Spectrophotometric measurement in a chemical testing apparatus
AssigneeHycel, Inc.
InventorLap Y. Lee
Life of this patent
Estimating the term…
Abstract
In a spectrophotometric measuring apparatus sample liquid is pumped into a substantially cylindrical cuvette having an internal dimension such that a meniscus of a leading edge of a liquid sample pumped therethrough is maintained. Radiant energy directed through the sample liquid is directed across the path of fluid flow rather than along the length thereof. Consequently, spectrophotometric measurement is performed using a significantly reduced optical pathlength.
Claims16
In an analysis station in a chemical testing apparatus, spectrophotometric measuring apparatus comprising a substantially horizontal elongated optically transmissive cuvette defining a liquid sample flow path along a longitudinal axis, conduit means connected for supplying liquid sample from a reaction container to said cuvette, said conduit means being coupled in a taper to said cuvette to provide a non-turbulent fluid path transition, said cuvette having a pair of parallel opposed flat surfaces along said longitudinal axis separated by an internal dimension no greater than that which will maintain a meniscus at a leading edge of liquid sample when said liquid sample statically occupies said cuvette, a radiant energy source positioned for directing energy through said cuvette along a path substantially perpendicular to said flat surfaces, and first radiant energy detection means positioned for receiving energy directed through said cuvette.
A method of analyzing a sample liquid in a chemical testing apparatus comprising the steps of providing a substantially horizontal elongated optically transmissive cuvette defining a liquid flowpath along a longitudinal axis and having a pair of parallel opposed flat surfaces along said longitudinal axis separated by an internal dimension no greater than that which will maintain a meniscus of a leading edge of liquid sample statically occupying said cuvette, moving a liquid having a leading edge defining a meniscus into said cuvette, maintaining said liquid in said cuvette for a predetermined period of time, moving said liquid from said cuvette and moving a sample liquid having a leading edge defining a meniscus into said cuvette, maintaining said sample liquid in said cuvette for a predetermined period of time, directing radiant energy through said sample liquid along a path substantially perpendicular to said flat surfaces of said cuvette while said sample liquid statically occupies said cuvette, and measuring the radiant energy transmitted from said cuvette.
A method of analyzing a sample liquid in a chemical testing apparatus comprising the steps of providing a substantially horizontal elongated optically transmissive cuvette defining a flow path along a longitudinal axis and having a pair of parallel opposed flat surfaces along said longitudinal axis separated by an internal dimension no greater than that which will maintain a meniscus of a leading edge of liquid statically occupying said cuvette, pumping a first portion of liquid into said cuvette, maintaining said liquid in said cuvette for a predetermined period of time, creating an air interface between said first portion of liquid and a second portion of liquid whereby a meniscus is defined at a leading edge of said second liquid portion, pumping said second portion of liquid into said cuvette, maintaining said second portion of liquid in said cuvette for a predetermined period of time, creating an air interface between said second portion of the liquid and a liquid sample whereby a meniscus is defined at a leading edge of the liquid sample, pumping said second portion of liquid out of said cuvette and said liquid sample into said cuvette, maintaining said liquid sample in said cuvette for a predetermined period of time, directing radiant energy through said sample liquid along a path substantially perpendicular to said flat surfaces while said liquid sample statically occupies and cuvette, and measuring the radiant energy transmitted from said cuvette.
Dependencies are inferred from the claim text.