An apparatus for imaging an object on an electrooptical transducer for measuring the transparency and/or the light dispersion of the object comprises a light source, a first beam path for illuminating the object and a second beam path for imaging the object on the electrooptical transducer. Furthermore, a third beam path is provided which forms a reference beam path and which conducts part of the light of the first beam path onto the same electrooptical transducer.

A method and apparatus for increasing detector sensitivity in a Capillary Zone Electrophoresis detector is disclosed. The present invention employs a unique cell, fabricated directly into a separations capillary, that increases both the flux and the path length of the ultra-violet light employed in an absorption measurement. The cell employs controlled geometric contours and osmotic pumping to prevent laminar mixing and turbulence. This novel design maintains the resolution of the parent biological separations instrument, while affording an order of magnitude enhancement of in sensitivity. A narrow bore capillary includes an injection end and an output end. Each end is placed in a reservoir containing a buffer solution and a sample of solute. The solute comprises at least one unknown constituent component. An electric field is imposed across the buffer solution and solute in the capillary by a power supply coupled to leads and electrodes. A source of ultraviolet light illuminates a novel cell within the capillary and a sensor measures the absorbance of radiation by the solute to detect the constituent components. A computer may be coupled to absorbance detection circuitry to analyze and display the results of the identification procedure.

An analyzer for electrophoretic samples has a sample stage movable linearly with respect to a source and a detector of analysis energy. During a first scan of the sample, a voltage is produced representing either the minimum detected fluorescence or the minimum detected optical density. During a second scan, the voltage is combined with the output of the detector to automatically correct the output to a reference.

An electrically operated recording measuring instrument burns out the trace of a curve on a moving record medium coated on both sides with an evaporated metal layer. The power supply for the burnout current also feeds an auxiliary writing member for burning out an additional trace to isolate an area of the metal layer under the curve and, if desired, to subdivide the area in a similar way. The power supply also furnishes a higher voltage to a test probe for burning out any remaining conducting bridges across the burnout traces before capacitance measurements are made which can read directly in terms of area or relative area. The method and apparatus are particularly usable for photoelectrically evaluating blood samples treated by electrophoresis to separate the proteins.

Multiple electropherograms or chromatograms representing successive stages of an electrophoretic or chromatographic separation in a capillary are obtained by training a recorder on a succession of detection windows in the capillary, spaced apart along the capillary length. A single immovable detector is used, and the capillary is either held such that each detection window is placed in alignment with the detector in succession, or is looped such that the detection windows all lie in the path of the detector at the same time.