Abstract: A device and method for determining the concentration of an analyte, particularly a chloride ion, in a liquid sample are particularly useful to screen for cystic fibrosis in an individual. In a preferred embodiment, the device takes the form of a patch comprising an absorbent material sandwiched between two liquid-impermeable layers. Chloride ions in the liquid sample complex with a chloride-detecting agent dispersed throughout the absorbent material to form a visible precipitate, preferably silver chloride. A pH indicator is also dispersed throughout the absorbent material, allowing the position of the water front to be monitored thereby permitting calculation of chloride concentration from a partially filled patch.
Abstract: A portion a the machine which the operator regularly engages with his or her hands has incorporated therein a plurality of passageways (14) through which a vacuum is applied to draw vapor which is emitted by the hands of the individual. Vapor from the individual's hands is drawn through a sampling apparatus. The sampling apparatus contains an electrical coil (32, 36, 42, 46) which is coated with a composite metal-nonmetal catalytic substance which causes ethanol to oxidize at the coil. When ethanol-containing vapor passes over the coil, oxidation at the coil causes an electrical charge to build up on the coil. The charge build-up is detected and processed in a discriminating type of electrical circuit which incorporates a wheatstone bridge or a constant-current loop. The resulting signal is further processed then ultimately used to estimate the alcohol content of the individual.
April 28, 1998
Date of Patent:
October 19, 1999
Ellwood G. Ivey, Jr., Michael L. Horovitz, Cedric Stratton
Abstract: A method for continuous tracking of blood alcohol, is comprised of 1) a potential- and diffusion-controlled electrochemical solid polymer electrolyte sensor that continuously and concurrently measures very low concentrations of ethanol vapor at the surface of the skin as well as skin properties such as temperature and ionic conductivity, 2) a sensor control circuit, and 3) a data acquisition-recording device. Sensitive and reproducible measurements of ethanol over a wide population range is obtained by simultaneously maintaining the potential of the sensing electrode constant at a voltage above the rest potential of the platinum/air (O.sub.2) electrode and by use of a thin, permselective diffusion-control membrane over the sensing electrode, and in series with the human stratum corneum membrane. The electrochemical oxidation current is a direct measure of the local ethanol vapor concentration over the skin surface.
April 16, 1997
Date of Patent:
August 31, 1999
Larry L. Swette, Arthur E. Griffith, Anthony B. LaConti