Mass Spectrometer for High Molecular Weight Ions and Charged Particles
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Mass Spectrometer for High Molecular Weight Ions and Charged Particles



  • Biotechnology
  • Structural biology
  • Materials science studies of nanoparticles


  • Measures mass of large ions faster and more accurately than gel electrophoresis without the need for calibration standards


Berkeley Lab researchers have developed a spectrometer capable of measuring the mass and velocity of large molecular ions and charged particles. Berkeley Lab's mass spectrometer measures the mass of large ions more quickly and accurately than gel electrophoresis, which presently is the only competing method capable of analyzing large ion masses.

A highly sensitive charge-measuring amplifier determines the charge and velocity of individual ions, providing they carry more than about 200 charges, as they fly through a small metal detector tube. Ion mass is calculated directly from these measurements and knowledge of ion energy.The system measures individual ions; mass spectra are acquired by measuring a few thousand ions.

Berkeley Lab's new spectrometer also features a switchable electric field for reflecting ions or charged particles so they travel back and forth through the detector tube. This unique feature provides a way to measure charge and velocity of single ions or particles repeatedly, thus statistically improving the precision of these measurements.

The current system has been designed for measuring ion masses exceeding about 750,000 Daltons or particles larger than about 1 x 10 - 18 grams, carrying the requisite 200 charges. Berkeley Lab's new mass spectrometer has accurately sized DNA molecules and aerosol particles. Potentially, the mass spectrometer could also be used for weighing virus particles, organelles and large macromolecular complexes. The newly emerging field of structural biology, and the materials area of nanoparticles might also find applications for this novel instrument.

STATUS: U.S. Patent # 5,770,857. Available for licensing