Portable Detection Of Heavy Metals And Acidic And Alkaline Gases Based On AIEgens Functional Hydrogels

Nowadays,environmental pollution brought by heavy metals such as lead,cadmium and mercury could cause lesions in the body’s secretion system,which can cause various diseases such as cardiovascular diseases,thus causing great harm to the human body.And the large number of toxic emissions can also pose a danger to people’s living environment.The implementation of real-time monitoring of these environmental pollutants can effectively prevent these problems.There was a wide range of instruments used for environmental monitoring,and the more common devices used were liquid chromatograph,gas chromatograph,atomic absorption spectrometer,etc.Although these instruments can provide more accurate and authoritative data,they had the disadvantages of large size,cumbersome operation,and high cost.Therefore,this paper designs two fluorescent hydrogel sensors with aggregation-induced luminescence effect（AIE）to achieved real-time monitoring of mercury ions and acidic and alkaline gases in the environment.（1）In this paper,a mercury（Hg）-responsive fluorescent hydrogel sensor DTPEP-SA was prepared using a derivative（DTPEP）synthesized from phenanthroline and tetraphenylethylene（TPE）and sodium alginate hydrogel（SA）as the sensing matrix using a physical embedding method.The structural properties of the hydrogels were analyzed based on the characterization of scanning electron microscopy（SEM）,Fourier infrared（FTIR）,Zate potential,and fluorescence properties.The DTPEP-SA sensor produces fluorescence quenching upon contact with mercury in detection applications,and maintains high selectivity for mercury ions despite interference from multiple metal ions in water and solid samples.This enables the visual detection of mercury in aqueous and solid samples.At the same time,a dopamine（PDA）derivative PDA-PAAm viscous gel was used as a surface coating material to successfully coat a hydrogel sensor on a single carrier,thus completing the fabrication of a simple and rapid field contaminant detection device.For the visualization of DTPEP-SA,RGB values of the hydrogel sensor images taken by cell phones were analyzed and output by the grayscale-based Android software"Detect"to quantify Hg²⁺.The detection time is within 15 min,the detection limit is as low as 0.06μM,and the grayscale value is linearly correlated with the Hg²⁺concentration in the range of（0～2μM）.（2）A p H-sensitive fluorescent probe（In TPAPy）based on benzindolium iodide and triphenylamine was prepared,and real-time monitoring of acidic and alkaline gases was achieved by a composite hydrogel In TPAPy-SA/HA generated after attachment to sodium alginate/sodium hyaluronate（SA/HA）.The structure and physicochemical properties of the In TPAPy-SA/HA sensor were analyzed using scanning electron microscopy,FTIR,specific surface area analysis,and fluorescence performance characterization.In practice,the In TPAPy-SA/HA sensor produces different color responses for the online detection of acid and alkaline gases with high selectivity.The MATLAB software is used to analyze the sensitive area（ROI）of the In TPAPy-SA/HA sensor picture,and the color phase（H-value）and saturation（S-value）of the output can be quantified for acid and alkaline gas content.The color response can be produced within 30 s for the detection of HCl and 10-30 s for ammonia.the LODs were calculated to be 0.13 ppb and 1.0 ppb for HCl and ammonia,respectively.This flexible visual and fast sensing system has great potential not only for the detection of mercury in water and solid samples,but also for the visual and fast detection of acidic and alkaline gases.In this article,two new fluorescent probes were synthesized based on the AIE effect and have good photosensing effects on the targeted contaminants.At the same time,two portable hydrogel sensors were successfully prepared by combining these two fluorescent probes with sodium alginate composite hydrogel using the physicochemical encapsulation method,which successfully realized the real-time monitoring of the targeted contaminants.The two hydrogel sensors are shown to have potential practical applications.