Study On The Paper-based Analytical Devices And Its Application

In view of the current environmental pollution, disease and food safety issues, the establishment and improvement of the analytical tools and the analytical methods which are not dependent on the laboratory conditions has become a important matter. In this dissertation, the new analytical methods for measuring nitrite ion, sulfide, salicylic acid, copper ion and mercury ion were proposed, and the corresponding analytical devices were constructed.This dissertation includes the following four chapters:1. IntroductionThis chapter presented the development and the application of the paper-based microfluidic analytical devices. The composition, structure and properties of paper material were also introduced.2. Study on the preparation and application of the paper-based nitrite and sulfide analytical devicesBased on that NO2- can permeate through the hydrophobic chlorinated polyvinyl chloride (CPVC) barrier fabricated in filter paper, the paper-based nitrite detection device by fabricating CPVC barrier in filter paper was carried out. The detection limit of this study method for nitrite was 48 μmol/L, and the linear range for nitrite was 70-1500 μmol/L. With the charactaristics of strong anti-interference, this study method can determine the nitrite in turbid or complex matrix nitrite sample directly.That sulfide ion can permeate through both the hydrophobic filter paper treated with polyvinyl chloride (PVC) and the hydrophobic barrier fabricated in filter paper with PVC were used to construct paper-based sulfide ion selective permeating detection paper and sulfide selective detection device respectively. The sulfide ion selective permeating detection paper method displayed a detection limit of 38 μmol/L for sulfide, and its linear range was 50-2100 μmol/L. The paper-based sulfide ion selective detection device method displayed a detection limit of 36 μmol/L for sulfide, and the linear range for sulfide was 65-2000 μmol/L. With strong anti-interference properties, both methods of measuring sulfide can be used to measure complex matrix sulfide samples directly.3. Study on the preparation and application of the analytical device made from ethylenediamine-functionalized celluloseEthylenediamine-functionalized cellulose was prepared by the reaction of chlorinated cellulose with ethylenediamine. The ethylenediamine-functionalized cellulose supported with copper (Ⅱ) and mercury (Ⅱ) were prepared by the reaction of ethylenediamine-functionalized cellulose with CuCl2 and HgCl2 respectively. After mixing the ethylenediamine-functionalized cellulose supported with copper (Ⅱ) and mercury (Ⅱ) with 1,2-dichloroethane solution of chlorinated polyvinyl chloride, the copper (Ⅱ)-selective adsorption device and mercury (Ⅱ) selective adsorption device were obtained. Using the copper(II)-selective adsorption device to determine Cu2+ in solution, the linear range was 35-1100 μmol/L, and the detection limit was 33 μmol/L. Using mercury (II) selective adsorption device to measure Hg2+ in the sample solution, the linear range for Hg2+analysis was 0.1-55 μmol/L, and the detection limit was 0.06 μmol/L. In this study, the selective affinity sites for Cu2+ and Hg2+ was not created by crosslinking reaction, it paves a new way for the molecular/ionic imprinting techniques.4. Study on the preparation and application of the paper-based selective adsorption analytical devicesEthylenediamine functionalized polymethylmethacrylate was prepared by the reaction of ethylenediamine with polymethylmethacrylate. Based on the interaction between ethylenediamine functionalized polymethylmethacrylate and salicylic acid and the intermolecular forces between ethylenediamine functionalized polymethylmethacrylate and polymethylmethacrylate, a paper-based salicylic acid selective detecting device which had selective affinity to salicylic acid was fabricated. Using this device to measure salicylic acid solution, the adsorption and detection of salicylic acid and the removal of reaction products were carried out successively, the linear range for measuring salicylic acid was 50-2200 μmol/L, and the detection limit was 48 μmol/L.Polyallylamine hydrochloride was coated on filter paper, and then it was changed into polyallylamine. After crosslinking the polyallylamine with epichlorohydrin, the Hg(II) selective adsorption paper was constructed based on the surface imprinting technique.Using this Hg(Ⅱ) selective adsorption paper to measure Hg2+ solution, the linear range for Hg2+ was 0.1-50 μmol/L, and the detection limit was 0.07 μmol/L. This study method has the advantages of easy fabrication, convenient operation and low detection cost.