GB1484742A - Mass spectrometric system for rapid automatic and specific identification and quantification of compounds - Google Patents

Abstract

1484742 Mass spectrometers UNIVERSAL MONITOR CORP 6 May 1975 [16 May 1974] 19001/75 Heading HID A mass spectrometer system includes a data analysing system which stores spectral data of known substances being sought and which also stores criteria for judging the presence of these substances (e.g. detection of a certain number of spectral lines typifying a substance): output signals from the mass spectrometer are compared with the stored spectral data and on the basis of the said criteria an indication is given of the presence or absence of substances sought. The presence or absence of a substance can be judged on a probabilistic basis and an indication of confidence in the result can be given. The likelihood of finding a particular line at random can be taken into account. The intensity of spectral lines can be measured to give a quantitative estimate of a substance. The substances sought can be organized in sets and the determination can be based on these sets rather than individual substances. The Specification describes in detail and at some length the various elements of the spectrometer system. The main items described are as follows (none of the Figures is shown here): Figs. 2a and 2b means for injecting samples in a neutral gas into the spectrometer; Figs. 3 and 4 a quadrupole mass spectrometer and a control system and power supply therefor; Fig. 5 a variable gain detector amplifier; Fig. 6 a "peak stretcher" circuit which stores the maximum detector amplifier output in any spectrometer scan; Fig. 7 a block diagram of the analysing system which can be a suitably programmed digital computer and Fig. 8 illustrates a "contracted spectrum" which can be stored in the analysing system this spectrum consisting of selected lines of the full spectrum.