Abstract: Embodiments of methods for electrochemical analysis of arsenic are described. In one embodiment, a method includes detecting arsenic (III) by, at least in part, applying electrolytic current to an arsenic compound that has not been reduced with a reducing agent. In another embodiment, a method for electrochemical analysis of arsenic includes detecting arsenic (V) by, at least in part, applying electrolytic current to an arsenic compound that has not been reduced with a reducing agent.

Abstract: Ion transport apparatus (e.g. an electrolytic eluent generator or a suppressor for ion chromatography) in which ions in a first chamber are transported to a liquid in second chamber through a wall comprising an ion exchange bead sealed in a bead seat. The wall is capable of transport ions but of substantially blocking bulk liquid flow.

Abstract: Apparatus and method for detecting current or potential generated in a liquid sample suitable for use in a chromatography or other liquid sample analytical system. One embodiment is an electrolytic ion transfer device with a signal detector in communication with the electrodes of the transfer device. Another is a combination ion transfer device/electrolyte generator. Another substitutes a detector for the ion transfer device in the combination.

Abstract: Ion transport apparatus (e.g. an electrolytic eluent generator or a suppressor for ion chromatography) in which ions in a first chamber are transported to a liquid in second chamber through a wall comprising an ion exchange bead sealed in a bead seat. The wall is capable of transport ions but of substantially blocking bulk liquid flow.

Abstract: In a liquid chromatographic system, removing at least part of a volatile component from the liquid sample stream after separation by flowing it through a volatile component-removal device including a porous wall having a surface coating of a permeable polymer less than 10 ?m thick. A liquid chromatographic system suitable for performing the method. Also, a liquid chromatographic system in which volatile component is removed prior to separation across the same type of membrane or across a membrane made of a copolymer of perfluoro-2,2-dimethyl-1,3-dioxole.

Abstract: In a liquid chromatographic system, removing at least part of a volatile component from the liquid sample stream after separation by flowing it through a volatile component-removal device including a porous wall having a surface coating of a permeable polymer less than 10 ?m thick. A liquid chromatographic system suitable for performing the method. Also, a liquid chromatographic system in which volatile component is removed prior to separation across the same type of membrane or across a membrane made of a copolymer of perfluoro-2,2-dimethyl-1,3-dioxole.

Abstract: A self-monitoring flow-through heater. The heater has a wire inside a tube, and the wire heats and monitors the temperature of a fluid flowing through the tube. The wire has a high specific resistivity and a high temperature coefficient of resistance, so that monitoring the voltage across and/or the current flowing through the wire measures the mean temperature of the wire and of the fluid in the tube.

Abstract: A denuder assembly is adapted for the collection and removal of a gaseous analyte from a sample gas. The denuder includes a housing including an internal cavity, a sample gas inlet fluidly coupled with a sample gas source, a denuder liquid inlet fluidly coupled with a denuder liquid source, a barrier sheet extending across the internal cavity and separating the internal cavity into a liquid reservoir and a gas flow-through channel fluidly coupled with and downstream of the sample gas inlet, and a denuder liquid disposed in the liquid reservoir and permeating the barrier sheet to coat the gas-channel surface of the barrier sheet thereby allowing the denuder liquid on the gas-channel surface to contact the sample gas flowing within the gas flow-through channel and allowing the analyte to diffuse through the barrier sheet into the liquid reservoir.

Abstract: A sensor having a tubular optical cell or similar structure with a membrane wall. The wall may be permeable so that analyte can enter into the tube containing a reagent. Conversely, the wall structure could instead operate to let reagent enter into the tube containing the analyte. Attached to one end of the tube may be a reagent reservoir. A valve may be attached to the other end of the tube and to a reagent disposal container. The flow or replacement of the reagent in the tube may be caused by gravity, a pump, elastic reservoir design or pressurized gas. One or more light sources may be positioned at one end of the tube with a light detector at the other end. Processing and display electronics may be connected to the valve, light sources and detector.

Abstract: Packings or equivalent structures which produce radial mixing in channels can be used to enhance reagent addition devices for ion chromatography post column reactions in which band spreading at detrimental levels is effectively controlled. Application to two dimensional conductometric detection in simultaneous suppressed and nonsuppressed ion chromatography.

Abstract: Continuous on-line titrations based on feedback-controlled flow and the principle of compensating errors are carried out in a titration system by maintaining a constant total flow of mixed sample and titrant. The flow of the titrant is varied in response to a controller output voltage, and accordingly, the makeup sample flow also varies but inversely to the titrant flow. A detector monitors the status of the indicator color in the mixed stream.

