Enhancement of QCM Detection for Heavy Metal Ions Based on TGA Modified CdTe Nanospheres

Quartz crystal microbalance sensor was designed based on thioglycolic acid (TGA) modified CdTe nanospheres to detect heavy metal ions in aqueous solution. TGA plays an important role in the adsorption of heavy metal ions, and CdTe nanospheres are used to amplify mass signals. Experimental results show that the sensitivity of the sensor is six times that of the QCM sensor based on TGA only. Frequency shifts show a good linear relationship with the concentration of heavy metal ions. The detection limit for Pb2+, Cd2+ and Cu2+ is 0.096, 0.089 and 0.189 μg/L respectively. This sensing system is also found partially reversible by adding the strong chelating agent to remove the heavy metal ions on the electrode surface.