Gold Nanoparticle Determination by Inductively Coupled Plasma-Mass Spectrometry,Anodic Stripping Voltammetry,and Flame Atomic Absorption Spectrophotometry

Gold Nanoparticles (AuNP) were measured by Inductively Coupled Plasma–Mass Spectrometry (ICP-MS), Anodic Stripping Voltammetry (SV), and flame Atomic Absorption Spectrophotometry (AAS). Experiments investigated the relationships between counts per second (ICP-MS), absorbance (AAS), or μA (SV) and Au concentrations in solutions bearing AuNP with sizes of 5, 15, and 50 nm. Similarly the impact of the solution matrix was assessed using deionized water, 1.0 M HNO₃, 1.0 M HCl (ICP-MS and AAS), and water containing the bacterium E. coli (～10⁶ organisms/mL) by all three types of instrumentation. Each instrument yielded linear calibration curves with a signal proportional to Au concentration over the concentration range 0.02 ppm to 1 ppm.The methods were all reliable when biomacromolecules or when organisms such as E.coli existed in the matrix. Comparing the limits of detection for the three methods, ICP-MS and SV were lower than AAS. Comparing cost, SV and AAS were less expensive than ICP-MS. Comparing time required for each measurement, AAS was shorter than ICP-MS and SV. In comparison of the interfering effects of E-coli, ICP-MS and AAS were less-affected, while SV was more affected. An intact E.coli or organism may be very absorptive on the electrode surface,which reduced the measured anodic currents in SV and also increased the standard deviations.