Abstract: An apparatus for use in determining the presence and/or concentration of one or more selected materials in a matrix stream of materials within a process pipe, reactor or other process vessel, including (a) a support member having a first, internal end for inserting into the matrix stream when the apparatus is placed in service and a second end positioned externally of the pipe, reactor or other vessel in use, wherein the support member defines a groove therein of which at least a portion extends into the matrix stream in use, and (b) a conduit, for example a capillary membrane, positioned and supported substantially wholly within at least that portion of the groove in the support member which extends into the matrix stream in use.

Abstract: A method for titration flow injection analysis by introducing a multicomponent sample into a carrier stream which flows into a mixing/sensing cell and titrating with a reactant more than one component of the sample by sensing a plurality of endpoints. The apparatus of the invention includes a stirring means within the mixing/sensing cell which generates helical flow within the cell so that bubbles are not retained in the cell.

Abstract: The present invention provides an electrolyte solution, a reference half-cell, and a complete electrochemical cell particularly useful in making pH measurements of industrial and waste streams having suspended solids or high salt concentrations. An electrolyte solution containing water; at least one lithium salt, e.g. lithium chloride; and at least one ionic species at a constant electrochemical potential, e.g. silver chloride, buffered to a constant pH, is used in the half-cell and complete electrochemical cell. A high concentration of total ions in the electrolyte solution provides a flow direction out of the cell into the test stream, thereby reducing or eliminating the problems of cell contamination and plugging previously encountered. A second solution of high total ionic concentration, e.g. lithium nitrate, is also provided as a salt bridge in the cells to further insure diffusion of the cell electrolyte solution out into the stream being tested.

Abstract: A method for titration flow injection analysis by introducing a multicomponent sample into a carrier stream which flows into a mixing/sensing cell and titrating with a reactant more than one component of the sample by sensing a plurality of endpoints. The apparatus of the invention includes a stirring means within the mixing/sensing cell which generates helical flow within the cell so that bubbles are not retained in the cell.

Abstract: A method for electrolytically pretreating a cation exchange membrane by partitioning a first aqueous electrolyte solution from a second aqueous electrolyte solution with the membrane and then passing an electrical current through the system so that the cations of the first solution electro-migrate through the membrane into the second solution. The cation composition of the first solution being more than 99.99% of hydrogen ion and a single cation moiety selected from the group consisting of alkali metal cations and alkaline earth cations, the cation composition of the second solution consisting essentially of the same cation composition as the first solution. The result is a membrane that is almost completely equilibrated with the cations of the first solution. The pretreated membrane is especially suitable for use in the sensor for chemical analysis described in U.S. Pat. No. 4,333,810.

Abstract: This invention provides a calibration unit for generating known concentrations of an oxidizing or a reducing gas in an inert carrier gas. THe gas-generating electrode is sandwiched between an ion-exchange membrane and a porous diffusion membrane for minimizing the liquid layer thickness around the electrode and for regularizing the rate of diffusion of the gas generated. The present invention is especially useful for calibrating gas sensors which detect, measure, and monitor the concentration of a gas in the atmosphere, and for providing an accurate low concentration of gas for use wherever desired.

Abstract: An analyzer for the quantitative determination of a chemical oxidizing or reducing agent in a fluid environment. The analyzer includes a novel type of sensor or detector comprising a first electrode exposed to the fluid environment; a second electrode in contact with a solution of electrolyte; and an ion-exchange membrane to contain the electrolyte solution, and to separate the second electrode from the fluid environment and the first electrode.