Single-particle ICP-MS (SP-ICP-MS) is a qualitative and quantitative ICP-MS instrument and associated detection method for low-concentration single particles containing specific elements. Single-particle targets can be either nanoparticles or PM2.5/PM10, or synthetic ultrafine particles and clathrates, or the life-saving scientific research frontier cells, algae, viruses and other living small particle targets. Compared to traditional elemental methods, SP-ICP-MS technology is fast and efficient and provides more information: it can measure particle size distribution, number of particles, concentration of elements inside the particles, and concentration of elements dissolved outside the particles. Moreover, it is able to distinguish specific particles containing different elements. The SP-ICP-MS principle is based on measuring the signal strength and signal width produced by a single particle. The suspended single particles must be effectively diluted, with a certain interval between the particles to ensure that only one single particle arrives in the plasma of the ICP-MS at a time for high-speed cracking, then atomized and ionized, each particle produces a pulse signal in ICP-MS, and the width and height of the pulse signal represent the concentration of elements in the particle. The continuous signal represents the concentration of the dissolved element or solvent background element.
When SP-ICP-MS is combined with a customized single-cell injection interface system and the latest data analysis software system, it can be used for single-particle analysis of algae, cells, etc. In this case, the technique is called single-cell ICP-MS. To ensure the reliability of the assay data, the algae or cells must be intact and bioactive before entering the plasma of the ICP-MS. Algae or cell granules can be up to 100 microns in diameter and can easily break or lose their vitality during sample transport, so the single cell ICP-MS injection system is tailored. In addition, since multiple nanoparticles may exist in algae or cells, the number of nanoparticles in the cell must be counted independently or in terms of the number of cells, and a specific setting is required in software.
The main content of this report is from the research work of PerkinElmer and its partners, and introduces the application of PerkinElmer SP-ICP-MS single particle and single cell analysis in environmental analysis.