Simultaneous chemical separation and surface-enhanced raman spectral detection

• US 20040191921A1
• Filed: 04/05/2004
• Published: 09/30/2004
• Est. Priority Date: 02/21/2003
• Status: Abandoned Application

• Current Assignee: Real-Time Analyzers Incorporated
• Original Assignee: Real-Time Analyzers Incorporated
• Inventors: Farquharson, Stuart, Maksymiuk, Paul
• Application Number:
  US10/818,202
• Publication Number:
  US 20040191921A1
• Time in Patent Office: Days
• US Class Current: 436/172
• CPC Class Codes: B01J 20/02 comprising inorganic material
• CPC Class Codes: B01J 20/06 comprising oxides or hydroxides of metals not provided for in group B01J20/04
• CPC Class Codes: B01J 20/08 comprising aluminium oxide or hydroxide; comprising bauxite
• CPC Class Codes: B01J 20/103 comprising silica
• CPC Class Codes: B01J 20/28004 Sorbent size or size distribution, e.g. particle size
• CPC Class Codes: B01J 20/28047 Gels
• CPC Class Codes: B01J 20/283 based on silica
• CPC Class Codes: B01J 20/284 based on alumina
• CPC Class Codes: B01J 20/286 Phases chemically bonded to a substrate, e.g. to silica or to polymers
• CPC Class Codes: B01J 20/291 Gel sorbents
• CPC Class Codes: B01J 20/3204 Inorganic carriers, supports or substrates
• CPC Class Codes: B01J 20/321 consisting of a polymer obtained by reactions involving only carbon to carbon unsaturated bonds
• CPC Class Codes: B01J 20/3236 containing metal, other than zeolites, e.g. oxides, hydroxides, sulphides or salts
• CPC Class Codes: B01J 2220/54 Sorbents specially adapted for analytical or investigative chromatography
• CPC Class Codes: B01L 2300/0816 Cards, e.g. flat sample carriers usually with flow in two horizontal directions
• CPC Class Codes: B01L 2300/0838 Capillaries
• CPC Class Codes: B01L 2300/087 Multiple sequential chambers
• CPC Class Codes: B01L 2400/0457 passive flow or gravitation
• CPC Class Codes: B01L 3/0275 Interchangeable or disposable dispensing tips
• CPC Class Codes: B01L 3/5023 with a sample being transported to, and subsequently stored in an absorbent for analysis
• CPC Class Codes: G01N 1/40 : Concentrating samples
• CPC Class Codes: G01N 21/63 : optically excited
• CPC Class Codes: G01N 21/658 : enhancement Raman, e.g. surface plasmons
• CPC Class Codes: G01N 30/6082 : transparent to radiation
• 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

A stationary medium is employed both to separate chemicals from a sample solution and also for surface-enhanced Raman spectral analysis of the separated chemical, thereby greatly reducing the complexity of the apparatus and enhancing the efficiency of the chemical analysis method.

Claims

1. A method for substantially simultaneously separating and detecting at least one analyte chemical in a solution, comprising:

transporting a sample solution containing a plurality of chemicals, including at least one analyte chemical, through or along a stationary medium in sufficiently intimate contact with the medium for effecting separation of said at least one analyte chemical, said stationary medium being functional to separate at least one of said plurality of chemicals and also exhibiting surface-enhanced Raman scattering activity;

substantially concurrently irradiating said medium with excitation radiation to generate surface-enhanced Raman scattered radiation;

collecting at least a portion of said surface-enhanced Raman scattered radiation; and

analyzing said collected radiation to determine the presence of said analyte chemical in said sample solution.

2. The method of claim 1 wherein said stationary medium comprises or defines an elongate path for said sample solution.

3. The method of claim 1 wherein said stationary medium incorporates a surface-enhanced Raman active metal selected from the group consisting of silver, gold, copper, and alloys and mixtures thereof.

4. The method of claim 3 wherein said surface-enhanced Raman active metal is of particulate form.

5. The method of claim 4 wherein the particles of said surface-enhanced Raman active metal are of submicron size.

6. The method of claim 4 wherein said surface-enhanced Raman active metal particles comprise metal colloids or metal-coated particles of polystyrene, silica, alumina, zirconia or titania.

7. The method of claim 6 wherein said metal-coated particles are spheres of submicron size.

8. The method of claim 4 wherein said surface-enhanced Raman active metal particles are substantially isolated from one another.

9. The method of claim 3 wherein said surface-enhanced Raman active metal is in the form of particulate groupings, or elements of substantially regular character, to optimize surface-enhanced Raman scattering.

10. The method of claim 9 wherein said particulate groupings are random.

11. The method of claim 9 wherein said particulate groupings are ordered.

12. The method of claim 1 wherein said at least one surface-enhanced Raman active material comprises a fixed surface deposit.

13. The method of claim 1 wherein said stationary medium comprises at least one separation material and at least one surface-enhanced Raman active material.

