Carbon Quantum Dots-based Sensor Array For Detection Of Organic Acids And Classification Of Cigarettes

The array sensing technique has exhibited numerous advantages,such as strong recognition ability,high accuracy,and diversity,in the identification and detection of various structurally similar substances and mixtures with complicated chemical ingredients.The fluorescent sensor array is favored by researchers owing to its high sensitivity,rapidity of analysis,and overall cost-effectiveness.In this paper,two types of fluorescence sensor arrays were designed by using carbon quantum dots(CDs)with excellent optical and chemical properties as fluorescent indicators.The two sensing systems enabled the detection of organic acid biomarkers in urine and differentiation of different species of cigarettes,respectively.Moreover,the performance of two sensor arrays were further studied in this research.The specific works are as follows:(1)Three kinds of receptors functionalized CDs were synthesized by using 3-aminobenzeneboronic acid as the carbon precursor through a one-step hydrothermal process with three kinds of amino acids as the co-reactant,respectively.Their particle sizes were all around 5–8 nm.Through linear discriminant analysis,the sensor array constructed by three CDs can accurately identify and distinguish seven organic acid biomarkers in urine,with a concentration range of 100 nM–1000 ?M.The interference tests further demonstrated the accurate recognition ability and excellent selectivity of the sensing system to analytes.In addition,the sensing system also realized quantitative detection of homovanillic acid/vanillylmandelic acid in both one-and two-component system under urine environment by the linear discriminant analysis and support vector machine.(2)CDs with an average size of 8 nm were synthesized by microwave method using L-glycine and urea as carbon precursors.A sensor array based on indicator replacement experiments was constructed by using CDs as the single fluorescent indicator and different concentrations of silver ions as fluorescent signal regulators.The multi-channel sensing platform can identify and discriminate twenty-nine cigarettes in terms of the type(flue-cured cigarette,blended cigarette and cigar),brand and origin(domestic and foreign cigarettes)by principal component analysis.In addition,the fluorescent sensor array can sensitively detect nine kinds of tobacco-based chemical ingredients(saccharides,organic acids,and nicotine)and discriminate them between different concentrations.