Substance of an optical fluorescence measuring arrangement for measuring the pH of a sample and optical sensor with such an indicator substance

• US 5,308,581 A
• Filed: 07/31/1992
• Issued: 05/03/1994
• Est. Priority Date: 12/12/1990
• Status: Expired due to Term

• Current Assignee: Avl Medical Instruments AG (Roche Holding AG)
• Original Assignee: Avl Medical Instruments AG (Roche Holding AG)
• Inventors: Karpf, Hellfried, Lippitsch, Max, Leiner, Marco J.
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): Torres, Ramon
• Application Number:
  US07/916,154
• Time in Patent Office: 641 Days
• Field of Search: 422/82.06, 422/82.05, 422/82.08, 436/169, 436/501, 350/96.29, 350/96.34
• US Class Current: 422/82.08
• CPC Class Codes: G01N 21/6408 with measurement of decay time, time resolved fluorescence
• CPC Class Codes: G01N 21/6428 Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" in vivo A61B5/00; immunoassay G01N33/53
• CPC Class Codes: G01N 21/6445 Measuring fluorescence polarisation
• CPC Class Codes: G01N 31/221 for investigating pH value

Abstract

An indicator for use in a luminescence-optical configuration for continuous and reversible measurement of the pH of a sample within a relevant measuring range (M), whose luminescence decay time τ is dependent on the pH of the sample, is characterized by the following properties. The pK_a value of the acidic or basic indicator is in the relevant measuring range when the indicator is in its electronic ground state (S₀). The protonation rate k_p of the base, or deprotonation rate k_dp of the acid in the excited state (S₁, X) of the indicator is lower than the decay rate k_A of the excited state, and the luminescence decay times τ_S and τ_B of the acidic forms (AH*, BH^+*) and the basic forms (A^-*, B*) of the indicator are different from each other. If the pK_a τ value of the indicator in its electronically excited state (S₁, X) is within the relevant measuring range, the protonation rate k_p of the base, or deprotonation rate k_dp of the acid in the excited state (S₁, X) of the indicator is higher than the decay rate k_A of the excited state.

Claims

1. A luminescence-optical indicating substance for continuous and reversible measurement of the pH value of a sample within a measuring range M of interest, said sample being at least in indirect contact with said indicating substance provided as a base B*, having a luminescence decay time τ

depending on the pH value of said sample, comprising

a) a pK_a value, in an electric ground state as S₀, which lies in said measuring range M of interest;

b) a protonation rate k_p of said base B* and a deprotonation rate k_dp of conjugate acid BH^+* in an excited state S₁ lower than a decay rate k_A of said excited state; and

c) luminescence decay times τ

_S and τ

_B of said conjugate acid BH^+* and said base B* which differ from each other.

2. An indicating substance according to claim 1, wherein at least two of said excited states of said indicator base B* are in reverse order relative to each other as compared to corresponding excited states of said conjugate acid BH^+*, and wherein a radiationless conversion rate between said at least two excited states of said indicator base B* exceeds said decay rate k_A of said excited states of said indicator base B*.

3. An indicating substance according to claim 1, wherein radiation decay rates k_R of said excited indicator base B* and of said excited conjugate acid BH^+* differ from each other.

4. An indicating substance according to claim 1, wherein a radiationless deexcitation rate k_C of said excited indicator base B* is different from that of said excited conjugate acid BH^+*.

5. A luminescence-optical sensor for continuous and reversible measurement of the pH value of a sample using a chemically or physically immobilized indicator according to claim 1.

6. A luminescence-optical indicating substance for continuous and reversible measurement of the pH value of a sample within a measuring range M of interest, said sample being at least in indirect contact with said indicating substance provided as an acid AH*, having a luminescence decay time τ

depending on the pH value of said sample, comprising

a) a pK_a value, in an electronic ground state as S₀, which lies in said measuring range M of interest;

b) a deprotonation rate k_dp of said acid AH* and a protonation rate k_p of conjugate base A^-* in an excited state S₁ lower than a decay rate of k_A of said excited state; and

c) luminescence decay times τ

_S and τ

_B of said acid AH* and said conjugate base A^-* which differ from each other.

7. An indicating substance according to claim 6, wherein at least two of said excited states of said indicator acid AH* are in reverse order relative to each other as compared to corresponding excited states of said conjugate base A^-*, and wherein a radiationless conversion rate between said at least two excited states of said indicator acid AH* exceeds said decay rate k_A of said excited states of said indicator acid AH*.

8. An indicating substance according to claim 6, wherein radiation decay rates k_R of said excited indicator acid AH* and of said excited conjugate base A^-* differ from each other.

9. An indicating substance according to claim 6, wherein radiationless deexcitation rate k_c of said excited indicator acid AH* is different from that of said excited conjugate base A^-*.

10. A luminescence-optical sensor for continuous and reversible measurement of the pH value of a sample using a chemically or physically immobolized indicator according to claim 6.

11. A luminescence-optical indicating substance for continuous and reversible measurement of the pH value of a sample within a measuring range M of interest, said sample being at least in indirect contact with said indicating substance provided as a base B*, having a luminescence decay time τ

depending on the pH value of said sample, comprising

a) a pK_a * value, in an electronic ground state as S₁, which lies in said measuring range M of interest;

b) a protonation rate k_p of said base B* in said excited state S₁ higher than a decay rate k_A of said excited state; and

c) luminescence decay times τ

_S and τ

_B of conjugate acid BH^+* and said base B* which differ from each other.

12. An indicating substance according to claim 11, wherein at least two of said excited states of said indicator base B* are in reverse order relative to each other as compared to corresponding excited states of said conjugate acid BH^+*, and wherein a radiationless conversion rate between said at least two excited states of said indicator base B* exceeds said decay rate k_A of said excited states of said indicator base B*.

13. An indicating substance according to claim 11, wherein radiation decay rates k_R of said excited indicator base B* and of said excited conjugate acid BH^+* differ from each other.

14. An indicating substance according to claim 11, wherein a radiationless deexcitation rate k_C of said excited indicator base B* is different from that of said excited conjugate acid BH^+*.

15. A luminescence-optical sensor for continuous and reversible measurement of the pH value of a sample using a chemically or physically immobilized indicator according to claim 11.

16. A luminescence-optical indicating substance for continuous and reversible measurement of the pH value of a sample within a measuring range M of interest, said sample being at least in indirect contact with said indicating substance provided as an acid AH*, having a luminescence decay time τ

depending on the pH value of said sample, comprising

a) a pK_a * value, in which an electronic ground state as S₁, which lies in said measuring range M of interest;

b) a deprotonation rate k_dp of said acid AH* in said excited state S₁ higher than a decay rate k_A of said excited state; and

c) luminescence decay times τ

_S and τ

_B of said acid AH* and conjugate base A^-* which differ from each other.

17. An indicating substance according to claim 16, wherein at least two of said excited states of said indicator acid AH* are in reverse order relative to each other as compared to corresponding excited states of said conjugate base A^-*, and wherein a radiationless conversion rate between said at least two excited states of said indicator acid AH* exceeds said decay rate k_A of said excited states of said indicator acid AH*.

18. An indicating substance according to claim 16, wherein radiation decay rates k_R of said excited indicator acid AH* and of said excited conjugate base A^-* differ from each other.

19. An indicating substance according to claim 16, wherein a radiationless deexcitation rate k_C of said excited indicator acid AH* is different from that of said excited conjugate base A^-*.

20. A luminescence-optical sensor for continuous and reversible measurement of the pH value of a sample using a chemically or physically immobilized indicator according to claim 16.