碳量子点增强气液相化学发光检测二氧化碳

Enhanced Gas-Liquid Chemiluminescence by Carbon Dots for Determination of Carbon Dioxide

采用一步溶剂热法合成了能够发射绿色荧光的水溶性碳量子点(CDs),并对其进行了透射电子显微镜(TEM)、紫外可见光谱、荧光光谱以及红外谱图等一系列表征。基于该CDs增强的H_(2)O_(2)-KOH-CO_(2)气液相化学发光体系,利用自助研发的气液相化学发光检测仪实现了对CO_(2)气体的实时在线检测。研究了H_(2)O_(2)、KOH以及CDs浓度对发光强度的影响,结果表明当H_(2)O_(2)浓度为0.15 mol/L、KOH浓度为0.40 mol/L以及CDs溶液与KOH溶液体积比为1∶2时所测得的化学发光强度最大。在最优条件下,在0.196~49 mg/L范围内,CO_(2)浓度与发光强度呈现出良好的线性关系;计算得到二氧化碳的检测限为0.049 mg/L;重复检测11次1.96和4.56 mg/L的CO_(2)的相对标准偏差分别为1.46%和0.65%。采用该方法检测CO_(2)具有灵敏度高、选择性好、精密度高以及能够实现连续在线检测等优点。

In this study,water-soluble carbon dots(CDs)that emit strong green fluorescence under the radiation of ultraviolet light was synthesized by one-step solvothermal method and characterized by transmission electron microscopy(TEM),ultraviolet-visible(UV-Vis)absorption spectrometry,fluorescence spectrometry and Fourier transform infrared spectrometry(FT-IR).Specially,this CDs could enhance the chemiluminescence(CL)of H_(2)O_(2)-KOH-CO_(2) gas-liquid CL system.Based on this phenomenon,a CL method for on-line detecting carbon dioxide was developed by using home-made gas-liquid CL detector.In order to find the optimum detection conditions,the concentrations of H_(2)O_(2),KOH and CDs was studied.As a result,the maximum CL is obtained when the concentrations of H_(2)O_(2) and KOH are 0.15 mol/L and 0.40 mol/L,respectively,and the volume ratio of CDs to KOH is 1∶2.Under these optimum detection conditions,there is a good linear relationship between CL intensity and carbon dioxide level in the range of 0.196~49 mg/L,and the limit of detection is 0.049 mg/L.The reproducibility is tested by measuring 1.96 and 4.56 mg/L carbon dioxide eleven times,and the relative standard deviations(RSD)are 1.46%and 0.65%,respectively.A CL method for detecting carbon dioxide has been successfully developed with high sensitivity,high selectivity,low cost and strong timeliness.