First Signal!

First Signal Achieved on the Cryogenic FTMS!

Peter B. O’Connor, Cheng Lin, Raman Mathur, Konstantine Aizikov

May 18, 2007, Boston University School of Medicine

The Cryogenic MALDI-FTMS being developed at the Cardiovascular Proteomics Center (CPC) at Boston University School of Medicine has finally achieved first signal. This instrument design was first conceived November 2001, published mid 2002, and funded by the National Institutes of Health, National Heart Lung and Blood Institute as the major instrument development project of the CPC starting October 2002.

The Cryogenic MALDI-FTMS is a major advance in FTICR mass spectrometry design. It involves close construction and integration of the FTICR with a modern cryogenic superconducting magnet design. Doing so provides three major advantages. First, the magnet bore and FTICR cell chamber becomes very cold, which cryopumps the chamber and decreases the base pressure. Second, because of the cryopumping, the bore tube diameter can be made much smaller, allowing high homogeneity and high magnetic fields to be generated at greatly reduced cost. Third, the cold surfaces can be used to cool a preamplifier for improved signal/noise. The current instrument is designed with a 14 Tesla magnet at ~10 ppm homogeneity over the 2”x2” cylindrical ICR cell. As such, this instrument, when fully tuned in, will provide several orders of magnitude better performance than existing instruments with a parts cost ~2x lower and a magnet cost ~4x lower.

The first signal (Figure 1 top) is C60 laser desorbed, transferred down the two hexapoles, and detected in the ICR cell. Figure 1 (bottom) shows an optimized signal under the current conditions. While there are many improvements that still need to be made, and the amplifier currently being used is at room temperature outside the vacuum, these figures demonstrate that the instrument functions, and we have signal which can be used to tune the instrument in much better. Figure 2 shows the researchers in front of the instrument.

The bulk of this development project was funded by NIH/NHLBI under contract N01HV28178 with important components funded by NIH/NCRR grant P41RR10888.