Abstract: Novel nitroaromatic compounds and immunogenic conjugates comprising a novel nitroaromatic compound and a carrier protein are disclosed. The invention further presents monoclonal antibodies highly specific for the claimed nitroaromatic compounds, the compounds' protein conjugates, the compounds' reductive byproducts, and adducts formed between the compounds and mammalian hypoxic cell tissue proteins. The invention is further directed to methods for detecting tissue hypoxia using immunohistological techniques, non-invasive nuclear medicinal methods, or nuclear magnetic resonance. Diagnostic kits useful in practicing the methods of claimed invention are also provided.

Abstract: A mass spectrometry system comprises a source of ions for analysis, an ion storage device for separating the source ions as a function of their different mass-to-charge ratios, means for dissociating the separated source ions in order to generate daughter ions and an ion mirror for analyzing the daughter ions as a function of the mass-to-charge ratios. The mass spectrometry system has particular utility in the analysis of large molecules contained in biological and biochemical samples.

Abstract: In the magnetic analyzer of a mass spectrometer in which a beam of ions travels from an entry slit to a collector slit, the field strength of the electromagnet can be increased by reducing the flux gap. In order however to avoid impingement of ions against the wall portions of the spectrometer tube in the reduced flux gap without reducing the width of the beam, collimating means are provided at opposite ends of the wall portions in the gap, the opposite walls of the collimating means extending from the tube wall portions up to the beam to intercept ions which otherwise would enter the collector slit directly or after reflection from the wall portions.

Abstract: Ions are formed from an unknown substance in a first ion source of a double beam mass spectrometer and accelerated therefrom at a low accelerating voltage, e.g. 1kV or 2kV. Ions are formed from a reference substance in the second ion source and accelerated therefrom at a relatively high accelerating voltage, e.g. 8kV. The ion beams so formed pass through a common magnetic analyser to produce respective mass spectra. With pefluorokerosene as a reference substance producing a reference mass scale up to about 1000a.m.u., the mass spectrum of the unknown substance can be accurately calibrated (mass marked) up to 8000a.m.u. or 4000a.m.u. (with the above exemplary low accelerating voltages). Thus the invention enables the inherently very accurate chemical mass marking ability of a double-beam mass spectrometer to be scaled up along the mass scale of the unknown substance.