What is Laser Ablation ICP-MS?
Inductively coupled plasma mass spectroscopy (ICP-MS) is an advanced analytical technique for interrogating the molecular composition of a sample at extremely low limits of concentration.
The conventional ICP method involves the dissolution of sample material in a molten eutectic mixture, which is then nebulized and sprayed through an argon (Ar) plasma torch. Typical temperatures in an ICP array are sufficient to ionize the atoms of virtually any chemical element. These ions are then sampled, segregated, and characterized based on their unique mass-to-charge ratios and spectral characteristics. This technique is widely used to detect and quantify trace elements to sub-parts per million (ppm) limits.
However, new methods of ICP analysis have emerged that support the spectroscopic analysis of solid samples directly. This is an exciting concept for geochemists and mining companies as it could theoretically reduce time spent on costly sample preparation stages of mineral analysis. Laser ablation ICP-MS is one of the most powerful iterations of this technology.
In this blog post, XRF Scientific explores laser ablation ICP in greater depth.
Outlining Laser Ablation ICP
Laser ablation refers to the complex interaction between solid matter and laser radiation. When a continuous wave (CW) or pulsed laser light is focused onto a material, its electronic subsystem and molecular lattice begin to absorb the energy, causing atoms to dissociate from one another. These atoms subsequently ablate, either evaporating, sublimating, or converting directly into plasma. In laser ablation ICP, these ejected particles are transported to the plasma torch where they are ionized and redirected into the mass spectroscopy unit for evaluation.
While CW lasers can be used to ablate sample materials, extremely short laser pulses are preferable for rapid ICP analysis with uniform particle size distributions. Laser ablation ICP increasingly exploits pulses of laser light on the order of femtoseconds, unlocking new levels of precision for chemical analysis of microscale samples that have been subjected to little or no sample preparation.
However, the improved accuracy of laser ablation ICP does not necessarily mean analysts should forfeit sample preparation entirely. Despite the outstanding uniformity of particles generated via femtosecond laser ablation, the mass spectrometer may still be subject to errors caused by heterogeneities and contaminants in the raw material.
By extracting mere milligrams of material from the surface of a sample and fusing it with an appropriate borate salt into a glass bead or disc, analysts can acquire as close to a perfect homogenous representation of the sample as possible. Armed with the most powerful ICP tool currently available and a tried-and-tested sample preparation technique that guarantees sample purity, reliable elemental analysis of samples can now be carried out faster than ever.
ICP-MS Solutions from XRF Scientific
XRF Scientific specializes in the development of instrumentation for high purity sample preparation. We provide unique solutions for both ICP-MS and x-ray fluorescence (XRF) analysis. If you would like to learn more about our range of products for either analytical technique, simply contact a member of the team today.
