Preparation method of high-fluorescent fluorescence carbon quantum dots and application of high-fluorescent fluorescence carbon quantum dots in Cr (VI) detection

Abstract

The invention discloses a preparation method of high fluorescent fluorescence carbon quantum dots. The preparation method comprises the following specific steps: A, dissolving 0.1 to 10g of citric acid and 0.1 to 10g of glycine into 1 to 20mL of water; B, putting a high pressure reactor into a baking oven, heating for several hours under the condition of high temperature and then carrying out natural cooling to room temperature, thus obtaining dark brown suspension containing the fluorescence carbon quantum dots; C, centrifuging the obtained dark brown suspension to remove large particles, using the means of adsorption with macroporous resin, size exclusion chromatography gel or dialysis, purifying a coarse product by using water as eluant and purifying the fluorescence carbon quantum dots; D, concentrating the purified product by using a rotary evaporator at the temperature of 45 DEG C and carrying out freeze-drying to obtain purified fluorescence carbon quantum dots which are white powder. The preparation method of the high fluorescent fluorescence carbon quantum dots, disclosed by the invention, has the advantages of low cost, simple and controllable preparation process, simpleand convenient operation, high sensitivity and selectivity, intuitive detection results and capability of realizing quantitative detection; the obtained carbon quantum dots have the advantages of highquantum yield, long fluorescence life as well as higher detection sensitivity and stability.

Description

technical field [0001] The invention relates to the technical field of preparation and application of a fluorescence sensor with high fluorescence performance, in particular to a preparation method of a fluorescent carbon quantum dot with high fluorescence performance and its application in Cr(VI) detection. Background technique [0002] In the prior art, chromium is a widely used industrial material. Over the past few decades, industry and other anthropogenic processes have continuously released heavy metal ions into the environment. Cr(VI) is a toxic The World Health Organization has proposed a guideline limit of 0.05 mg / L for Cr in drinking water to detect Cr(VI) in order to monitor and reduce the risk of excessive Cr(VI) intake, especially in beverages and The risk in food is very important. In recent years, many analytical techniques have been successfully developed for the determination of Cr(VI) in different sample matrices, such as spectrophotometry, spectrofluoromet...

AI Technical Summary

Problems solved by technology

[0002] In the prior art, chromium is a widely used industrial material. Over the past few decades, industry and other anthropogenic processes have continuously released heavy metal ions into the environment. Cr(VI) is a toxic The World Health Organization has proposed a guideline limit of 0.05 mg / L for Cr in drinking water to detect Cr(VI) in order to monitor and reduce the risk of excessive Cr(VI) intake, especially in beverages and The risk in food is very important. In recent years, many analytical techniques have been successfully developed for the determination of Cr(VI) in different sample matrices, such as spectrophotometry, spectrofluorometry, flame atomic absorption spectrometry, inductively coupled plasma Bulk mass spectrometry, diffuse reflectance-Fourier transform infrared spectroscopy, etc., however, most of these methods are inconvenient due to the need for expensive equipment and complex pretreatments, limiting their use in rapid detection, and therefore, are highly desirable for development. A simple, sensitive, selective and low-cost method for Cr(VI) detection; fluorescent carbon quantum dots are a new type of carbon nanomaterials, due to their unique physical and chemical properties, such as low cost, simple synthesis route, Better biocompatibility, lower toxicity, high light and chemical stability, tunable excitation and emission spectra, these excellent properties make CD as a very potential nanosensor and has been successfully used in pH, Fluorescent detection of metal ions and biomacromolecular substances, however, still has several shortcomings that limit the further application of fluorescent carbon quantum dots. Ligand charge transfer) requires an intermolecular interaction between the chemical sensor and the target molecule, thus making the method complex and time-consuming, thus limiting practical applications. On the other hand, the quantum yield is a key indicator of fluorescent materials and is An important fundamental property that determines whether luminescent materials can be used in practical applications. The low quantum yield leads to low sensitivity in the detection system, which is one of the obstacles that prevent fluorescent carbon quantum dots from being used as fluorescent sensors. In order to overcome these shortcomings, high Quantum Yield of Fluorescent Carbon Quantum Dots and the Design of Fluorescence Measurement Systems Based on Alternative Mechanisms In the inner filter effect, since changes in absorbance are transformed exponentially into changes in fluorescence intensity, the sensitivity of this method is enhanced and can be compared with other mechanisms, based on The fluorescence measurement system of fluorescent carbon quantum dots with internal filter effect has been successfully developed. At the same time, doping is an effective method to improve the quantum yield. For example, B, N, S and P can improve the emission properties of carbon quantum dots. Among them, N doping Therefore, it is of great significance to develop fluorescent carbon quantum dots with high fluorescence performance for the detection of Cr(VI).

Images