Laser Ablation ICP-MS (LA-ICP-MS)
Laser-Ablation ICPMS (LA-ICPMS) is a variant of ICPMS that allows for direct, versatile elemental analysis of solid samples with minimal sample preparation.
Instead of spraying a fluid into the plasma chamber, as is done in conventional ICPMS measurements, LA-ICPMS applies a high-power, pulsed laser beam to the sample surface to induce photolysis. This process frees ion fragments from the surface, which are transported via a carrier gas (typically He or Ar) to the plasma chamber. As in ICPMS, the plasma digests the gaseous sample ions into their constituent elemental isolates. These are then separated through a mass analyzer by mass / charge (m/z) ratio, producing the final spectrum.
This technique is moderately surface-specific (information depth is up to 1 um), and can accurately quantify elemental composition to ppb sensitivities, even with very small sample quantities (e.g. picograms). LA-ICPMS also allows for chemical mapping of the surface, as the beam spot can be focused to micron-scale and scanned over an analytical area on the sample.
Application Areas for LA-ICP-MS
LA-ICP-MS is a more generalizable mass spectroscopy technique for semi-surface specific solid-state chemical analysis. It can be used in spatial mapping applications to capture surface chemistry, or for highly efficient chemical characterization with no vacuum mandate and limited sample preparation. It is used in environmental assays, food safety checks, forensic analyses, as well as industrial process control and quality assurance, biochemical research, and geology.
Measurements from ICP-MS
- Elemental composition of solid samples
- Isotope analysis
- Elemental mapping of sample surface
USES & LIMITATIONS FOR ICP-MS
- What it is great for:
- Identification and measurement of trace elements (detection threshold as low as ppb)
- Chemical mapping (limit spatial resolution to ~100um)
- Minimal sample preparation for most solids
- Data interpretation can be time consuming
- Accurate quantification requires scanning matrix-matched reference materials
EXAMPLE OUTPUTS OF LA-ICP-MS
LA-ICP-MS linescan of Beryllium in Sapphire
Plots show Be concentration (ppm) in 2 sapphire samples taken across a line-scan of a cut face in the stone (500um and 300um in length, respectively from top-down). Both were subjected to heat treatments.
From Agilent Technologies Applications Note: https://www.agilent.com/cs/library/applications/5989-1266EN.pdf