Application of Luminescent Effects In CdSe/CdS/ZnS Quantum Dots for the Determination of Sulphur-Containing Impurities in Mixtures of Hydrocarbons and Oils

The article is dedicated to the development of a new method for the sulphur-containing compound impurities analysis in mixtures of liquid hydrocarbons and corresponding oil fractions, based on the quenching of CdSe/CdS/ZnS quantum dots photoluminescence effect. The control of quantitative content of such impurities in oil samples is very important for the organization of the processes of its further processing and subsequent wide practical application. The work uses specially developed methods for the synthesis of CdSe/CDs/ZnS quantum dots, containing a semiconductor core, coated with a composite shell consisting of semiconductor and dielectric layers, as well as a fluorinated polymer porous layer. This technique made it possible to achieve a high quantum yield of photoluminescence (80–90) %, high temporal stability of luminescence in the range of (580–650) nm, as well as good compatibility of quantum dots with liquid hydrocarbon media. For the analysis, a special luminescent sensor was manufactured, which allows measuring the presence of organic sulphur-containing impurities with high sensitivity: (10–5 – 10–4) mg/kg. The technique is low-cost, allows the use of compact equipment and can be used to conduct operational analysis in real time.