Quantitative transmission spectroscopy using sample carriers with nets

• US 5,786,226 A
• Filed: 03/18/1996
• Issued: 07/28/1998
• Est. Priority Date: 03/16/1995
• Status: Expired due to Fees

• Current Assignee: Boehringer Mannheim GmbH (Roche Holding AG)
• Original Assignee: Boehringer Mannheim GmbH (Roche Holding AG)
• Inventors: Haar, Hans-Peter, Werner, Gerhard, Bocker, Dirk
• Primary Examiner(s): Soderquist, Arlen
• Application Number:
  US08/619,935
• Time in Patent Office: 862 Days
• Field of Search: 436/164, 436/165, 422/56-58, 422/99, 422/102, 422/104, 356/244, 356/246, 446/16, 250/339.07, 250/343
• US Class Current: 436/164
• CPC Class Codes: G01N 2021/0346 Capillary cells; Microcells
• CPC Class Codes: G01N 21/03 Cuvette constructions
• CPC Class Codes: G01N 21/3577 for analysing liquids, e.g. polluted water
• CPC Class Codes: G01N 21/59 Transmissivity G01N21/25 takes precedence

Abstract

Quantitative transmission spectroscopy where a sample liquid is applied onto a sample carrier having a net in such a manner that the liquid spreads across the meshes of the net. The liquid on the net is exposed to radiation essentially perpendicularly to the net, and the transmitted radiation is detected. The net accomplishes a dosing of the liquid in such a manner that identical meshes include identical quantities of liquid. For a given net, it is possible to derive the amount of liquid, which is located in a mesh and accessible to radiation, from a net constant. Knowing the amount of liquid detected by the radiation, it is possible to use the radiation absorption to calculate the concentration of one or several analytes contained in the sample liquid.

Claims

1. A process for performing quantitative transmission spectroscopy, said process comprising the steps of:

a) contacting a sample liquid to a sample carrier, said sample carrier being provided with a net configured such that the sample liquid disperses across a plurality of openings in a mesh of the net, thereby forming a liquid film thereupon, said net having a regular mesh arrangement featuring identical mesh geometry;

b) exposing the sample carrier to a light source, wherein the light source is disposed perpendicular to a plane of the net whereby light from the light source traverses the liquid film substantially perpendicular thereto;

c) detecting light from the light source which is transmitted through the liquid film;

d) calculating a concentration of at least one analyte contained in the sample liquid based upon the detected light and an effective volume V of the sample liquid, wherein the effective volume is calculated according to the formula

space="preserve" listing-type="equation">V=Q·

K.sub.1

wherein Q is a cross section of the light from the light source where the light is exposed to the plane of the net, and wherein K₁ is a variable which is constant for a particular sample carrier, and is indicative of an effective layer thickness of the liquid film formed on the sample carrier.

2. A process for performing quantitative transmission spectroscopy according to claim 1, wherein said step of exposing the sample carrier to a light source comprises exposing the sample carrier to a bundle of light beams.

3. A process according to claim 2, further comprising the step of adjusting the bundle of light beams to pass through a single opening of the plurality of openings in the mesh of the net.

4. A process for performing quantitative transmission spectroscopy according to claim 1, said process comprising, before said step a), the steps of:

1) contacting a calibration liquid to the sample carrier, said calibration liquid being selected to have a predetermined absorption coefficient, wherein the calibration liquid spreads across the openings of the mesh of the net to form a calibration film thereupon;

2) exposing the sample carrier to the light source whereby light from the light source impinges upon of the calibration film ;

3) detecting light from the light source which is transmitted through the calibration film;

4) calculating the effective volume V of the calibration liquid based upon the detected light and the predetermined absorption coefficient of the calibration liquid, and calculating constant K₁ according to the formula

space="preserve" listing-type="equation">K.sub.1 =V/Q

then proceeding with step a).

5. A process according to claim 4, wherein a diameter of a light beam from the light source is less than a diameter of the calibration film.

6. A process according to claim 1, wherein the liquid film is dried before the sample carrier is exposed to the light source.

7. A process according to claim 6, wherein the sample liquid is dried when the sample carrier is in a horizontal position.

8. A process according to claim 1, wherein said contacting step is conducted by immersing the sample carrier in the sample liquid.

9. A process according to claim 1, wherein said contacting step is conducted by pipetting the sample liquid onto the sample carrier.

