Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, and Department of Chemistry, Fuzhou University, Fujian 350108, China.
Anal Chem. 2012 Oct 2;84(19):8378-82. doi: 10.1021/ac301945z. Epub 2012 Sep 21.
Free chlorine was found to be able to destroy the passivated surface of the graphene quantum dots (GQDs) obtained by pyrolyzing citric acid, resulting in significant quenching of their fluorescence (FL) signal. After optimizing some experimental conditions (including response time, concentration of GQDs, and pH value of solution), a green and facile sensing system has been developed for the detection of free residual chlorine in water based on FL quenching of GQDs. The sensing system exhibits many advantages, such as short response time, excellent selectivity, wide linear response range, and high sensitivity. The linear response range of free chlorine (R(2) = 0.992) was from 0.05 to 10 μM. The detection limit (S/N = 3) was as low as 0.05 μM, which is much lower than that of the most widely used N-N-diethyl-p-phenylenediamine (DPD) colorimetric method. This sensing system was finally used to detect free residual chlorine in local tap water samples. The result agreed well with that by the DPD colorimetric method, suggesting the potential application of this new, green, sensitive, and facile sensing system in drinking water quality monitoring.
游离氯被发现能够破坏通过热解柠檬酸获得的石墨烯量子点（GQDs）的钝化表面，从而导致其荧光（FL）信号显著猝灭。在优化了一些实验条件（包括响应时间、GQDs 的浓度和溶液的 pH 值）之后，基于 GQDs 的 FL 猝灭，开发了一种用于检测水中游离余氯的绿色简便传感系统。该传感系统具有许多优点，例如响应时间短、选择性好、线性响应范围宽和灵敏度高。游离氯的线性响应范围（R(2) = 0.992）为 0.05 至 10 μM。检测限（S/N = 3）低至 0.05 μM，远低于最广泛使用的 N-N-二乙基-p-苯二胺（DPD）比色法。该传感系统最终用于检测当地自来水样品中的游离余氯。结果与 DPD 比色法吻合良好，表明这种新型、绿色、灵敏、简便的传感系统在饮用水质量监测中有潜在的应用。
