Abstract: Various methods are described for producing volumetric one-component iodine-free Karl Fischer reagents useful for determining the water content of a sample, the reagents containing triiodide as the dominant oxidizing species. The reagents contain a reducing agent such as SO.sub.2, a buffer such as amine, a solvent, and an oxidizing agent that is triiodide, generally in the form of triiodide ions. The molar amount of SO.sub.2 in these reagents is greater than the molar amount of triiodide. The characteristics of these methods generally include the formation of triiodide in a first solution having a first amine/SO.sub.2 ratio prior to obtaining a final solution having the final amine/SO.sub.2 ratio. These methods provide economies in the ingredients used, and yield reagents exhibiting good liter strength and enhanced reproducibility of properties from one production run to the next.

Abstract: An essentially iodine-free and pyridine-free single component reagent for volumetric water analysis using the Karl Fischer reaction, a process for making the reagent, and the use of the reagent to determine the water content of a sample. The reagent contains triiodide ions as an oxidizing agent, a buffer such as an amine, a reducing agent such as SO.sub.2, and a solvent. The presence of iodine, if any, is in an amount less than 1% of the amount of the triiodide ions.

Abstract: A high current coulometric titrator for the Karl Fischer determination of water in which a diaphragm is not required between the electrodes of the iodine-generating circuit. These electrodes are designed to ensure that substantially only iodine is generated at the anode while minimizing conversion of iodine to iodide at the cathode. In a preferred embodiment, the anode has a generally curved shape, all portions of which are substantially equidistant from the cathode. Increased current efficiency results wherein the amount of iodine generated at the anode increases as the magnitude of the iodine-generating current increases. Titration rates in excess of 2.5 milligrams of water per minute are achieved.

Abstract: An improved technique and apparatus for automatic titration for determining the water content of a sample by a Karl Fischer (K.F.) reaction. Rather than requiring titration from one endpoint to another identical endpoint, each determination is made using a calibration relative to the water equivalent of a known amount of titrant together with the change in sensor output that occurs when a sample is added to the K.F. reagent. Improved accuracy and speed of analysis results.

Abstract: An improved K.F. solution for colorimetric analysis to determine the water content of an unknown sample, and an improved sealed vial or ampule containing this solution and a process for determining water content using this solution and the sealed vial. The ampule is designed so that it can be broken into discrete parts, where an air-tight seal is maintained by the presence of an elastic band located in the area where the vial is broken. A syringe needle is used to pierce the elastic band to inject a precisely controlled amount of unknown sample into the vial. The K.F. solution is optimally comprised of a reducing ion such as SO.sub.2, a buffer including imidazole or its derivatives, iodine, iodide, and a solvent which can include a halogenated hydrocarbon.

Abstract: A method for the colorimetric determination of water content of an unknown sample, using the Karl Fischer reaction. The Karl Fischer reagent in a container has added to it a dye whose optical absorption preferably does not overlap with the optical absorption of the Karl Fischer reagent. Measurement of the optical absorption of the reagent/dye mixture is then made at two wavelengths, one wavelength being strongly absorbed by iodine in the reagent while the other wavelength is strongly absorbed by the dye. After the unknown sample is added, optical absorption measurements are again made at the two wavelengths. The measurements made at the wavelength where the dye strongly absorbs are used to correct the optical absorption measurements made at the wavelength where iodine strongly absorbs. This corrects for all factors affecting optical density other than the amount of water in the unknown sample.

Abstract: Improved Karl Fischer reagents of the two-component type are described which eliminate problems such as inaccurate results and false end-points during titrations to determine the water content of a sample. The two-component reagent includes a vessel solution and a titrant solution, where the sample is added to the vessel solution and is titrated with the titrant in order to determine the water content of the sample. The improved vessel solution is one containing an amine such as diethanolamine or imidazole, a reducing ion such as SO.sub.2, alcohol, and iodide in an amount between 0.002 and 0.4 mol/liter. The titrant is an iodine-containing solution.

Abstract: An improved method and reagent for determining the water content of a sample using a Karl Fischer type of reaction. The sample to be tested is placed in a vessel with a Karl Fischer type reagent. A known amount of a new titrant is then added to determine the water content of the sample, the new titrant including, preferably, only a halogen (such as iodine) and a solvent having high solubility for the halogen but very low solubility for water. An example of such a titrant solvent is xylene. The titrant is not affected by the presence of moisture in the atmosphere and does not lose its strength over prolonged periods of time. Because the reactions between the various constituents of the vessel solution-sample mixture and the titrant occur rapidly, the endpoint of the Karl Fischer reaction is much sharper than with the use of prior art reagents.

