7 Tips for Better Sample Prep in LIBS Analysis (with Video!)

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LIBS technology (Laser Induced Breakdown Spectroscopy) can be utilised to help accurately and repeatedly capture carbon content as well as automatically calculate carbon equivalency using a prescribed formula via pseudo element feature.

A handheld LIBS analyser fires a pulsed laser at the sample vaporising the material to form a plasma on the surface with ~200 pulses per reading.  Excited electrons return to ground state in atoms and ions, emitting light which is collected by on-board spectrometers. The instrument’s software and calibrations compare the wavelengths and intensity of spectral lines to quantify the concentrations of elements, and using a prescribed formula via a pseudo element feature, enables automatic calculation of carbon equivalency.

Sample preparation is very important to LIBS analysis and must be performed before any measurement process to ensure the most reliable performance and results.  Here are seven tips to follow for better sample preparation and more accurate analysis when using a handheld LIBS analyser:

  1. Choose an acceptable test location by avoiding areas of heavy pitting or grinding on critical dimensions, such as, flange faces, shaft journals or over markings (heat, lot numbers, etc…).
  2. Confirming adequate material thickness is a good practice prior to preparation of in-situ pressure containing components, such as process piping.
  3. Consider material composition and grit when selecting abrasive grinding media. 60-80 grit zirconium aluminium oxide is recommended for typical carbon and low allow steels. Avoid using silicon carbide.
  4. Work the sanding disc near parallel to the surface evenly to produce a ~1”x1” area for easy positioning.
  5. Avoid using excessive pressure while maintaining positive control to avoid dishing or removing excessive material.
  6. Remove, replace and discard used discs often.
  7. Follow safety procedures. Be aware of spark/ debris discharge direction and wear personal protective equipment (PPE) as appropriate.

Want to see what good sample prep looks like?
Here’s a video showing best practices for sample preparation before performing a LIBS analysis with a handheld analyser.

For more information:

FAQs – Niton Apollo Handheld LIBS Analyser
Low Alloy / Carbon Steel Library Technical Reference Sheet
How Does LIBS Work?
Handheld XRF & LIBS Safety Training

Source: Thermo Fisher Scientific – Analyzing Metals

Blog, LIBS