Time Resolved Inductively Coupled Plasma Quadrapole Mass Spectrometry (TR-ICP-Q-MS): a novel approach for the characterization of Ag-Based Nanomaterials

Particle size, which includes size distribution and aggregation state, is argued to be one of the most important properties to quantify when conducting toxicity tests [1]. Unfortunately, characterization of nanoparticle size for toxicity testing is complicated by the fact that size is not constant among different matrices and concentrations, or even across time in the same matrix [2]. In this work, the proof of concept of a novel approach based on time resolved analysis coupled to ICP-Q-MS for media independent determination of Ag nanomaterials, is introduced. Time resolved ICP-Q-MS provides information about the nanomaterials concentration and size distributions at mass concentration levels down to ng L−1.For time resolved measurements, the suspensions of Ag-based nanomaterial were sufficiently diluted (ng L−1 level), then 0.3 ms integration time was used in order to measure the intensity of a nanomaterials as a single pulse. Under such conditions, the frequency of the pulses is proportional to the number concentration of Ag-based nanomaterials and the intensity of each pulse is related to the nanomaterials size.The efficiency of TR-ICP-Q-MS over other techniques for nanomaterials characterization and quantification are the minimal sample preparation, the superior sensitivity and the element specificity. It also enables the simultaneous measurement of both the dissolved and particulate forms as well as a size distribution analysis for nanomaterials.