Construction Of Paper-Based Smart Optical Devices For Formaldehyde Detection

Formaldehyde(FA)is one of the simplest carbonyl compounds with high reactivity and cytotoxicity.Studies have shown that excessive FA can easily lead to a series of diseases such as Alzheimer’s disease,leukemia,Fanconi anemia,and cancer.At the same time,FA is also a common environmental pollutant,ubiquitous in furniture,food and clothing.Therefore,the problem of FA detection has always been the focus of people’s high attention,and the development of highly sensitive,simple,fast and accurate FA monitoring technology is of great significance to human health and environmental hazards.In recent years,paper-based detection technology based on fluorescence has gradually become an important means for real-time and accurate detection of FA in environmental monitoring because it can quickly identify the presence of analytes by observing color changes with simple instruments.However,the FA fluorescent paper-based devices reported so far generally have defects such as difficult preparation,cumbersome operation and high detection cost.Therefore,the development of a simple,efficient,cost-effective and time-saving new FA analysis technology is essential for on-site detection and its quantitative research.In this study,in view of the research status of the difficulty in constructing FA fluorescent paper-based devices,ratiometric FA fluorescent nanoprobes with excellent performance were designed and synthesized by co-chemical precipitation,and the application of the obtained nanoprobe in visualizing and monitoring FA on paper-based devices was systematically studied,and a portable optical sensing system based on smartphones was designed by combining efficient image analysis technology to realize the on-site quantitative detection of FA.The main research contents are as follows:1.In this chapter,four ratiometric FA fluorescent nanoprobes(Nano-FAPs)were successfully designed and synthesized by studying the compound ratio relationship between the responding fluorophore and the reference fluorophore.Further analysis of the test and characterization results of its photophysical properties proves that the constructed nanoprobe has excellent photochemical properties,including high sensitivity and selectivity,rapid response,easy operation,good stability,and adjustable fluorescence color.In addition,we also explored the FA monitoring ability of this nanoprobe in food and wood,and the test results were basically consistent with the traditional UV spectrophotometer method,which shows that the method has broad application prospects in real samples.2.High-throughput detection technology is helpful for the simultaneous detection of multiple samples,but there is still a lack of highly sensitive,simple and portable high-throughput detection equipment.Therefore,this chapter proposes a FA paper-based detection device based on the fluorescence method.The hydrophilic and hydrophobic detection regions were designed on chromatography paper by wax printing technology.The ratiometric nanoprobes Nano-FAPs and single fluorescent signal Na-FA designed and synthesized above were dropped on the detection area of the paper-based device,and the fluorescence color change of the analyte in the reaction area was observed and captured.Then use the software to read the RGB values and perform data analysis,and further establish a standard curve for the ratio of FA concentration to the color intensity of different channels,thereby realizing the ratio analysis and determination of FA.The method has the advantages of rapid response,low cost,short time consumption,high sensitivity and simple operation,can detect tens of millions of samples at the same time,and has broad commercial application prospects.3.Traditional paper-based device testing requires complex manual operations and sample preparation processes.Therefore,it is of great significance to develop an intelligent and automated portable analysis and detection device.To this end,this chapter designs a smartphone-based FA optical detection system.The system obtains images by taking photos with mobile phones,combines the known functional relationship between FA concentration and fluorescence color ratio,and calculates the FA content value of the unknown image based on the chromaticity values of the standard sample and the sample to be tested.While improving the detection efficiency,this method also breaks the limitation of application scenarios and has the advantages of fast detection speed,high reliability and integration,short time consumption,simplicity and convenience,etc.In addition,the optical detection system successfully realized the detection of FA content in real samples,such as wood,etc.,demonstrating its ability to detect FA on-site and providing an effective tool for the portable detection of volatile gases.