Accurate Determination and Characterization of Gold Nanoparticles Based on Single Particle-Inductively Coupled Plasma-Mass Spectrometry

Abstract An accurate determination method for gold nanoparticles (AuNPs) number concentration and size was developed based on single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS). Influencing parameters such as different calculation methods of transport efficiency, dwell time, dispersing agent and injection mode were investigated and optimized. The transport efficiency has a greater impact on the accuracy of the measurement result, and it should be selected according to the measured target parameters. It was important to keep the stability of the transport efficiency and use the calibration standard calibrating during the measurement process. The dwell time directly affected the precision of result, and the data processing mode should be selected carefully according to the sample type, particle size and other properties. When the dwell time was 0.1 ms, the linear ranges of 30 nm and 60 nm AuNPs were 2–40 pg/g and 10–200 pg/g, respectively, the linear correlation coefficient was greater than 0.9998, the relative standard deviation was less than 3.80%. The detection limits of particle number concentration and particle size were 110 NPs/g and 9 nm, respectively. Four kinds of synthesized AuNPs and international pilot study sample were determined by the established method. The deviation of the number concentration in pilot study from the key comparison reference values was less than 5%. The results were equivalent and the expanded uncertainty was less than 15% (k = 2), which further verified the accuracy and applicability of the method.