title: Graphene quantum dot as a green and facile sensor for free chlorine in drinking water.
abstract: 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.
authors.affiliation: Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, and Department of Chemistry, Fuzhou University, Fujian 350108, China.
authors.forename: Yongqiang
authors.initials: Y
authors.lastname: Dong
authors.forename: Geli
authors.initials: G
authors.lastname: Li
authors.forename: Nana
authors.initials: N
authors.lastname: Zhou
authors.forename: Ruixue
authors.initials: R
authors.lastname: Wang
authors.forename: Yuwu
authors.initials: Y
authors.lastname: Chi
authors.forename: Guonan
authors.initials: G
authors.lastname: Chen
mesh_terms: D002713:Chlorine / Q000032:analysis*; D060766:Drinking Water / Q000737:chemistry*; D005453:Fluorescence; D006108:Graphite / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D045663:Quantum Dots; D013055:Spectrophotometry, Infrared; D013056:Spectrophotometry, Ultraviolet
chemical_list: D060766:Drinking Water; D002713:Chlorine; D006108:Graphite