Detection of Agglomerates Using Hydrodynamic Chromatography Hyphenated with Single Particle Inductively Coupled Plasma Mass Spectrometry

A method was developed for the detection of nanoparticles and their state of agglomeration by combining hydrodynamic chromatography (HDC) with single particle inductively coupled plasma mass spectrometry (spICP-MS). Gold nanoparticles were measured under different conditions including the simulation of one of the most important human body functions, the human digestion. Nanoparticle detection and characterization was clearly demonstrated by the analysis of individual particles and a mixture of 30, 60, 100 and 200 nm particles at mass-based concentrations in the ngL-1 (ppt) range. For HDC a clear linear relationship was found between the retention time and the square root of the particle diameter. An agglomeration experiment to determine the packing density of the detected particles showed that it is possible to determine whether the detected particles are primary particles or agglomerates. In addition, the application of HDC hyphenated with spICP-MS was able to elucidate the fate of nanoparticles in the gastrointestinal track. The results showed that primary gold particles that enter the body in the saliva stage, agglomerate in the stomach to larger sized agglomerates which de-agglomerate back to the primary particles in the intestine stage. The results of this experiment show that HDC-spICP-MS is able to detect nanoparticles and agglomerates there of in complex matrices.