Simultaneous Enrichment Of Anions And Cations On Paper Fluidic Channel And Application Of Copper Ions Detection

Point-of-care testing(POCT)has been widely used in the diseases diagnosis,food safety testing and environmental monitoring.The standards developed by the World Health Organization should have the following characteristics:cheap,sensitive,user-friendly,fast,out of the device and ultimately deliverable to the user.The paper-based analytical device(PAD)conforms the above requirements.It has received extensive attention in the past decade and has shown potential in the POCT.However,the disadvantage of the low sensitivity of the paper-based analytical device limits its development,combining it with the electric concentration method is of great significance for paper-based applications.The first chapter introduces the paper materials,production process and application of paper-based analytical device.The application aspects mainly include sample collection and storage,sample pretreatment and sample detection methods.The second chapter mainly introduces a "T" type paper-based channel structure to improve the sensitivity of the paper-based analytical device,combines the on-line complexation reaction with the field amplification stacking,and demonstrates the rapid detection of copper ions.The colorimetric signal intensity of Cu2+ that obtained by mobile phone imaging has been improved by three orders of magnitude.A linear relationship in the range of 0.1-1.0 mmol/L Cu2+was obtained(R2=0.991),and a limit of detection of 30 μmol/L was achieved,which is close to that by a desktop spectrophotometer.In addition,the effects of other coexisting metal ions on the detection of Cu2+were also investigated.This study shows that combining a complexation reaction that has a certain selectivity with electric stacking can establish a cheap,simple,and sensitive method for rapid detection of copper ions in a paper-based analytical device.The third chapter introduces the first successful demonstration of the simultaneous separation and enrichment of the anion and cation components on the paper-based fluid channel.The feasibility of the method was visualized using the colored cationic probe Rhodamine 6G and the anionic probe Brilliant blue.The research shows that introducing weak acid and weak base salt can simultaneously produce electric field gradients across the PAD.Under the optimized conditions,the enrichment factor of the anion and cation probes can achieve two orders of magnitude using the colorimetric results by the smart phone.The applicability of this method was further demonstrated by stacking and separation of Cu2+/NO2-and even amphoteric ions-proteins of phycocyanin(blue,pI 4.4,anion probe)and cytochrome C(brown,pI 10.0,cation probe).The method provides a basis for the simultaneous separation and enrichment of various anion and cation components in the sample.