Liquid photometer using surface tension to contain sample

• US 6,809,826 B2
• Filed: 02/19/2002
• Issued: 10/26/2004
• Est. Priority Date: 02/20/2001
• Status: Expired due to Term

• Current Assignee: NanoDrop Technologies LLC (Thermo Fisher Scientific Incorporated)
• Original Assignee: Charles William Robertson
• Inventors: Robertson, Charles William
• Primary Examiner(s): Rosenberger, Richard A.
• Application Number:
  US10/078,717
• Publication Number:
  US 20020140931A1
• Time in Patent Office: 980 Days
• Field of Search: 356/246, 356/436, 356/440
• US Class Current: 356/440
• CPC Class Codes: B82Y 15/00 Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
• CPC Class Codes: G01N 2021/035 Supports for sample drops
• CPC Class Codes: G01N 21/01 Arrangements or apparatus for facilitating the optical investigation

Abstract

Method and apparatus of spectroscopy or the like on extremely small samples in which a drop is held between two opposing surfaces by surface tension and one surface is controllably toward and away from the other. To provide and transmit exciting energy through the drop for measurement, optical fibers go through a surface and finish flush with the surface. One of the surfaces can be swung clear of the other for easy cleaning between tests. Means for determining wetted surface are provided.

Claims

1. A photometric or spectrophotometric apparatus wherein a sample in the form of a liquid drop is contained in tension by surface tension forces between two 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, said apparatus comprising:

first and second anvil surfaces at least one being moveable relative the other to any one of three positions;

an adjustable sample loading position so selected that the at least one moveable surface and the other surface are so remotely spaced that a liquid sample can be placed on the first surface;

an adjustable sample compression position so selected that the surfaces are opposed and substantially parallel and proximally spaced so that the liquid wets and spreads upon both surfaces; and

an adjustable sample measuring position so selected that the opposed substantially parallel surfaces are spaced apart to pull the sample into a column wherein it is contained in tension by surface tension thereby providing an optical path for a photometric or spectrophotometric measurement;

the improvement comprising;

providing means for limiting the surface area of the drawn column on at least one surface.

2. The apparatus of claim 1 wherein the surface area is limited by providing the surface area with a sharp edge.

3. The apparatus of claim 1 wherein the anvils are of unequal size.

4. The apparatus of claim 1 wherein the surface area is limited by providing the surface area with a change in surface tension characteristics.

5. The apparatus of claim 4 wherein the surface area is delimited by a low-surface-tension polymeric material forming a boundary.

6. The apparatus of claim 4 wherein the delimitation is bound on the inside.

7. The apparatus of claim 4 wherein the delimitation is bound on the outside.