ICP-MS analysis

What is ICP-MS?

ICP-MS is a high-throughput elemental analysis method that is capable of detecting most of the elements in the periodic table. Modern ICP-MS instruments offer linear dynamic ranges up to twelve orders of magnitude. This enables simultaneous analysis of major and minor elemental components of the sample.

Besides low-concentration (ppb=parts per billion=µg/l) accuracy, ICP-MS performs reliably in ultra-low concentrations (ppt=parts per trillion=ng/l and even ppq=parts per quadrillion). The method is capable of measuring atomic mass ranging from 7 to 250, which means that it detects elements from lithium to uranium. ICP-MS can also distinguish different isotopes of elements.

How does ICP-MS work?

ICP-MS uses high-temperature plasma to break down chemical compounds in a sample into their atomic ions. These ions are then introduced into a mass spectrometer, where they are separated and detected according to their mass-to-charge ratio (m/z) to distinguish and quantify different elements and, in some cases, their isotopes.

Inductively coupled plasma-mass spectrometry is most often used to analyze solid or liquid samples, but gas analysis is also possible. Most common ICP-MS instruments rely on liquid injection, meaning that solid and gaseous samples must be dissolved in liquids before the analysis. With solid samples, this is most often achieved through acid digestion with hot mineral acids. An example of such a pretreatment method for solids is vapor phase decomposition, which can be combined with ICP-MS in VPD-ICP-MS analysis. Gases, on the other hand, can be trapped in suitable liquids by bubbling.

If sufficient results cannot be achieved through the pretreatment of solid or gaseous samples, special instruments can be used to investigate these samples without a dissolving pretreatment. For example, LA-ICP-MS (laser ablation inductively coupled plasma mass spectrometry) can be used to analyze the surfaces of solid samples directly.

The difference between ICP-MS and ICP-OES

The principle of ICP-MS is measuring the mass-to-charge ratio of ions through mass spectrometry, as explained above. ICP-OES (inductively coupled plasma-optical emission spectroscopy), on the other hand, identifies elements by measuring the characteristic wavelengths of light emitted by excited atoms and ions in the plasma.

The difference in use cases is that ICP-MS typically achieves lower detection limits, making it better suited for trace elemental analysis of clean samples such as pharmaceuticals and ultrapure water. ICP-OES is a more robust method for analyzing samples that have a higher amount of total dissolved solids. Examples of this type of sample include wastewater, soils, and solid waste.

The two techniques are often used together in multi-element environmental analysis. For a practical illustration, see this example report: ICP analysis of seawater samples.

What is ICP-MS analysis used for?

ICP mass spectrometry is most often used in multi-element trace studies. It can, for example, be used to analyze heavy metal contamination of food, water (including ultrapure water samples), consumer goods, or pharmaceutical products. Other trace metal studies are also common. In solvent purity assays, ICP-MS can be combined with GC-FID and Karl Fischer titration to obtain comprehensive data on possible contaminants.

Need ICP-MS analyses?

Measurlabs offers high-quality laboratory testing with ICP-MS for environmental samples, food, pharmaceuticals, and a range of other sample types. We offer competitive pricing and have specialized partner laboratories for different matrices, guaranteeing that your samples are always analyzed by experts in the specific field. Contact us through the form below to get a custom offer, and we will get back to you by the next business day.