ICP-MS Analysis

Qualitative and quantitative (ppb) elemental analysis

ICP-MS (inductively coupled plasma-mass-spectrometry) is a technique to determine low concentrations (range: ppb = parts per billion = µg/l). ICP (Inductively Coupled Plasma) Spectroscopy is an analytical technique used to measure and identify elements within a sample matrix based on the ionization of the elements within the sample. Mass Spectrometer (MS) separates the ions out by their mass-to-charge ratio after going through the ICP, and the detector counts the number of selected ions per second which allows the instrument to determine the concentration of each chosen element.

ICP-MS analysis requires the use of liquefied sample solutions. The sample solution is introduced into the device where it becomes nebulized in a spray chamber. Aerosol samples are transported into the core of the inductively coupled argon plasma, where they are completely desolvated, atomized, and ionized. These ions are then extracted from the plasma by skimmer and interference cones and extraction lenses. After going through the lenses, the ion particles are further refined by going through an off-axis ion lens removing photons and neutral ions, reducing background noise.

Polyatomic ions which act as interferences are removed using kinetic energy discrimination, where the larger polyatomic ions lose energy faster than the analyte ions and are easily removed from the sample beam. From there, the beam of ions travels into the hyperbolic quadrupole of the mass spectrometer and the ions are separated by their mass-to-charge ratio, allowing only the selected ions to travel on towards the detector to be measured and reported by the ICP-MS in terms of counts per second and concentration. The system can detect element from Lithium to Uranium.