Apparatus for optical inspection of small volumes of liquid sample and cuvettes therefor

Patent metadata

Field	Value
Publication number	US-10935490-B2
Application number	US-201515513448-A
Country	US
Kind code	B2
Filing date	Sep 29, 2015
Priority date	Sep 29, 2014
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

Abstract

A nephelometer that measures turbidity of low volume suspensions using measurements of light transmitted through and/or scattered by the sample. The sample suspension is placed in a tiered cuvette adapted to facilitate measuring the turbidity of low volume samples. The lower portion of the cuvette has smaller dimensions, in horizontal cross section, than the top portion. Both lower and upper portions have angled surfaces. The lower, smaller portion of the cuvette is interrogated by the nephelometer.

First claim

The invention claimed is:

1. An apparatus for optical interrogation of a sample comprising:
an optical source for an optical signal;
a base having a cuvette receptacle therein, wherein the cuvette receptacle comprises a channel that is adapted to receive a linear array of cuvettes, each cuvette in the linear array comprising a narrower, lower portion comprising a plurality of planar side walls, each side wall at an angle from an adjacent sidewall and a wider, upper portion comprising a plurality of side walls, each side wall at an angle from an adjacent sidewall, the wider, upper portion having a perimeter larger than a perimeter of the narrower, lower portion, the cuvette further comprising a transition region from the wider, upper portion to the narrower, lower portion, wherein the channel is adapted to support the transition region of the cuvette and conform thereto as the narrower, lower portion is suspended in the channel the base adapted to position the cuvette such that the optical source positioned in a first aperture in the base that is configured to define a single optical path for transmitting an optical signal from the optical source directly through the planar side wall of the narrower, lower portion of the cuvette;
a scattered light detector positioned in a second aperture in the base to receive the optical signal from the optical source scattered by contents in the narrower, lower portion of the cuvette, the scattered light detector having a surface positioned approximately parallel to an optical path from the optical source; and
wherein the optical source and scattered light detector are at least partially disposed in apertures in the apparatus, and wherein the base has a single optical source.

2. The apparatus of claim 1 further comprising:
a channel configured to advance a linear series of cuvettes, each cuvette being advanced in series to a measurement position, wherein the lower portion of the cuvette is adjacent to the optical source and scattered light detector for measurement.

3. The apparatus of claim 2 , wherein the apparatus is a nephelometer.

4. The apparatus of claim 1 further comprising a transmitted light detector positioned in a third aperture in the base and a light attenuation filter positioned between the cuvette and the transmitted light detector.

5. The apparatus of claim 4 , wherein the scattered light detector and the transmitted light detector are positioned at a 90 degree angle from each other.

6. The apparatus of claim 4 , wherein the scattered light and transmitted light detectors operate across a visible light spectrum from ultra-violet (UV) to infra-red (IR).

7. The apparatus of claim 6 , wherein a wavelength of detected light is in a range of about 620 to about 750 nm.

8. The apparatus of claim 1 , wherein the optical source is selected from the group consisting of a laser light source and an LED.

9. The apparatus of claim 1 , wherein the first aperture comprises of a focusing lens or a series of apertures positioned intermediate between the optical source and the narrower, lower portion of the cuvette.

10. The apparatus of claim 9 , wherein the focusing lens, aperture or series of apertures collimates light transmitted therethrough.

11. The apparatus of claim 1 , wherein the cuvette is optically transparent.

12. An apparatus for optical interrogation of a sample comprising:
a base;
a channel in the base;
a single optical source for an optical signal positioned in a first aperture in the base such that the base defines a single optical path from the single optical source; and
a first detector positioned in a second aperture in the base to receive the optical signal scattered by a sample disposed in a cuvette in a linear array of cuvettes received by the apparatus, wherein the channel is adapted to receive the linear array of cuvettes, wherein both the channel and each cuvette in the linear array of cuvettes has a narrower, lower portion and a wider, upper portion, the wider, upper portion having a perimeter larger than the perimeter of the narrower, lower portion, and wherein the narrower, lower portion of the cuvettes and the wider, upper portion of the cuvettes each comprises a plurality of planar side walls, each side wall at an angle from an adjacent sidewall, the cuvette further comprising a tapered portion from the wider, upper portion to the lower, narrower portion, wherein the channel is adapted to receive the tapered portion and conform thereto, the apparatus further adapted to position a cuvette in the array of cuvettes so that the lower, narrower portion of the cuvette is suspended in the single optical path from the single optical source such that the first detector detects the optical signal transmitted from the first aperture and scattered by the sample only in the narrower, lower portion of the cuvette; and
wherein the single optical source and first detector are at least partially disposed in apertures in the base, and wherein the linear array of cuvettes is advances through the channel.

13. The apparatus of claim 12 , wherein the apparatus is a spectrometer.

14. The apparatus of claim 12 , wherein the apparatus is a nephelometer further comprising a second detector positioned in a third aperture in the base to receive the optical signal from the optical source transmitted from the first aperture through sample in the narrower, lower portion of the cuvette, the second detector having a surface positioned approximately parallel to an optical path from the optical source to the first detector.

15. The apparatus of claim 14 , wherein the detectors operate across a visible light spectrum from ultra-violet (UV) to infra-red (IR).

16. The apparatus of claim 15 , wherein a wavelength of detected light is in a range of about 620 to about 750 nm.

17. The apparatus of claim 14 further comprising a light attenuation filter positioned between the cuvette and the first detector.

18. The apparatus of claim 14 , wherein the first aperture comprises one of a focusing lens, an aperture or a series of apertures positioned intermediate between the single optical source and the narrower, lower portion of the cuvette.

19. The apparatus of claim 18 , wherein light transmitted to the cuvette is collimated.

20. The apparatus of claim 14 , wherein the optical source is selected from the group consisting of a laser light source and an LED.

21. The apparatus of claim 14 , wherein the first and second detectors are positioned at a 90 degree angle from each other.

22. The apparatus of claim 14 , wherein the cuvette is optically transparent.

23. A method for measuring a turbidity of a sample comprising:
separating at least one linear array of cuvettes from a stack of linear arrays of cuvettes;
providing the separated linear array of cuvettes to a nephelometric apparatus each cuvette in the linear array of cuvettes comprising a narrower, lower portion and a wider, upper portion the wider, upper portion having a perimeter larger than the perimeter of the narrower, lower portion such that the narrower, lower portion of a first cuvette will fit within the wider, upper portion of a second cuvette thereby permitting the first cuvette to be stacked onto the second cuvette, wherein the narrower lower portion and the wider upper portion each comprises a plurality of planar side walls, each side wall at an angle from an adjacent sidewall, the cuvette further comprising a tapered portion from the wider, upper portion to the narrower, l

Assignees

• Bd Kiestra Bv

Inventors

• Langhoff Brian Reuben
• Fox William Alan
• Smith Kerry Lynn

Classifications

• G01N21/0303 Primary

  Optical path conditioning in cuvettes, e.g. windows; adapted optical elements or systems; path modifying or adjustment (G01N21/031 - G01N21/15 take precedence) · CPC title

• G01N2021/0385

  Diffusing membrane; Semipermeable membrane · CPC title

• G01N21/253

  for batch operation, i.e. multisample apparatus (analytical automats G01N35/00) · CPC title

• G01N2021/513

  Cuvettes for scattering measurements · CPC title

• G01N21/51 Primary

  inside a container, e.g. in an ampoule (G01N21/53 takes precedence) · CPC title