Abstract: A concentrator and sensor assembly are disclosed that use phased heaters to multiply the concentration levels that can be eluted, relative to operation with a single interactive element having a sorbent material to increase the concentration of desired gas constituents at a detector. This is accomplished here by providing two or more interactive concentrator elements that are selectively heated in a time phased sequence so that each of the interactive elements becomes heated and desorbs gas constituents into the sample fluid stream at substantially the same time that an upstream concentration pulse, produced by heating one or more upstream interactive elements, reaches the interactive element. This produces a multiplication effect that significantly increases the concentration of the gas constituents at the detector, thereby increasing the effective sensitivity of the detector.

Abstract: A luminescence detector with a liquid-core waveguide. For detecting photoluminescence, the exciting radiation is provided transversely instead of axially, thus eliminating the need for monochromators and focusing optics. For detecting chemiluminescence, the chemiluminescent reagents are mixed in situ in the detector, thus eliminating time loss which results in loss of chemiluminescence. A further aspect of the invention is the electrogeneration of an unstable reagent for the production of chemiluminescence. The unstable reagent is generated in such a way that there is complete separation of anodic and cathodic products without the use of a physical barrier.

Abstract: A chemical analysis method for the determination of a base (or an acid) in a nonaqueous liquid (such as a polyol) which method can be automated and placed on-line in a chemical production facility. The instant invention includes two steps. The first step is to mix an acid-base indicator (for example, bromocresol green) with the non-aqueous liquid to produce a colored reaction product between the base or acid and the acid-base indicator. The second step is to determine the intensity of the color of the colored product.

Abstract: A capillary electrophoresis system (10) comprising: a separation capillary (20) with a first distal tip (30) and a second distal tip (140); a source vessel (50) containing a solution (40); a microreservoir-electrode (59) comprising a wire loop; a power source (60) connected to the microreservoir-electrode by wire (57); a control system (200); a detector (90); and a final destination vessel (160) containing electrolyte (150) and a ground electrode (155).

Abstract: A permeable optical fiber waveguide with a liquid core is employed as a probe for the detection or measurement of a chemical specie of interest by filling the waveguide core region with a light transmitting reagent liquid which undergoes a change in an optical characteristic thereof when exposed to the chemical specie and then inserting the filled waveguide into an environment in which the chemical specie may be present. The chemical specie, if present, will permeate through the waveguide wall and react with or be absorbed in the core liquid.

Abstract: Direct measurement of soluble ionogenic atmospheric gases is implemented using a suppressed conductometric capillary electrophoresis separation system. A small circular wire loop is incorporated adjacent sampling end of a fused silica capillary, in the same plane as the capillary. Dipping the loop into a solution and then withdrawing forms a liquid film that is in fluid communication with the capillary and acts as a microreservoir. Elevating the film relative to the destination side injects part or all of the film contents into the capillary. This mechanism may be used to perform gas sampling in automated fashion with slightly modified commercial CE instrumentation. The film-bearing loop is lowered into a sample chamber and air is sampled for a preset time period at a preselected flow rate. Lifting the capillary introduces an aliquot from the film for analysis. The capillary is then dipped into a running electrolyte source vial and electrophoresis is commenced.

Abstract: A method for determining a component of interest in a fluid, the method comprising four steps. The first step is to suspend a droplet or a film of a liquid. The second step involves contacting the fluid with the droplet or film. The third step involves diffusing at least a portion of the component of interest into the droplet or film to form an analyte. The fourth step involves determining the component of interest by analyzing the analyte. The fluid can be either a liquid or a gas. The analyte can be analyzed while in the form of a suspended droplet or film.

Abstract: Apparatus for capillary electrophoresis having an auxiliary electroosmotic pump. Following a conventional capillary electrophoresis system having a single power supply, a separation capillary, and an optical detector, a conductive membrane connects a second capillary to a second power supply. The second capillary and second power supply act together as an auxiliary electroosmotic pump capable of augmenting or inhibiting the bulk electroosmotic flow in the separation capillary. The apparatus can be used to optimize the stacking profile of the sample and, thus, improve the separation efficiencies for charged solutes.

Abstract: Method and apparatus for flow injection analysis (FIA) using an electroosmotic pump. The apparatus includes: an electroosmotic pump having a grounding joint; a sample injection valve for introducing a sample into a carrier stream which valve is in fluid communication with the grounding joint by way of a conduit; a dispersion coil in fluid communication with the sample injection valve; and a detector which is in fluid communication with the dispersion coil. The grounding joint couples the electroosmotic pumping system and the FIA system but electrically isolates them.Generally, the method utilizes one fluid which is electroosmotically pumped to propel a carrier for flow injection analysis at a controllable flow rate. More specifically, the method includes the steps of: adding a sample to a liquid carrier stream to form a sample zone in the carrier stream; flowing a liquid pumping stream by electroosmosis; and connecting the pumping stream with the carrier stream to propel the carrier stream.