De. Schilke et Rj. Levis, A LASER VAPORIZATION, LASER IONIZATION TIME-OF-FLIGHT MASS-SPECTROMETER FOR THE PROBING OF FRAGILE BIOMOLECULES, Review of scientific instruments, 65(6), 1994, pp. 1903-1911
We report the design and evaluation of a new spectrometer for probing
fragile biomolecules in the gas phase. The spectrometer is based on a
laser vaporization method to transfer biomolecules up to several hundr
ed thousand dalton into the gas phase as intact, neutral species. This
method requires the formation of a thin film containing a dye molecul
e and the analyte of interest which is molecularly vaporized using a h
igh energy, pulsed laser. The gas phase, neutral analyte molecules are
laser vaporized directly into a laser ionization region without the n
eed of a pulsed nozzle. The molecules are subsequently ionized using m
ultiphoton ionization; two-color, two-photon laser ionization is repor
ted here. The resulting ions are detected using time-of-flight mass sp
ectrometry. The spectrometer employs a four grid extraction system whi
ch both filters unwanted ions produced in the initial vaporization ste
p and extracts the laser ionized species into the field free drift reg
ion. A hybrid copper-beryllium dynode with a dual microchannel plate d
etector is employed as the high mass ion detector and amplifier before
external amplification. Anthracene-tagged nucleotides and some small
test molecules are vaporized and ionized to evaluate the spectrometer.