Liquid photometer using surface tension to contain sample
OwnerCharles William Robertsoninventor
Life of this patent
Estimating the term…
Abstract
Method and apparatus of spectrophotometry or the like on extremely small liquid samples in which a drop is held between two opposing surfaces by surface tension and one surface is controllably moved toward and away from the other. To provide and transmit exciting energy through the drop for measurement, the optical fibers go through a surface and are finished flush with its surface. One of the surfaces can be swung clear of the other for easy cleaning between tests.
Claims31
A photometric or spectrophotometric apparatus wherein a sample in the form of a liquid drop is contained by surface tension forces between two planar surfaces, one containing a photometric or spectrophotometric source and the other a photometric or spectrophotometric detector and an optical path is established through the sample between the two surfaces
A fluormetric or spectrofluormetric system wherein the sample is contained by surface tension between two surfaces, wherein the system source and detector are contained in one or both of the surfaces.
An apparatus for performing optical measurements on microliter or sub-microliter liquid samples comprising a frame, a fixed surface or anvil mounted on the frame, a moveable surface or anvil mounted to the frame in substantial parallel opposition to the fixed anvil surface in at least one position, at least two optical fibers penetrating at least one of the surfaces, each of the fibers finished flush with its respective surface, means to move the moveable anvil surface to at least one controlled spacing from the fixed surface and means to perform an optical measurement of the properties of the microliter or sub-microliter liquid sample disposed between the surfaces employing at least one fiber to deliver light to the sample and at least one other fiber to transmit transmitted or excited energy to a detector.
An apparatus wherein the sample is contained in a small vessel with flexible walls such that the sample can be pulled into a measurement column between the fixed and moveable anvil surfaces and its absorbance measured as a difference in absorbance between two optical pathlengths.
In apparatus for the photometric or spectrophotometric measurement of small liquid volume samples the improvement comprising holding the sample by surface tension between two surfaces, adjusting the distance between those two surface to a selected distance and performing the measurement employing a photometric or specrophotometric source and a photometric or specrophotometric detector each in one of the surfaces.
A method of performing a photometric or spectrophotometric measurement on a microdrop liquid sample comprising:
- placing the sample on one of two relatively moveable opposing surfaces, or placing a part of the sample on each sutrface;
- moving the surfaces toward each other a preselecv6ed distance to spread the sample and to wet the surfaces;
- moving the surfaces apart from each other a preselected distance whereby the sample is contained between tuhe surfaces by surface tension;
- and performing the photometric or spectrophotometric measurement.
Dependencies are inferred from the claim text.