RESOLUTION AND SENSITIVITY IN ORGANIC CHEMICAL MASS SPECTROGRAPHY

The capabilities of high resolution mass spectrography using llford Q2 and Technical Operations evaporated AgBr photographic plates as ion detectors are discussed. The minimum line width attainable with Q2 plates is found to be 2 to 3 n and the effects of instrument parameters on line width are given. For m/e > 200, the dependence of Q2 plate sensitivity on ion mass can be summarized by the function D = 3.0 + 0.25 log10 ( 1000 ρ/m1.2); where D = optical density of the blackened photoplate; ρ = charge density of exposing ions at surface of plate, C/mm2; and m = mass of exposing ions. The sensitivity of the evaporated AgBr plates is independent of mass, but these plates have very slight exposure latitude. It is calculated that because of mass and energy effects samples as large as 0.1 mg will be required for the photoplate recording of complete high resolution mass spectra of compounds with molecular weight ~ 1750. © 1969, American Chemical Society. All rights reserved.