Opaque additive to block stray light in amorphous fluoropolymer light-guiding flowcells

• US 7,362,429 B2
• Filed: 08/04/2004
• Issued: 04/22/2008
• Est. Priority Date: 02/25/2002
• Status: Expired due to Fees

• Current Assignee: Waters Technologies Corporation (Waters Corporation)
• Original Assignee: Waters Investments Limited (Waters Corporation)
• Inventors: Gilby, Anthony C.
• Primary Examiner(s): Evans; F L.
• Assistant Examiner(s): Giglio; Bryan J
• Application Number:
  US10/911,126
• Publication Number:
  US 20050078308A1
• Time in Patent Office: 1,357 Days
• Field of Search: 356/246, 356/436, 356/446, 356441-442, 385/145, 385/144
• US Class Current: 356/246
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 2021/052 Tubular type; cavity type; multireflective
• CPC Class Codes: G01N 21/0303 Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment G01N21/031 - G01N21/15 take precedence
• CPC Class Codes: G01N 21/05 Flow-through cuvettes G01N21/09 takes precedence; handling fluid samples G01N1/10
• CPC Class Codes: G01N 21/552 Attenuated total reflection
• CPC Class Codes: G01N 2201/064 Stray light conditioning
• CPC Class Codes: G01N 30/74 Optical detectors measurement of intensity, velocity, spectral content, polarisation, or phase of infrared, visible or ultraviolet light G01J

Abstract

The present invention is directed to the use of a light absorbing wall material to eliminate stray light paths in light-guiding structures, such as those used for HPLC absorbance detection. More specifically, the present invention relates to the use of carbon-doped Teflon® AF, or “black Teflon® AF,” for all or part of the walls of a light-guiding flowcell adapted for use in HPLC absorbance detection.

Claims

1. A set of light-guiding flowcells for a fluid comprising:

a set of channels formed in a substrate of material having an index of refraction lower than an index of said fluid and an absorption coefficient sufficient to substantially attenuate light propagating through said material;

a set of channel covers formed in a section of material having an index of refraction identical to said substrate material and an absorption coefficient sufficient to substantially attenuate light propagating through said material, said set of channel covers fixed to said set of channels forming a set of covered channels;

at least one covered channel having a fluid inlet and outlet port configured off an axis of said covered channel;

at least one covered channel having a source of light at a light entrance end and having a light exit end;

whereby said at least one covered channel and fluid effect guiding of said light by attenuated total reflection and said at least one covered channel has minimal absorptive effect on said light guided by internal reflection.

2. The set of light-guiding flowcells of claim 1 further comprising an optical fiber bonded to at least one covered channel providing said light source of light.

3. The set of light-guiding flowcells of claim 1 whereby the material forming said set of covered channels prevents light crosstalk between flowcells.

4. The set of light-guiding flowcells of claim 1 wherein at least one covered channel is configured as a separation column.

5. The set of light-guiding flowcells of claim 1 wherein at least one covered channel is configured as a fluidic connection.

6. The set of light-guiding flowcells of claim 1 wherein said substrate and said set of covered channels are formed of an amorphous fluoropolymer doped with a black dopant at a concentration of between 0.01-0.1% of the fluoropolymer.

7. The set of light-guiding flow cells of claim 6 wherein the back dopant is carbon black.