A sensitive and selective sensing platform based on CdTe QDs in the presence of L-cysteine for detection of silver, mercury and copper ions in water and various drinks

Water soluble CdTe quantum dots (QDs) have been prepared simply by one-pot method using potassium tellurite as stable tellurium source and thioglycolic acid (TGA) as stabilizer. The fluorescence of CdTe QDs can be improved 1.3-fold in the presence of L-cysteine (Cys), however, highly efficiently quenched in the presence of silver or mercury or copper ions. A sensitive and selective sensing platform for analysis of silver, mercury and copper ions has been simply established based on CdTe QDs in the presence of L-cysteine. Under the optimum conditions, excellent linear relationships exist between the quenching degree of the sensing platform and the concentrations of Ag+, Hg2+ and Cu2+ ranging from 0.5 to 40 ng mL(-1). By using masking agents of sodium diethyldithiocarbamate (DDTC) for Ag+ and Cu2+, NH4OH for Ag+ and Hg2+ and 1-(2-Pyridylazo)-2-naphthol (PAN) for Hg2+ and Cu2+, Hg2+, Cu2+ and Ag+ can be exclusively detected in coexistence with other two ions, and the detection limits (3 sigma) were 0.65, 0.063 and 0.088 ng mL(-1) for Ag+, Hg2+ and Cu2+, respectively. This effective sensing platform has been used to detection of Ag+, Hg2+ and Cu2+ in water and various drinks with satisfactory results. (C) 2016 Elsevier Ltd. All rights reserved.