碳量子点/壳聚糖复合物的制备及用于槲皮素检测

以柠檬酸三钠、11-氨基十一烷、聚乙二醇400为碳源,利用微波法制备了碳量子点,将其与壳聚糖反应,制备出碳量子点/壳聚糖复合物。采用荧光、紫外、红外光谱等对碳量子点和碳量子点/壳聚糖复合物进行表征,探究了温度、时间、缓冲溶液及pH对体系荧光强度的影响。在pH 7.6的硼酸—硼砂缓冲介质中,槲皮素可使碳量子点/壳聚糖复合物发生荧光猝灭,其猝灭程度与槲皮素浓度呈良好的线性关系,据此建立了碳量子点/壳聚糖荧光猝灭法测定槲皮素的新方法,方法线性范围为4~40μmol/L,相关系数为0.9940,检出限为0.5μmol/L。方法已应用于测定本地甜瓜中槲皮素的含量。

Preparation of carbon quantum dot/chitosan complex and its application in determination of quercetin

Carbon quantum dots were prepared via microwave method by using trisodium citrate,11-aminohendecane,and polyethylene glycol 400 as carbon source.Then,combining it with chitosan,the carbon quantum dot/chitosan complex was obtained.The carbon quantum dot and the carbon quantum dot/chitosan complex were characterized by fluorescence spectra,ultraviolet spectra and infrared spectra.The effects of temperature,time,buffer solution and pH on fluorescence intensity were investigated.Results showed that quercetin can quench the fluorescence of carbon quantum dots/chitosan complex in a boric acid-borax buffer solution medium with pH of 7.6,and the fluorescence quenching intensity has a good linear relationship with the concentration of quercetin.Moreover,this work established a new method for the determination of quercetin by fluorescence quenching of carbon quantum dots/chitosan complex.This method had a linear range of 4-40μmol/L,with correlation coefficient of 0.9940,and limit of detection of 0.5μmol/L.The method was successfully applied to determine the contents of quercetin in sweet melon(produced in xinzhou,Shanxi)with satisfactory results.