Selective and Sensitive Detection of Silver(I) Ion Based on Tetracationic Complex and TGA/GSH Co-capped Quantum Dots...

CdTe quantum dots capped with glutathione (GSH) and thioglycolic acid (TGA) were synthesized and the interaction between QDs and tetracationic Fe complex was investigated. Based on the specific interaction between Ag⁺ and cytosine bases (C), we designed a label-free DNA sensor for the detection of Ag⁺ in aqueous solution. Furthermore, tetracationic Fe complex with a higher positive charge is demonstrated to improve the sensitivity of the sensor. A detection limit of 3.3 nmol dm^-3 was obtained, which was lower than in previous reports. This sensor also exhibits promising potential for real sample analysis.