Modification of Wiley-Mclaren Tof Analyzers for Laser Desorption

Abstract

Conversion of Wiley-McLaren type TOF instruments for laser desorption is described, including laser optics, timing circuitry, postacceleration detection for high mass and data acquisition. Results are shown to illustrate signal averaging capabilties, detection limits and high mass measurements. 93 Copyright© 1987 bv Marcel rvn-er i--Downloaded by [Nanyang Technological University] at 19:48 07 June 2016 94 OLTHOFF ET AL.

Ultraviolet laser desorption/ionization mass spectrometry of proteins above 100,000 daltons by pulsed ion extraction time-of-flight analysis

“…The instrument configuration used for the experiments reported here is much the same as that employed previously for IR laser desorption (16) and has been described in detail earlier (19). However, several modifications were made to enable desorption ionization of large proteins.…”

Desorption of ions from rat membranes: Selectivity of different ionization techniques

“…This configuration has been described earlier. [32][33] Liquid secondary ion mass spectra were obtained on a time-of-flight mass spectrometer designed and fabricated in our l a b~r a t o r y .~~,~~ This instrument is equipped with a Kratos (Ramsey, New Jersey) Minibeam I rare gas ion gun and a Galileo (Sturbridge, Massachusetts) dual channelplate detector floated at + I 2 kV to provide post-acceleration of the secondary ions. Analog spectra are recorded and digitized by a LeCroy (Spring Valley, New York) 3500SA 100 MHz waveform recorder and signal averager.…”

Laser desorption from a probe in the cavity of a quadrupole ion storage mass spectrometer

“…The laser spot was focused off-center on the probe tip so that rotation of the probe would continually present fresh surfaces for irradiation. Pulse energies could be varied by opening or closing the laser exit aperture, but operating conditions were basically the same as for LD time-of-flight (LD-TOF) mass spectra obtained previously in this laboratory (11), where power density was approximately 106 W / cm2. Sample preparation was the same in all cases.…”