Detection of mercury ions in water environment based on bi-color quantum dot multilayer films.

Objective To establish a method for determination of mercury ions in water environment. Methods The functional multilayer films were assembled by layer-by-layer(Lb L) deposition of oppositely charged Cd Te quantum dot(QDs) and poly(dimethyldiallylemmonium chloride)(PDDA). The bi-color quantum dot multilayer films were used as fluoresce probes for the quantitative determination of trace amounts of Hg2+ based on the evident quenching action of Hg2+ on the fluorescence of Cd Te QDs. Results Experimental results showed that the quenching in fluorescence intensity of multilayer films was linearly proportional to the concentration of Hg2+ in the range of 1.0×10-9 to 1.0×10-5 mol/L and the detection limit was 2.5×10-10 mol/L. Conclusion Compared with the traditional Hg2+ detection method, this method has the advantages of simplification, rapidness, high selectivity and high sensitivity. Furthermore, the proposed method was applied to the determination of trace Hg2+ in water samples with satisfactory results.