Application Of Adsorption Materials In QCM Electrochemical Analysis And Trace Detection

In the twenty-first Century, with the growth of the world economy and the development of science and technology, many studies have been concerned to improve the detection technology. In this thesis, three materials (graphene, MOFs and COFs) which with high specific surface area and strong adsorption properties were selected as modifiers and enrichment materials in the application of new detection technology (QCM and solid UV detection). The details are as the followings:1. The electrochemical quartz crystal microbalance (EQCM) technique was used to study the adsorption of adenine (A) and guanine (G) by using the with or without AuNPs@RGO modified electrode as indicating electrode. The results showed that the modified electode showed excellent electro-catalytic activity for adsorption of A and G. According to the results, the value of △F of A is 80 Hz, and the value of △F of G is 56 Hz. The limit of detection of the A and G were estimated to be 1.1nmol/L and 2.8nmol/L, respectively.2. Mg-BTC hollow nanosphere was successfully obtained using PS nanosphere as template, and used to modify the Au electrode. The value of BET of the hollow Mg-BTC nanosphere is 774.514m/g, which provided more adsorption sites as target molecule. According to the results of the QCM measurement, the values of △F of nitrotoluene, m-nitrotoluene and nitrobenzene were 40Hz,42Hz and 70Hz, respectively. Compared with the gold electrode without modified, all these values were enhanced 1.5,2 and 3 times, respectively. The detection limit of the nitro compounds was 1.8nmol/L. Thus it can be seen that Mg-BTC hollow nanosphere shows excellent adsorption and after modified the Au electrode, it can be used as a probe to detect the nitro compounds.3. Covalent organic frameworks of polyimide (PI) nanosheets were facilely prepared under microwave condition by using cyanurotriamide and pyromellitic dianhydride as raw material, and ZnCl2 act as catalyst. The value of BET of PI nanosheet is 193.424m2/g. The adsorption capacity of the sample for rhodamine B was 645mg/g, and the adsorption rate reach 98% within 2 hours. According to the results of the solid ultraviolet measurement, the detection limit of the dyes was estimated to be 0.4μg/L. A simple method for dye detection is constructed, which provides a new way for the detection of low concentration dye pollutants in reality.