Abstract: A piston seal assembly for a pipette includes an O-ring having radially inner and outer surfaces and axially separated first and second surfaces. A seal includes a radially extending rim portion having axially separated first and second surfaces and an axially extending sleeve portion forming an opening. A seat includes an axially extending indexing portion and a radially extending engagement portion forming an opening and having axially separated first and second surfaces. The seal is positioned such that the pipette piston extends through the opening and the radially inner surface of the sleeve portion slidably engages the piston. The seat is positioned such that the piston extends through the opening, the first and second surfaces of the engagement portion engage the second surface of the rim portion and an end of the spring, respectively, and the radially outer surface of the indexing portion engages the inner surface of the pipette body.

Abstract: A photometric detection system including a light source, a photometric detector, and a flow cell assembly. The flow cell assembly includes a tubular liquid core waveguide having inlet and discharge ends for receiving and discharging a flow of the sample fluid. A first coupling device optically couples the light source to the waveguide at a first position along the length of the waveguide. A second coupling device optically couples the detector to the waveguide at a second position along the length of the waveguide. The first and second positions define an optical path length within the waveguide. The second position is variable relative to the first position such that the optical path length is selectively varied.

Abstract: A photometric detection system including a light source, a photometric detector, and a flow cell assembly. The flow cell assembly includes a tubular liquid core waveguide having inlet and discharge ends for receiving and discharging a flow of the sample fluid. A first coupling device optically couples the light source to the waveguide at a first position along the length of the waveguide. A second coupling device optically couples the detector to the waveguide at a second position along the length of the waveguide. The first and second positions define an optical path length within the waveguide. The second position is variable relative to the first position such that the optical path length is selectively varied.

Abstract: The detection of a chemical specie of interest is accomplished by immobilizing sensing molecules on the inner wall of a liquid core optical waveguide, the waveguide comprising a capillary tube and the sensing molecules being selected to interact with the specie of interest carried by the liquid which forms the waveguide core. The interaction produces a change in an optical characteristic of the waveguide which may be detected by illuminating the waveguide with analysis light.

Abstract: A gas or vapor 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 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. Sensitivity is enhanced by controlling the pressure differential across the waveguide wall and/or by shaping the waveguide to enlarge the surface area. When the reaction generates light, the devices which detect that light will be shaped and disposed to maximize the collection thereof.

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: The chemical properties of an aqueous liquid, the liquid comprising a solvent having an index of refraction which is the same as or closely approaches that of water, are determined by Raman spectroscopy wherein a sample of the liquid is delivered into an optical waveguide. The waveguide is in the form of a capillary having a reflective surface defined by a material having a refractive index of less than 1.33. Excitation light is transmitted axially into the liquid at an end of the waveguide. The excitation light is transmitted the length of the waveguide, by reflection from the reflective surface, causing the fluid to emit Raman spectra. The Raman spectra is transmitted along the waveguide, collected and delivered to a spectrometer.

Abstract: Water or some other aqueous fluid is employed as the light transmitting medium of a liquid core fiber-optic waveguide cell by employing, to define the core region, a waveguide vessel having an exterior coating composed of a material having a refractive index of less than 1.33. The light conducting channel defined by the aqueous fluid filled core may be a capillary or other suitably shaped vessel.