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A novel sandwich-type photoelectrochemical (PEC) aptasensor for the carcinoembryonic antigen (CEA) assay was fabricated by taking advantage of the CEA aptamer, Au/BiVO4 and CdS quantum dots (CdS QDs). In virtue...

In this study, oxidized maltodextrins with a high concentration of carboxyl groups were produced using CuSO4 as a catalyst and H2O2 as an eco-friendly oxidant. Infrared spectroscopy, proton-nuclear magnetic resonance spectroscopy, and thermogravimetric analysis were utilized to examine the structure and properties of oxidized maltodextrins. The reaction conditions were optimized in terms of oxidant content, catalyst content, temperature, pH, and reaction time. The prepared oxidized maltodextrin had a carboxyl group content of 105% under the conditions of 200% molar H2O2, 1% molar catalyst, 55 °C, initial pH = 9.7, and 2 h reaction time. In comparison to the commonly used sodium hypochlorite oxidation process, the carboxyl group content was increased by 58%.

Furfural compounds are unique flavor substances in the food industry, but they have a certain carcinogenic effect when accumulated in human body. Therefore, quantitative analysis of furfural compounds is very important in food industry and environmental detection. In this experiment, coumarin hydroxylamine was used as fluorescent label to derive furfural compounds by nitronization reaction, and the contents of furfural, 5-methyl furfural and 5hydroxymethyl furfural in milk powder were accurately determined by liquid chromatography-fluorescence detection. The method has the advantages of high selectivity, wide linear range and low detection limit. This innovative experiment is based on the latest research results, and is developed into a research design experiment in "comprehensive chemistry laboratory" course of applied chemistry major. Through all-round experimental operation and training, students can fully understand the relationship between fluorescence and molecular structure, the design and selection of fluorescent derivative reagents, the detection principle and application of modern analytical instruments. By optimizing the test conditions and derivative reaction conditions of the instrument, students can learn how to optimize the experimental design and understand the basic process of scientific research. Thus, it can stimulate students' interest in scientific research, improve their operational ability, cultivate their scientific spirit of diligent thinking, and enhance their innovative ability and comprehensive quality.