What is LA-ICP-MS?

LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) is a powerful analytical technology that enables highly sensitive elemental and isotopic analysis to be performed directly on solid samples.

LA-ICP-MS begins with a laser beam focused on the sample surface to generate fine particles – a process known as Laser Ablation. The ablated particles are then transported to the secondary excitation source of the ICP-MS instrument for digestion and ionization of the sampled mass. The excited ions in the plasma torch are subsequently introduced to a mass spectrometer detector for both elemental and isotopic analysis.

Benefits of LA-ICP-MS

LA-ICP-MS is one of the most exciting analytical technologies available because it can perform ultra-highly sensitive chemical analysis down to ppb (parts per billion) level — without any sample preparation.

Samples can be both conducting or non-conducting, and the analysis can be performed in the air without the need for a complex vacuum system. Results are available within seconds; therefore LA-ICP-MS delivers the fastest analysis speed of all analytical techniques with the limit of detection approaching ppb level.

The sample mass size required for LA-ICP-MS analysis is sub-microscale — picograms to femtograms. Traditional liquid nebulization approaches for ICP-MS require the removal of milligrams of sample mass in order to be effective.

When applied with optimized laser ablation conditions and ICP-MS data acquisition protocols, LA-ICP-MS allows versatile solid sampling schemes that include:

• Bulk analysis
• Local inclusion and defect analysis
• Depth profiling
• Elemental/isotope mapping

The two most commonly used laser-based methods are bulk analysis with a typical laser spot size of 100 ~ 350μm and microanalysis with the laser spot size as small as a few microns.

Femtosecond Laser Pulsing

The use of femtosecond laser pulsing represents the latest technical advance in LA-ICP-MS technology. It improves precision and accuracy, reduces the elemental/isotopic fractionation, and enhances the sensitivity of the measurements. Many researches have shown that femtosecond laser pulsing brings these benefits to LA-ICP-MS analysis:

• Non-thermal mass ablation such as Coulomb explosion and direct chemical bond breaking that represents the true chemistry of the sample and is conducive in reducing the elemental/isotopic fractionation.
• An ideal size distribution (20 ~ 200 nm) of the ablated particles that are readily transported to the ICP-MS plasma torch that result in the increased detection sensitivity.
• More consistent size distribution of the ablated particles that decrease the fluctuations in the transient ICP-MS signal and increase the measurement precision.
• Complete digestion of the transported particles and reduction of fractionation in the secondary excitation source of the ICP-MS instrument.

Applied Spectra harnesses LIBS technology with its state-of-the-art elemental testing devices. We deliver solutions that are fast, reliable, precise and environmentally friendly. Our instruments are adaptable to a variety of environments, from field testing, to manufacturing floors, to laboratory settings. Contact ASI’s technical sales staff to learn more.

[1] R.E. Russo, X.L. Mao, H.C. Liu, J.H. Yoo, S.S. Mao: Appl. Phys. A 69 [Suppl.], S887–S894 (1999)