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Formation of multiply charged ions from large molecules using massive-cluster impact
J F Mahoney1, D S Cornett, T D Lee
1Phrasor Scientific Inc., Duarte, California 91010.
Rapid Communications in Mass Spectrometry : RCM
|May 1, 1994
Summary
Massive-cluster impact effectively analyzes large proteins up to 17 kDa. This mass spectrometry technique reduces chemical background and enhances detectable mass range through multiply charged ions.
Area of Science:
- Analytical Chemistry
- Biophysics
Background:
- Conventional ionization techniques in mass spectrometry face limitations in analyzing large proteins.
- The need for sensitive and effective ionization methods for biomolecules is critical.
Purpose of the Study:
- To evaluate massive-cluster impact as an ionization technique for mass analysis of large proteins.
- To assess the compatibility of the cluster source with different mass spectrometers.
- To characterize the resulting mass spectra, focusing on charge states and background noise.
Main Methods:
- Utilized massive-cluster impact for ionization of proteins.
- Coupled the cluster source to magnetic-sector and quadrupole mass spectrometers.
- Analyzed mass spectra of proteins, including chicken egg lysozyme (14,310 Da), in a 100% glycerol matrix.
Main Results:
- Massive-cluster impact successfully ionized proteins up to 17 kDa.
- Mass spectra exhibited minimal chemical background.
- A predominance of multiply charged ions (ranging from +3 to +9 for lysozyme) was observed.
- Higher charge states facilitated analysis of lower m/z values, extending the effective mass range.
Conclusions:
- Massive-cluster impact is a viable and effective ionization method for large protein mass spectrometry.
- The technique offers advantages over conventional methods by reducing background and increasing the detectable mass range.
- The cluster source's design allows for versatile application with common mass spectrometer types.