Abstract: A thermostat range control device for maintaining a thermostat temperature that has a substantially constant difference with respect to room temperature, and which allows the thermostat to respond quickly and accurately to changes in room temperature. The device includes a detachable enclosure for substantially enclosing the thermostat, a distributed heater within the enclosure having multiple openings therein for providing generally uniform heat within the enclosure, means for allowing room temperature air to enter the enclosure at a level below the thermostat, and means for allowing heated air within the enclosure to exit from the enclosure at a level above the thermostat, in a manner such that substantially only heated air passes the thermostat.

Abstract: A plate for use in electrophoresis, comprising a membrane coated with a layer of an electrophoretic medium such as agarose gel. The membrane is bonded to a supporting sheet having cutouts in which the electrophoresis is performed. A transport apparatus moves the plates through an electrophoresis bath into an optical scanning densitometer.

Abstract: A method and apparatus for zone electrophoresis which is completely automatic and which requires no manual handling of the electrophoretic medium or the serum sample to be tested. In a preferred embodiment, prefabricated (empty) electrophoresis tubes are placed into a turntable. An automatic diluter then loads, in one operation, known amounts of sample serum and the electrophoretic medium into the tubes. Electrophoretic separation is then achieved automatically by application of a suitable voltage. The electrophoretic pattern produced in the tube is then measured by an optical probe which is dipped into the tube without disturbing the electrophoretic pattern established therein. This probe moves through the electrophoretic medium and measures the pattern quantitatively. This measurement can be directly transmitted to utilization equipment, such as data processing apparatus.

Abstract: A plate for use in electrophoresis, comprising a membrane coated with a layer of an electrophoretic medium such as agarose gel. The membrane is bonded to a supporting sheet having cutouts in which the electrophoresis is performed. A transport apparatus moves the plates through an electrophoresis bath into an optical scanning densitometer.

Abstract: An improved apparatus and method for detecting CO.sub.2 and Cl.sup.- in body fluids, such as whole blood, blood serum and plasma, etc. A reagent and a known amount of the sample to be tested react in a vessel to release CO.sub.2 into a gas space. The released gas is then displaced to a detector where its concentration in a substantially stationary gas sample is measured. After both CO.sub.2 and Cl.sup.- have been measured, the mixture of sample, reagent, and gas is then drained from the vessel and from the detector and a reverse flow of excess flushing fluid (gas) is moved through the detector and the vessel to flush the apparatus so that another measurement can begin. After each measurement, the instrument is zeroed. In the practice of the present invention, the zeroing operation is more accurate when the flushing gas is equilibrated with the reagent solution, i.e., when the air used for flushing has picked up some of the vapors of the reagent solution.

Abstract: Reagent compositions for use in CO.sub.2 analysis which comprise certain acids and/or buffered acids together with selected additives. The acids and buffered acids have pH less than 4 and a vapor pressure not in excess of 10mm mercury. Examples of these acids include lactic acid, citric acid, phosphoric acid, sulfuric acid, perchloric acid, malic acid, malonic acid, oxalic acid, naphthalenesulfonic acid, picric acid, sulfamic acid, and nitric acid. The additives, which can be used separately or with one another, are ethers of fatty alcohols and polyoxyethylene (having the structure R--O--(C.sub.2 H.sub.4 --O).sub.n H), glycerin, polyvinyl alcohol, and pH sensitive indicator dyes, including methyl red, p-nitrophenol, neutral red, phenolphthalein, and o-cresolphthalein. An improved method for analysis of CO.sub.2 in body fluids comprises the steps of adding these reagents to body fluid samples to release CO.sub.2 therefrom into a gas space, displacing the released CO.sub.

Abstract: A colorimetric test for water in a vial which is prepacked with Karl-Fischer-Reagent and a colorimeter for direct readout of water content.

Abstract: A method and apparatus for measuring CO.sub.2, O.sub.2 and chlorides in body fluids, such as whole blood, blood serum and plasma, etc. A reagent and a known amount of sample to be tested react in a closed vessel to release the gas to be measured into a gas space. A displacement liquid is then introduced to expel the released gas in the gas space to a detector, where its concentration in a stationary gas sample is measured. The mixture of sample, reagent, and gas is then drained from the vessel and from the detector and a reverse flow of excess flushing fluid (gas) is moved through the detector and vessel to flush the apparatus so that another measurement can begin.