Carbon dots-based fluorescent probe for trace Hg2+ detection in water sample

A facile and green method was developed to prepare amino-functionalized fluorescent carbon dots (FCDs) for the detection of Hg2+ in aqueous solution. The water-soluble FCDs with the diameter around 3-5 nm were synthesized using anhydrous citric acid as carbon sources, NaBH4 as reducing agent and ammonia as passivation agent. The as-prepared FCDs exhibit blue emission at 440nm with quantum yield as high as 36% using quinine sulfate as reference. The fluorescence intensity of the FCDs can be quantitatively quenched by Hg2+ with high sensitivity and selectivity. The FCDs were successfully applied to the measurement of Hg2+ in water samples with a detection limit of 20 nmol L-1 (3 sigma, n=9), indicating that the amino-functionalized FCDs probe can be potentially applied to the detection of trace Hg2+ in water samples. (C) 2015 Elsevier B.V. All rights reserved.