Flow field-flow fractionation and single particle inductively coupled plasma mass spectrometry as a powerful tool for tracking and understanding the sensing mechanism of Ag-Au bimetallic nanoparticles toward cobalt ions

Background: Ag - Au bimetallic nanoparticles (BNPs), synthesized by using citrate reduction of Ag and Au ions, were used as sensor for detection of Co 2 + . In order to optimize sensing performance, it is necessary to control the particle size and size distribution of the original Ag - Au BNPs. Therefore, analytical methods based on the use of single particle inductively coupled plasma mass spectrometry (SP-ICP-MS) and flow -field flow fractionation (FlFFF)-ICP-MS were developed to track the signal of Ag and Au in bimetallic nanoparticles at each step of the procedure: BNP synthesis, aggregation and sensing in order to understand the sensing mechanism. To better understand colorimetric sensing of Co 2 + using Ag - Au BNPs, various solution mixtures were analyzed by using SP-ICP-MS and FlFFF-ICP-MS.