VAMAS interlaboratory study for desorption electrospray ionization mass spectrometry (DESI MS) intensity...

Area of Science:

• Analytical Chemistry
• Mass Spectrometry

Background:

• The Versailles Project on Advanced Materials and Standards (VAMAS) coordinated an interlaboratory study.
• Desorption electrospray ionization mass spectrometry (DESI MS) is a surface analysis technique.
• Standardized protocols are crucial for reliable interlaboratory comparisons.

Purpose of the Study:

• To evaluate the repeatability of DESI MS measurements across multiple laboratories.
• To assess the suitability of Rhodamine B and adhesive tape as reference materials for DESI MS.
• To identify factors affecting measurement variability and propose improvements.

Main Methods:

• Twenty laboratories from ten countries participated in the study.
• Participants followed a provided analytical protocol for DESI MS.
• Reference samples included Rhodamine B and adhesive tape on glass slides.
• Positive ion mass spectra were acquired in predetermined m/z ranges.

Main Results:

• Rhodamine B demonstrated consistent crater generation but variable shapes due to instrument design.
• Average repeatability for Rhodamine B was 50%, with potential for <20% under optimal conditions.
• Adhesive tape showed average absolute intensity repeatability of 30% and relative repeatability of 9%.
• Day-to-day variations were attributed to adventitious adducts and contaminants, impacting relative intensity constancy.

Conclusions:

• Rhodamine B is a suitable reference material for evaluating DESI MS performance metrics.
• Instrument design and sample handling significantly influence measurement repeatability.
• Controlling solvent composition, e.g., adding sodium, can mitigate day-to-day variations and improve repeatability to <5%.