What is MALDI?
MALDI (matrix-assisted laser desorption/ionisation) is a mass-spectrometry ionisation method that uses a UV-absorbing crystalline matrix to facilitate laser-driven desorption and ionisation of peptide samples. The alternative ionisation method to electrospray ionisation; produces predominantly singly-charged ions.
What the research literature says
MALDI co-crystallises a peptide sample with a UV-absorbing matrix compound (typically α-cyano-4-hydroxycinnamic acid or sinapinic acid). A pulsed UV laser strikes the crystallised spot, the matrix absorbs the laser energy, vaporises into the gas phase carrying ionised peptide with it, and the resulting peptide ions are extracted into the mass analyser. The technique is gentle — it preserves peptide structure — and produces predominantly singly-charged ions [M+H]⁺, simplifying mass-spectrum interpretation but requiring higher mass-resolution at the analyser stage for larger peptides.
MALDI is typically paired with a time-of-flight (TOF) mass analyser to form the MALDI-TOF instrument configuration. The instrument architecture supports rapid sample analysis but doesn’t couple naturally with liquid-chromatography front-ends — for the combined LC-MS workflow, ESI is the preferred ionisation method.
The USP <1736> general chapter on mass spectrometry covers MALDI and the broader mass-spectrometric methods framework.
Why this matters in research context
MALDI matters in peptide-research contexts as the alternative mass-spectrometry ionisation method to ESI. Researchers reviewing a peptide COA may see either method’s spectrum depending on the vendor’s analytical workflow — both produce valid peptide-identity verification when paired with appropriate mass-analyser resolution and the mass accuracy needed for the target compound.
Related compounds
- Mass spectrometry (glossary entry) — broader analytical methodology
Related research questions
References
- USP <1736> Applications of Mass Spectrometry. United States Pharmacopeia.
- ICH Q2(R1) — Validation of Analytical Procedures: Text and Methodology. International Council for Harmonisation.
Research-questions pages describe research-context use of peptide-research terminology. They do not constitute medical, veterinary, or clinical advice. Every compound in the Ronin catalog is sold strictly for laboratory and research use only.