METHODS AND APPARATUS FOR MEASURING THE LIGHT ABSORBANCE OF A SUBSTANCE IN A SOLUTION

• US 20150153272A1
• Filed: 05/30/2013
• Published: 06/04/2015
• Est. Priority Date: 05/31/2012
• Status: Active Grant

• Current Assignee: Cytiva Sweden AB (Danaher Corporation)
• Original Assignee: GE Healthcare Bio-Sciences AB (General Electric Company)
• Inventors: Ehring, Hanno, Jarhede, Fredrik Lars, Ostlund, Erik
• Granted Patent: US 9,322,772 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01N 2021/3181 using LEDs
• CPC Class Codes: G01N 2030/8827 involving nucleic acids
• CPC Class Codes: G01N 21/3151 using two sources of radiation of different wavelengths G01N21/33 - G01N21/39 take precedence
• CPC Class Codes: G01N 21/33 using ultraviolet light G01N21/39 takes precedence
• CPC Class Codes: G01N 2201/062 LED's
• 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

Disclosed is an apparatus for measuring the absorbance of a substance in a solution, comprising: i) a sample cell (30) of known path length (b) for containing said solution (S), said cell being transparent to light of a predefined wavelength spectrum; ii) plural LED'"'"'s each being independently operable by means of a controller (25) each for emitting light, within said predefined wavelength spectrum, along a light path; iii) a band pass filter (22) in the light path; iv) a beam splitter (24) for dividing light from said source propagating along the path into a first portion and a second portion, said first portion being directable by the beam splitter toward a reference detector (42) and said second portion being directable into the cell (30); v) a reference detector (42) for detecting the intensity of said first portion of light directed by said beam splitter; and vi) a sample detector (40) for detecting the intensity of the second portion propagating from the cell; the apparatus allowing a sample in the cell to be inexpensively subjected to more than one wavelength of light for quicker or more accurate analysis.

Claims

1. A method for measuring the absorbance of a substance in a solution, the substance exhibiting light absorption, the method comprising the steps, in any suitable order, of:

i) transmitting light having a first wavelength output from a first LED light source;

ii) directing the light output from the LED through the substance in solution; and

iii) quantifying the intensity of the light propagating from the solution to provide an indication of the concentration of the substance in the solution;

the method being characterised in that the steps i) to iii) are repeated using a second LED light source having an output of a second wavelength different from the first wavelength.

2. The method of claim 1, wherein said light propagating from the first LED light source is directed through a first band pass filter corresponding to the first wavelength and wherein said light from the second LED light source is directed through a second band pass filter corresponding to the second wavelength.

3. The method of claim 1, wherein light from the first and second LED light sources is caused to propagate through a beam-splitter, thereby directing a first portion of the light from the beam-splitter toward a reference detector and thereby directing a second portion of the light into said solution;

and wherein step iii) further includes, quantifying the intensity of said first portion of the light at said reference detector thereby obtaining a reference value;

quantifying the intensity of said second portion of the light once transmitted through the solution thereby obtaining a sample value; and

calculating the solution'"'"'s absorbance (A) from said sample value and said reference value.

4. The method of claim 1 wherein the first and/or second LEDs are UV LED'"'"'s.

5. The method of claim 1, wherein the solution is selected from the group consisting of cell extract, cell lysate and cell culture or mixtures thereof.

6. The method of claim 1, wherein said substance is a protein or a peptide, or a nucleic acid.

7. The method of claim 1, wherein the steps i) to iii) at the first wavelength and then at the second wavelength, are all further repeated cyclically.

8. The method of claim 7, wherein the cyclical repeating of steps is carried out according to a predefined timescale.

9. The method of claim 1 wherein, the repeating of steps i) to iii) at the second wavelength is carried out in response to a change in the solution'"'"'s absorbance value flowing steps i) to iii) carried out at the first wavelength.

10. Apparatus for measuring the absorbance of a substance in a solution, comprising:

i) at least one sample cell of known path length for containing said solution, said cell being at least partially transparent to light of a predefined wavelength spectrum;

ii) an LED light source arrangement for emitting light, within said predefined wavelength spectrum, along a light path; and

optionally

iii) a band pass filter in the light path;

the apparatus being characterised in that said LED light source arrangement includes plural LED'"'"'s each having a different wavelength light output within the spectrum and said arrangement being operable to provide light along the light path from one or more of the LEDs, and optionally in that plural band pass filters are provided corresponding to said wavelengths.

11. Apparatus as claimed in claim 10, including a controller operable to select the LED used to provide said light along the light path.

12. Apparatus as claimed in claim 10, wherein the apparatus further includes:

iv) a beam splitter for dividing light from said source propagating along the path into a first portion and a second portion, said first portion being directable by the beam splitter toward a reference detector and said second portion being directable into the cell;

v) a reference detector for detecting the intensity of said first portion of light directed by said beam splitter; and

vi) a sample detector for detecting the intensity of the second portion propagating from the cell.

13. Apparatus as claimed in claim 10, wherein at least one of the LEDs is a UV LED.

14. Apparatus as claimed in claim claim 10, wherein the LED arrangement further includes a movable LED support, supporting said plural LEDs, said support allowing movement of each of the LEDs into and out of the light path.

15. Apparatus as claimed in claim 14, wherein the support comprises a rotatable carousel supporting each LED, for presenting each LED in turn at the light path by means of rotation of the carousel.

16. Apparatus as claimed in claim 14, wherein the support comprises an array for presenting each LED in turn at the light path by means of linear movement, to provide UV light along the light path.

17. Apparatus as claimed in claim 10, wherein the light source arrangement includes a moveable reflective surface providing optical alignment between a selected one of each of the plural sources of light and said light path.

18. Apparatus as claimed in claim 10, wherein the LED arrangement further includes an optical fibre associated with each LED, or a single optical fibre, in either case the optical fibre(s) being arranged to provide an optical path allowing light from each LED to propagate to the light path.

19. Apparatus as claimed in claim 17 wherein each filter is mounted to a moveable, for example rotary, support to bring each filter into the light path.

20. Apparatus as claimed in claim 11 wherein a controller is operable to perform the in any suitable order, of the steps of:

i) transmitting light having a first wavelength output from a first LED light source;

ii) directing the light output from the LED through the substance in solution; and

iii) quantifying the intensity of the light propagating from the solution to provide an indication of the concentration of the substance in the solution;

the method being characterised in that the steps i) to iii) are repeated using a second LED light source having an output of a second wavelength different from the first wavelength.

21. Apparatus as claimed in claim 10 further including two or more sample cells each having a different light path and each light path being suppliable with light from an associated LED, each associated LED providing a different wavelength of light to its respective sample cell.

22. (canceled)