Methods and apparatus for measuring the light absorbance of a substance in a solution

• US 9,322,772 B2
• Filed: 05/30/2013
• Issued: 04/26/2016
• 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
• Primary Examiner(s): Kim, Kiho
• Application Number:
  US14/404,860
• Publication Number:
  US 20150153272A1
• Time in Patent Office: 1,062 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, the method comprising:

directing a first light beam outputted from a first light-emitting diode (LED) on the substance, the first light beam having a first wavelength;

quantifying the intensity of the first light beam as it exits the substance;

determining, from the quantified intensity of the first light beam, a first absorbance value of the substance;

determining when a change in the first absorbance value reaches a threshold;

directing, in response to the change reaching the threshold, a second light beam outputted from a second LED on the substance, the second light beam having a second wavelength different than the first wavelength;

quantifying the intensity of the second light beam as it exits the substance; and

determining, from the quantified intensity of the second light beam, a second absorbance value of the substance.

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

3. The method of claim 1, wherein determining the first absorbance value includes (i) directing a first portion of the first light beam to a reference detector, yielding a reference value and (ii) directing a second portion of the first light beam on the substance, yielding a measured value, and (iii) computing the first absorbance based on the measured value and the reference value.

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

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

6. The method of claim 1, wherein the substance is selected from the group consisting of a protein, a peptide, and a nucleic acid.

7. An apparatus for measuring the absorbance of a substance, the apparatus comprising:

a first light emitting diode (LED) configured to emit a first light beam having a first wavelength;

a second LED configured to emit a second light beam having a second wavelength;

a sample holder configured to hold the substance; and

a controller programmed to;

(i) direct the first light beam on the substance;

(ii) quantify the intensity of the first light beam as it exits the substance;

(iii) determine, from the quantified intensity of the first light beam, a first absorbance value of the substance;

(iv) determine when a change in the first absorbance value reaches a threshold;

(v) direct, in response to the change reaching the threshold, a second light beam outputted from a second LED on the substance, the second light beam having a second wavelength different than the first wavelength;

(vi) quantify the intensity of the second light beam as it exits the substance; and

(vii) determine, from the quantified intensity of the second light beam, a second absorbance value of the substance.

8. The apparatus of claim 7, wherein the apparatus further includes a beam splitter, a reference detector, and a sample detector.

9. The apparatus of claim 7, wherein one of the first LED and the second LED is a UV LED.

10. The apparatus of claim 7, further including a moveable support supporting the first LED and the second LED.

11. The apparatus of claim 10, wherein the support comprises a rotatable carousel supporting each of the first LED and the second LED.

12. The apparatus of claim 10, wherein the support is configured to move linearly.

13. The apparatus of claim 7, further comprising a moveable reflective surface.

14. The apparatus of claim 7, further comprising an optical fiber associated with the first LED and an optical fiber associated with the second LED.

15. The apparatus of claim 7, further comprising a first filter and a second filter associated with the first LED and the second LED, respectively.