2.The linear range of the optimized fluorescent probe was 0.4-4 μmol/L and 5-36 μmol/L,and the detection limit was 26 nmol/L when the signal-to-noise ratio(S/N)was 3.The practicability of the probe in the determination of Ce(Ⅳ)in Ganjiang River water,tap water,rain water and Ganzhou red soil was further demonstrated.When the concentration of silver ion and copper ion is high,the reaction of OPD can also be promoted to produce 2,3-diaminophenazine.This may bring potential interference to the detection.2.Ce(Ⅳ)ion fluorescence sensor based on the cyclization of naphthol with o-phenylenediamineIn order to solve the above-mentioned interference factors,we designed to use the unique single electron oxidation property of Ce(Ⅳ)ion to oxidize β-naphthol to obtain 1,2-naphthoquinone,and then condense with o-phenylenediamine to form fluorescent benzo [a] phenazine.Due to the high selectivity of single electron oxidation of β-naphthol by Ce(Ⅳ),the potential interference of silver and copper ions is avoided.The linear range of the probe is 8-160 μmol/m,and the detection limit is 1.23 μmol/L when the signal-to-noise ratio(S/N)is 3.The detection system has good selectivity and the fluorescence signal is enhanced more than 200 times.It has been successfully applied to the detection of practical samples.3.Fluorescent probe of o-phenylenediamine based on organic tandem cyclizationA fluorescent probe based on nucleophilic cyclization reaction was developed for the determination of o-phenylenediamine in real samples.Quinoxaline derivatives were synthesized by nucleophilic cyclization aromatization of 2-bromo-1-(naphthalene-2-yl)ethanone(BNEO)with o-phenylenediamine at room temperature without any catalyst.According to the organic reaction principle,the fluorescence enhancement of bneo can reach 110 times after adding o-phenylenediamine.The practicability of o-phenylenediamine detection was successfully verified in Ganjiang River water,Ganzhou rain water,tap water and red soil samples.