Preparation And Detection Performance Of Zn(Ⅱ)、 Al(Ⅲ)、 ClO~- And CORM-3 Fluorescent Probes

Zinc ion(Zn²⁺),aluminum ion(Al³⁺),hypochlorous acid（HClO/ClO^-）and tricarbonyl chloride（glycinyl）ruthenium（CORM-3）are closely related to human health or environmental protection.For example,Zn²⁺is an active component of biological growth and reproduction,and too low a level of Zn²⁺can cause serious disease in humans.Excessive Zn²⁺in water can lead to environmental pollution and phytotoxic effects.Excessive levels of Al³⁺in the human body can damage the central nervous system,and the concentration of Al³⁺in drinking water should be limited to7.41μM or less.The dose of Al³⁺in water can also affect plant growth and reduce crop quality.Low doses of HClO can kill bacteria in humans,but excessive amounts of HClO in the body can cause metabolic disorders.As the main component of disinfectants and bleach,ClO^-is widely used in daily life.A large number and frequent use of ClO^-will cause pollution to the water environment and harm the health of water organisms.CORM-3 is a water-soluble carbon monoxide（CO）-releasing molecule that has anti-inflammatory and cardioprotective properties and has shown promising therapeutic effects on tissue transplantation,myocardial infarction and rheumatoid arthritis.Therefore,the detection and analysis of these substances is of great significance.Fluorescence probe analysis method has the advantages of low cost,simple sample preparation,rapid detection,applicability and sensitivity,and can be used for in vivo/in vitro bioimaging of samples.However,some reported fluorescent probes still have many shortcomings,such as small Stokes shift（<100 nm）,low quantum yield（<0.25）,poor optical stability,emission wavelength in the short wavelength region,long detection time,low detection range.In this paper,four kinds of fluorescent probes based on dicyanoisophorone,2-（2-hydroxyphenyl）benzothiazole（HBT）and coumarin fluorophore with excellent luminescence properties were successfully prepared to achieve the detection of Zn²⁺,Al³⁺,ClO^-and CORM-3.（1）Probe A was synthesized from dicyanoisophorone and o-phenylenediamine by convenient Schiff base reaction.The probe was combined with Zn²⁺in CH3CN/HEPES buffer solution（v/v,1/1,pH=7.4,10 m M）to emit significant near-infrared fluorescence（maximum emission wavelength 660 nm）.The fluorescence intensity of probe A showed a good linear relationship with the concentration of Zn²⁺in the range of 0～10μM,and the detection limit was as low as 4.8 n M,indicating that the probe had a high sensitivity to Zn²⁺.The probe has the advantages of fast response time（less than 30 s）to Zn²⁺,large Stoker shift（179 nm）,wide pH application range（6.0～8.0）,etc.High recovery rate was obtained in actual water samples,and clear fluorescence images were obtained in A549 living cells.（2）Probe B was synthesized by Schiff base reaction from flake halloysite,coumarin fluorophore and methylhydrazine 2-furanoate.The probe has specific response to Al3+in pure water,and can realize the integrated operation of analysis and separation of Al³⁺in water.The presence of Al³⁺makes the fluorescence of the probe change from colorless to blue.Probe B has high sensitivity to Al³⁺,and the Al³⁺concentration shows a good linear relationship with the fluorescence signal of the probe in the range of 0～8μM.The quantitative detection of Al³⁺can be realized,and the detection limit is 0.55μM.Probe B can respond to Al³⁺within 10 min and has a wide pH application range（4.0～8.0）.In addition,probe B was also applied to the detection of actual water samples（tap water,pond water and drinking water）,and obtained a good recovery rate.（3）A highly selective probe C for the detection of ClO^-was synthesized by Schiff base reaction using halloysite,coumarin fluorophore and 1,1-dimethylhydrazine hydrochloride as raw materials.Probe C exhibits light yellow fluorescence in water,but the presence of ClO^-can change the light yellow fluorescence into blue fluorescence.When other common anions were added,the fluorescence of the probe was negligible,indicating the specificity of the probe for the detection of ClO^-.The detection limit of the probe for ClO^-was 110.8μM,and the fluorescence signal of the probe had a good linear relationship with the concentration of ClO^-in the concentration range of 0～477μM.（4）Using 2-（2-hydroxy-phenyl）benzothiazole（HBT）derivatives as optical signal units and 4-nitrobenzene as reaction units,fluorescence probe D was prepared by condensation reaction.In PBS/DMSO buffer solution（1/1,v/v,pH 7.4,10 m M）,the probe showed a specific response to CORM-3 and gave off significant near-infrared fluorescence（maximum emission wavelength 720 nm）after reacting with CORM-3 in the absence of heavy metal ions.The linear relationship between probe D and CORM-3 concentration（in the range of 0～175μM）was good,and the detection limit was as low as 0.11μM,indicating that the probe had high sensitivity to CORM-3.The probe’s response to CORM-3 was stable within 30 min,with a large Stoker shift（195 nm）and pH range of 6.0～12.0.In addition,the probe has a red-edge effect,and the excitation wavelength and emission wavelength can be adjusted reasonably according to the test requirements to avoid interference signals.More importantly,it has been successfully used for high-resolution fluorescence imaging detection of CORM-3 in living cells and zebrafish.