10. A process according to claim 1, wherein said contacting step is conducted by applying the sample liquid with a stamp.

11. A process according to claim 1, including a first step of providing a serum as the sample liquid.

12. A process according to claim 1, comprising a step of adding a detergent to the sample liquid.

13. A process according to claim 1, comprising the step of providing an infrared light source as the light source.

14. A process according to claim 1, further comprising a step of adjusting a diameter of a light beam from the light source such that the light beam passes through a single opening of the plurality of openings in the mesh of the net.

15. A process according to claim 1, wherein the sample liquid which is contacted to the sample carrier has a volume range of 1 nl to 100 μ

l.

16. A process according to claim 1, wherein the sample liquid which is contacted to the sample carrier has a volume range of 0.2 to 2.0 μ

l.

17. A process according to claim 1, wherein a diameter of a light beam from the light source is less than a diameter of the liquid film.

18. A process according to claim 1, comprising a first step of providing the sample carrier wherein the net is formed of a non-absorbing material.

19. A process according to claim 1, comprising a first step of providing each of the plurality of openings in the net with a diameter of 100 μ

m-2 mm.

20. A process for performing quantitative transmission spectroscopy, said process comprising the steps of:

a) contacting a sample liquid to a sample carrier, said sample carrier being provided with a net configured such that the sample liquid disperses across a plurality of openings in a mesh of the net, thereby forming a liquid film thereupon, said net having a regular mesh arrangement featuring identical mesh geometry;

b) counting a number of the plurality of openings having the liquid film formed thereupon;

c) exposing the sample carrier to a light source, wherein the light source is disposed perpendicular to a plane of the net, whereby light from the light source impinges upon all of the liquid film substantially perpendicular thereto;

d) detecting light from the light source which is transmitted through the liquid film;

e) calculating a concentration of at least one analyte contained in the sample liquid based upon the detected light and the effective volume V of the sample liquid, wherein the effective volume is calculated according to the formula

space="preserve" listing-type="equation">V=N·

K.sub.2

wherein N is the number of openings covered with the liquid film, and wherein K₂ is a variable which is constant for a particular sample carrier, and is indicative of an effective liquid volume retained by one of the openings having the liquid film therein.

21. A process for performing quantitative transmission spectroscopy according to claim 20, wherein said step of exposing the sample carrier to a light source comprises exposing the sample carrier to a bundle of light beams.

22. A process for performing quantitative transmission spectroscopy according to claim 20, said process comprising, before said step a), the steps of:

1) contacting a calibration liquid to the sample carrier, said calibration liquid being selected to have a predetermined absorption coefficient, wherein the calibration liquid disperses across a plurality of openings in a mesh of the net, thereby forming a calibration film thereupon;

2) counting a number of the plurality of openings having the calibration film formed thereupon;

3) exposing the sample carrier to the light source, wherein the light source is disposed perpendicular to a plane of the net, whereby light from the light source impinges upon all of the calibration film, wherein a diameter of the light is at least as great as a diameter of the calibration film on the net;

4) detecting light from the light source which is transmitted through the calibration film;

5) calculating the effective volume V of the calibration liquid based upon the detected light and the predetermined absorption coefficient of the calibration liquid, and calculating constant K₂ according to the formula

space="preserve" listing-type="equation">K.sub.2 =V/N,

wherein N is the number of openings having the calibration film formed thereupon;

then proceeding with step a).

23. A process according to claim 20, wherein the liquid film is dried before the sample carrier is exposed to the light source.

24. A process according to claim 23, wherein the sample liquid is dried when the sample carrier is in a horizontal position.

25. A process according to claim 20, wherein said contacting step is conducted by immersing the sample carrier in the sample liquid.

26. A process according to claim 20, wherein said contacting step is conducted by pipetting the sample liquid onto the sample carrier.

27. A process according to claim 20, wherein said contacting step is conducted by applying the sample liquid with a stamp.

28. A process according to claim 20, including a first step of providing a serum as the sample liquid.

29. A process according to claim 20, comprising a step of adding a detergent to the sample liquid.

30. A process according to claim 20, comprising the step of providing an infrared light source as the light source.

31. A process according to claim 20, further comprising a step of adjusting a diameter of a light beam from the light source such that the light beam passes through a single opening of the plurality of openings in the mesh of the net.