14. The method of claim 13 wherein said at least one surface-enhanced Raman active material is of particulate form.

15. The method of Claim 13 wherein said at least one separation material is in the form of particles, matrices, gels, sol-gels, or integral elements.

16. The method of claim 13 wherein said at least one separation material comprises an integral element in the form of a porous plug, a membrane, or a fixed surface deposit.

17. The method of claim 14 wherein said at least one separation material is of particulate form, wherein said particulate materials constitute a homogeneous mixture, and wherein said at least one separation material is present in said stationary medium in a volumetric ratio to said at least one surface-enhanced Raman active material in the range of about 1×

10⁶;

1 to 1;

1.

18. The method of claim 1 wherein said stationary medium comprises at least one separation material selected from the group consisting of aero-gels, zero-gels, metal alkoxide-based sol-gels, silica gels, transition metal-stabilized silica, derivatized silica-based matrices, glass beads, long-chain alkanes, derivatized long-chain alkanes, polyomers, derivatized polymers, functionalized membranes, alumina, size-exclusion resins, and ion-exchange resins.

19. The method of claim 1 wherein said stationary medium comprises a liquid chromatography separation material.

20. Apparatus for effecting, substantially simultaneously, separation of at least one analyte chemical from a sample solution containing a plurality of dissolved chemicals, and detection of the at least one analyte chemical, said apparatus comprising:

elongate containment means for containing a stationary medium and being sufficiently transparent to excitation radiation, at least at one location along its length, to permit transmission of excitation radiation effective for generating measurable amounts of surface-enhanced Raman scattered radiation, and being sufficiently transparent to surface-enhanced Raman scattered radiation, at least at said one location, to permit transmission of measurable amounts of such surface-enhanced Raman radiation;

a quantity of stationary medium, functional to separate at least one of the chemicals contained in the sample solution and also exhibiting surface-enhanced Raman scattering activity, contained in said containment means and defining a flow path through said containment means past said at least one location, said medium being of such character as to promote intimate contact with a sample solution transported along said flow path; and

means for defining an entrance for a sample solution to said flow path, said at least-one location being spaced from said entrance along the length of said containment means.

21. The apparatus of claim 20 comprising a filled column of said stationary medium.

22. The apparatus of claim 20 wherein said stationary medium incorporates a surface-enhanced Raman active metal selected from the group consisting of silver, gold, copper, and alloys and mixtures thereof.

23. The apparatus of claim 20 additionally including a microchip card substrate bearing said elongate containment means.

24. The apparatus of claim 23 wherein said elongate containment means comprises a microchannel in said substrate, said substrate having a plurality of ports communicating with said microchannel and providing said entrance-defining means and an exit-defining means.

25. The apparatus of claim 24 wherein said stationary medium comprises a lining deposited on a wall of said elongate containment means and defining said sample flow path.

26. The apparatus of claim 22 wherein said surface-enhanced Raman active metal is of particulate form.

27. The apparatus of claim 26 wherein the particles of said surface-enhanced Raman active metal are of submicron size.

28. The apparatus of claim 26 wherein said surface-enhanced Raman active metal particles comprise metal colloids or metal-coated particles of polystyrene, silica, alumina, zirconia or titania.

29. The apparatus of claim 28 wherein said metal-coated particles are spheres of submicron size.

30. The apparatus of claim 28 wherein said surface-enhanced Raman active metal particles are substantially isolated from one another.

31. The apparatus of claim 28 wherein said surface-enhanced Raman active metal is in the form of particulate groupings or elements of substantially regular character, to optimize surface-enhanced Raman scattering.

32. The apparatus of claim 23 wherein said at least one surface-enhanced Raman active material comprises a fixed surface deposit.

33. The apparatus of claim 23 wherein said stationary medium comprises at least one separation material and at least one surface-enhanced Raman active material.

34. The apparatus of claim 33 wherein said at least one surface-enhanced Raman active material is of particulate form.

35. The apparatus of claim 33 wherein said at least one separation material is in the form of particles, matrices, gels, sol-gels, or integral elements.

36. The apparatus of claim 33 wherein said at least one separation material companies an integral element in the form of a porous plug, a membrane, or a fixed surface deposit.

37. The apparatus of claim 34 wherein said at least one separation material is of particulate form, wherein said particulate materials constitute a homogeneous mixture, and wherein said at least one separation material is present in said stationary medium in a volumetric ratio to said at least one surface-enhanced Raman active material in the range of about 1×

10⁶;

1 to 1;

1.

38. The apparatus of claim 23 wherein said stationary medium comprises at least one separation material selected from the group consisting of aero-gels, zero-gels, metal alkoxide-based sol-gels, silica gels, transition metal-stabilized silica, derivatized silica-based matrices, glass beads, long-chain alkanes, derivatized long-chain alkanes, polyomers, derivatized polymers, functionalized membranes, alumina, size-exclusion resins, and ion-exchange resins.

39. The apparatus of claim 23 wherein said stationary medium comprises a liquid chromatography separation material.