Large Molecules such as proteins, DNA, RNA, polymers, and other oligomers can be ionized by MALDI or ESI. ESI of large biomolecules typically will produce multiple charge states so even very large samples can be analyzed with no upper mass limit on the mass analyzer. MALDI typically produces singly charged ions so large molecules can be directly observed without deconvolution.
- MALDI large molecule analysis is typically performed on the Bruker AutoFlex MALDI-TOF. A wide selection of solvents and matrices are available for use. As this method typically requires a lot of sample specific method development, instrument training for self-operation and sample experimentation (to determine matrix, additives, and spotting technique) is recommended.
- For ESI large molecule analysis, a variety of instrumentation is available for this application:
- Agilent 6230 TOF (primary)
- Bruker Impact II QqTOF (secondary)
- Bruker timsTOF Pro2 (if IMS is also desired)