32. A process according to claim 20, wherein the sample liquid which is contacted to the sample carrier has a volume range of 1 nl to 100 μ

l.

33. A process according to claim 20, wherein the sample liquid which is contacted to the sample carrier has a volume range of 0.2 to 2.0 μ

l.

34. A process according to claim 20, wherein a diameter of a light beam from the light source is less than a diameter of the liquid film.

35. A process according to claim 20, comprising a first step of providing the sample carrier wherein the net is formed of a non-absorbing material.

36. A process according to claim 20, comprising a first step of providing each of the plurality of openings in the net with a diameter of 100 μ

m-2 mm.

37. A method for dosing liquids, comprising the steps of:

a) contacting a sample liquid to a sample carrier, said sample carrier being provided with a net configured such that the sample liquid disperses across a plurality of openings in the mesh of the net to form a liquid film thereupon, said net having a regular mesh arrangement featuring identical mesh geometry;

b) counting a number of the plurality of openings having the liquid film formed thereupon;

c) calculating the liquid volume V disposed on the sample carrier using the formula

space="preserve" listing-type="equation">V=N·

K.sub.3

wherein N is the number of openings having the liquid film formed thereupon, and wherein K₃ is a variable which is constant for a particular sample carrier, and is indicative of a volume of sample liquid retained by one opening of said plurality of openings.

38. A method for performing quantitative transmission spectroscopy according to claim 37, wherein said step of exposing the sample carrier to a light source comprises exposing the sample carrier to a bundle of light beams.

39. A method according to claim 37, wherein said contacting step is conducted by immersing the sample carrier in the sample liquid.

40. A method according to claim 37, wherein said contacting step is conducted by pipetting the sample liquid onto the sample carrier.

41. A method according to claim 37, wherein said contacting step is conducted by applying the sample liquid with a stamp.

42. A method according to claim 37, including a first step of providing a serum as the sample liquid.

43. A method according to claim 37, comprising a step of adding a detergent to the sample liquid.

44. A method according to claim 37, comprising the step of providing an infrared light source as the light source.

45. A method according to claim 37, wherein the sample liquid which is contacted to the sample carrier has a volume range of 1 nl to 100 μ

l.

46. A method according to claim 37, wherein the sample liquid which is contacted to the sample carrier has a volume range of 0.2 to 2.0 μ

l.

47. A method according to claim 37, comprising a first step of providing the sample carrier wherein the net is formed of a non-absorbing material.

48. A method according to claim 37, comprising a first step of providing each of the plurality of openings in the net with a diameter of 100 μ

m-2 mm.

49. A method of quantitative transmission spectroscopy, said method comprising the steps of:

a) mixing a predetermined volume of a sample liquid with a predetermined volume of a calibration liquid having a predetermined absorption coefficient, thereby forming a mixed sample having an internal standard;

b) contacting the mixed sample to a sample carrier, said sample carrier being provided with a net configured such that the mixed sample disperses across a plurality of openings in a mesh of the net, thereby forming a liquid film thereupon, said net having a regular mesh arrangement featuring identical mesh geometry;

c) exposing the sample carrier to a light source, wherein the light source is disposed perpendicular to a plane of the net;

d) detecting light from the light source which is transmitted through the liquid film;

e) determining absorption of light by analyses in the sample liquid and by the calibration liquid based upon the detected transmitted light;

f) determining a volume of the mixed sample based upon the internal standard as determined by the absorption of the calibration liquid, then calculating a volume of the sample liquid based upon a mixing ratio of the predetermined volume of the sample liquid and the predetermined volume of the calibration liquid; and

g) calculating a concentration of the analytes in the sample liquid based upon the calculated volume and the detected light.

50. A method according to claim 49, wherein the liquid film is dried before the sample carrier is exposed to the light source.

51. A method according to claim 50, wherein the sample liquid is dried when the sample carrier is in a horizontal position.

52. A method according to claim 49, wherein the sample liquid which is contacted to the sample carrier has a volume range of 1 nl to 100 μ

l.

53. A method according to claim 49, wherein the sample liquid which is contacted to the sample carrier has a volume range of 0.2 to 2.0 μ

l.

54. A method according to claim 49, wherein said step of exposing the sample carrier to a light source comprises exposing the sample carrier to a bundle of light beams.