Real-time monitoring of the dissolution of silver nanoparticles by using a solid-contact Ag+-selective electrode.

The dissolution kinetics of silver nanoparticles (Ag NPs) to Ag+ ions is a critical factor determining the toxicity of silver nanoparticles. In this work, a solid-contact Ag+-selective electrode (Ag+-ISE) is fabricated and used to monitor the dissolution of Ag NPs. Ordered mesoporous carbon is compared with disordered mesoporous carbon as the solid-contact material for the Ag+-ISE. The ordered mesoporous carbon based solid-contact Ag+-ISE shows a linear potential response in the range of 1.0 × 10-6-1.0 × 10-3 M AgNO3 with the slope of 55.6 ± 0.8 mV/dec (n = 7) and the detection limit of 10-6.8 M. The solid-contact Ag+-ISE is used to monitor the concentration changes of Ag+ during spontaneous dissolution of Ag NPs in deionized water, and the dissolution kinetics of Ag NPs is consistent with that obtained by inductively coupled plasma-mass spectrometry (ICP-MS). Stimulated dissolution of Ag NPs induced by addition of H2O2 to the Ag NP solution is also investigated by the proposed solid-contact Ag+-ISE. This work provides a fast tool for charactering the dissolution of Ag NPs to Ag+ in real time, which is important for studying the toxicology of nanoparticles.