Abstract: A discharge ionization detector which comprises with a cylindrical housing wherein is formed a discharge chamber at one end, and wherein is formed an ionization chamber at the other end an aperture connecting the chambers, arc electrodes being located in the discharge chamber, and emitter/collector electrodes being located in the ionization chamber, the latter comprising flat parallel plates, the housing being provided with an inlet into the discharge chamber for delivering discharge gas to the discharge chamber which discharge gas leaves the discharge chamber through the aforementioned aperture, with an inlet into the ionization chamber for delivering sample gas to the ionization chamber, and with an outlet from the ionization chamber for carrying the mixed discharge gas and sample gas out of the ionization chamber. The discharge gas and sample gas mix then pass between the flat parallel emitter/collector plates before leaving the ionization chamber through the outlet.

Abstract: An improvement in analytic instruments which measure liquid properties by optical techniques, the improvement providing an optical path through the liquid under test as low as about 0.1 mm by presence of a flat transparent surface across the optical beam and by flowing a film of the liquid under test down the surface, the depth of the film being the optical path through the liquid.Desirably the surface is normal to the beam, but at an acute angle to horizontal. A matted surface is desirable for spreading high viscosity solvents across the surface.

Abstract: A hot wire miniaturized thermal conductivity detector with a cavity volume less than 50 microliters characterized by a construction which provides for essentially plug flow through a cylindrical cavity. The gas flows tangentially into and out of toroidal passageways presented between axial filament mounts and the cylindrical cell wall so that the gas flow-passage area increases by stages as the gas flows from an inlet into the detector cavity first through the toroidal passageways therein then through the main body thereof. Correspondingly the flow path decreases by stages from the main body into the toroidal passageway then into the outlet.Preferably the passage area increase from inlet to main body is held to less than a five fold increase in area.