Classification and Discrimination of Pyridine-Based Compounds with Various Substitutions Using Fluorescent Carbon-dots Sensor Array

Pyridine derivatives are important chemical compounds with widespread applications in variousfields [1]. Several pyridine derivatives play important roles in biological systems [1]. Thisring system is present in a number of natural products such as vitamins, niacin, niamide, vitamin-B6, alkaloids, nicotine, and pipeline [1]. So, detection and identification of differentpyridine-based compounds with similar structures is of great interest. Carbon dots (C-dots)are kind of fluorescent materials that have drawn increasing attention in recent years owing toexceptional advantages such as high optical absorptivity, chemical stability, biocompatibility,and low toxicity [2]. Moreover, fluorescence quenching is a promising technique for chemicalsensing applications and widely used for identification and quantitation of various analytes[3]. In this work, we have developed a facile fluorescent sensor array based on fluorescentcarbon dots for detecting and differentiating some pyridine derivatives. Three kinds of nitrogen-doped carbon dots have been synthesized. These carbon dots have various surface statesand thus exhibited diverse quenching responses to different target analytes. The fluorescenceresponse was measured after incremental addition of analyte solutions i.e. 4-methyl pyridine,4-pyridine carboxylic acid, 4-pyridinol, 2,3-pyridindiol, pyridine-3-carboxylic acid, 3-pyridine carboxamide, and 2-pyridine carboxylic acid. Implementation of the principal componentanalysis (PCA) and linear discriminant analysis (LDA) to the collected data matricesallowed the successful classification of all seven pyridine compounds with good accuracy. Inaddition, the binary and ternary mixtures of the seven pyridine compounds can also be wellrecognized with this sensor array. This method is simple, and the sensor arrays could be obtainedeasily with low-cost.