Abstract: A radioactivity measuring instrument, and a method related to its use, for determining the radioactivity of a sample measured in the presence of significant background radiation, and for determining an error value relating to a specific probability of accuracy of the result. Error values relating to the measurement of background radiation alone, and to the measurement of sample radiation and background radiation together, are combined to produce a true error value relating to the sample radiation alone.

Abstract: A standard for calibrating a densitometer or the like is disclosed consisting of an optically transparent substrate supporting a plurality of spaced bands of different predetermined optical densities. Each band comprises alternate dark and clear strips and is sized to eclipse a beam of light generated in the densitometer and defining an illuminated zone. The width of the clear strips is large compared to the wavelength of the light beam and small compared to the width of the illuminated zone so that the quantities of light passing through the bands as the standard moves through the densitometer, and hence the optical densities of the bands, are directly proportional to the ratio of the areas of the clear strips to the areas of the dark strips in the bands. The bands are placed at an angle to the scan axis of the illuminated zone to present a gradient change in optical density to a scanning densitometer which is within the response time thereof.

Abstract: Apparatus is disclosed for accomplishing electrophoresis in an automated manner. A supported electrophoretic medium, having been implanted with sample to be analyzed, is moved through a chamber wherein the electrophoresis takes place. The apparatus comprises an electrophoresis separation chamber containing a pair of elongated electrolyte wells, electrolyte contained within the wells, electrodes disposed within the electrolyte and connectable to an appropriate source of power, and a wicking arrangement communicating with each of the electrolyte wells to provide a continuous electrical contact zone.

Abstract: Titration apparatus for measuring chloride electrolyte in blood samples including a pair of coulometric generator electrodes for titrating the chloride with silver ions to precipitate silver chloride and a pair of amperometric detector electrodes for detecting completion of the silver chloride precipitation. The amperometric electrodes and one of the coulometric electrodes (cathode) are contained in a unitary electrode module which is mounted separately from the remaining coulometric electrode (anode) and which is readily removable for cleaning.