Study On The Synthesis Of Carbon Quantum Dots And Its Application In Pharmaceutical Analysis

Carbon quantum dotsas a new type of fluorescent carbon nanomaterial have been gaining much attention for its excellent optical propertiesand potential application s. Carbon quantum dots not only overcome the defect of conventional quantum dots but alsohave tunable excitation and emission wavelengths, resistant to photobleaching, excellent biocompatibility, and good water-solubility. Carbon quantum dots has widely used in the field of analysis, bioimaging, drug carriers and so on. Fluorospectrophotometry, which exhibits fascinating features, including its accuracy, simplicity, high sensitivity and inexpensive instrumentation, has been applied in many fields such as chemistry, biology, environmental protection, medicine, biology, geology and metallurgy. In our work, we use different raw materials to synthesize silicon doped carbon quantum dots and nitrogen carbon quantum dots with different characteristics and applied them in berberine hydrochloride and tetracycline sensing, respectively. The main aspects are as follow:(1) A one-pot hydrothermal synthesis of Si-doped carbon quantum dots with upconversion fluorescence as fluorescent probes for berberine hydrochloride detection. A water-soluble silicon-hybrid carbon quantum dots(Si-CQDs) with high fluorescent quantum yield was synthesized by facial one-step hydrothermal method using 3-aminopropyltrimethoxysilane as carbon source. As a biocompatible and most environmentally friendly element, the doping of Si heteroatoms benefits the generation of Si-CQDs with good biocompatibility. The obtained Si-CQDs have been capped with abundant Si-OH at their surfuce, which improved the hydrophilicity and stability in an aqueous system and are convinient for surface modification and their potential applications in many fields. The fluorescence of Si-CQDs was efficiently quenched by berberine hydrochloride, and the fluorescence intensity decreases linearly with berberine hydrochloride. Then, the as-prepared Si-CQDs were employed as a probe for highly sensitive and selective detection of berberine hydrochloride(BH). The mechanism of the fluorescence quenching of the Si-CQDs was studied.The synergistic action of the static quenching effect(SQE) and the innerfilter effect(IFE) resulted to the intensive fluorescence suppression.(2) One-pot low-temperature synthesis of p H-sensitive N-doped carbon dots for detection of tetracycline hydrochloride.N-doped carbon quantum dots(N-CQDs) with high quantum yield and strong photoluminescent were successfully prepared through 60 min carbonization approach using sodium citriate as a carbon source and formamide as a nitrogen source. The carbon quantum dots exhibited p H depending on luminescence, which can used to p H sensing. The particle size, luminescent properties and stability of carbon quantum dots were investigated. It is foundthe as-obtained NCQDs display excellent water solubility, biocompatibility, low toxicity and high photostability. Furthermore, the addition of tetracycline hydrochloride could effective quench the fluorescence of N-CQDs, and the response toward tetracycline was highly linear(0.9989) over the concentration range from 0.5 to 150μM with the detection limit down to 50 n M. Therefore, a novel protocol for tetracycline hydrochloride detection was established.