蛋白胨碳量子点“关-开”型荧光探针检测食品中草酸  

Peptone-derived carbon quantum dots as“off-on”fluorescence probes for the determination of oxalic acid in food samples

作　　者：李影影 冯素玲[1] 李雪 LI Yingying;FENG Suling;LI Xue(School of Chemistry and Chemical Engineering,Henan Normal Universi‐ty,Xinxiang 453007,China)

机构地区：[1]河南师范大学化学化工学院,新乡453007

出　　处：《分析试验室》2022年第5期518-522,共5页Chinese Journal of Analysis Laboratory

基　　金：国家自然科学基金项目(21976052)资助。

摘　　要：采用水热法,使用碳源蛋白胨制得荧光碳量子点(CQDs)。使用透射电镜、X射线光电子能谱(XPS)和红外光谱对其进行了表征。该CQDs溶液的荧光能够被Cu^(2+)猝灭,草酸能够使CQDs的荧光恢复。据此建立了碳量子点“关-开”型荧光探针测定草酸的新方法。荧光恢复程度与草酸浓度在8~65μg/mL范围内呈线性关系,检出限为1.8μg/mL。通过紫外光谱、荧光光谱和荧光寿命探究了CQDs对草酸的荧光响应机理。Cu^(2+)能够对CQDs的荧光产生动态猝灭,C_(2)O_(4)^(2-)与Cu^(2+)结合,减少了溶液中游离的Cu^(2+),导致CQDs的荧光恢复。该方法可用于实际样品西红柿和圣女果中草酸的分析检测。A single-step hydrothermal route was developed for the synthesis of carbon quantum dots(CQDs)by using peptone as carbon source.Transmission electron microscopy,X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy were performed to characterize CQDs.The fluorescence of CQDs was quenched effectively by Cu^(2+).Then,the fluorescence of the solution of CQDs-Cu^(2+)was recovered in the presence of oxalic acid.Thus,the prepared CQDs can be used as"off-on"fluorescence probes for oxalic acid(OA).The calibration curve was linear over the concentration range of 8-65μg/mL,and the detection limit was 1.8μg/mL.The fluorescence response mechanism was investigated by means of UV-vis absorption spectra,fluorescence spectra and fluorescence lifetime measurement.It was concluded that fluorescence of CQDs is significantly quenched by Cu^(2+)ion via dynamic mechanism.And the combination of C_(2)O_(4)^(2-)and Cu^(2+)reduces the free Cu^(2+)in the solution,resulting in the fluorescence recovery of CODs.The proposed method was applied to the detection of oxalic acid in tomato and cherry tomato samples.

关 键 词：碳量子点 荧光探针 蛋白胨 草酸 Cu^(2+) 

分 类 号：O657.3[理学—分析化学] O661.1[理学—化学]