Method for optically measuring chemical analytes

• US 5,624,847 A
• Filed: 08/06/1993
• Issued: 04/29/1997
• Est. Priority Date: 05/03/1991
• Status: Expired due to Term

• Current Assignee: Joseph R. Lakowicz
• Original Assignee: Joseph R. Lakowicz
• Inventors: Szmacinski, Henryk, Lakowicz, Joseph R.
• Primary Examiner(s): SNAY, JEFFREY R
• Application Number:
  US08/102,806
• Time in Patent Office: 1,362 Days
• Field of Search: 436/68, 436/138, 436/133, 436/163, 436/166, 436/172, 436/74, 128/633, 128/634
• US Class Current: 436/68
• CPC Class Codes: G01N 21/6408 with measurement of decay time, time resolved fluorescence
• CPC Class Codes: G01N 31/223 for investigating presence of specific gases or aerosols G01N31/221, G01N31/222 take precedence; actuation of fire alarm by presence of smoke or gases G08B17/10
• CPC Class Codes: G01N 33/4925 measuring blood gas content, e.g. O2, CO2 , HCO3
• CPC Class Codes: G01N 33/52 Use of compounds or compositions for colorimetric, spectrophotometric or fluorometric investigation, e.g. use of reagent paper and including single- and multilayer analytical elements immunological elements G01N33/54386; involving labelled immunochemicals G01N33/58; for haemoglobin or occult blood G01N33/72
• CPC Class Codes: G01N 33/582 with fluorescent label
• CPC Class Codes: G01N 33/84 involving inorganic compounds or pH

Abstract

A system and method in which a photoluminescent ligand is added to a sample to be analyzed in the form of a photoluminescent probe having intrinsic analyte-induced lifetime changes. The method preferably employs phase-modulation fluorometry to measure the lifetime changes. Specific probes are disclosed for measuring various analytes, particularly ionic solutes, including H⁺, Ca²⁺ and K⁺.

Claims

1. A method of optically measuring analytes, said method comprising the steps of:

adding a photoluminescent ligand probe to a sample to be analyzed, said sample containing an analyte which is an ionic solute, wherein said probe is non-covalently bound to said ionic solute to form an analyte-bound probe species, and wherein bound and unbound species of said probe exist in said sample, said probe having intrinsic analyte-induced lifetime changes;

exciting the sample with radiation;

detecting the resulting emission beam from said bound and unbound species; and

performing a calculation consisting essentially of calculating the apparent luminescence lifetime of the emission to determine the analyte concentration of the sample.

2. A method as in claim 1, wherein said probe is a fluorescent probe.

3. A method as in claim 1, wherein said method is used for the continuous in-vivo monitoring of blood gases.

4. A method as in claim 1, wherein the lifetime is calculated using phase-modulation fluorometry.

5. A method as in claim 1, further comprising the step of changing the apparent concentration sensitivity range of the probe by changing the wavelength of the modulated excitation and/or the wavelength of the emission.

6. A method as in claim 1, wherein the lifetime is calculated using time-resolved fluorometry.

7. A method as in claim 1, wherein the sample is excited using a green helium-neon laser.

8. The method of claim 1, wherein the analyte is the hydronium ion, potassium or calcium.

9. A method as in claim 1, wherein the sample is human blood or a fraction thereof.

10. A method as in claim 9, wherein said probe is selected from the group consisting of seminaphthorhodafluors, seminaphthofluoresceins and resorufins.

11. A method as in claim 1, wherein the sample is excited using a laser diode.

12. A method as in claim 11, wherein the laser diode is intrinsically modulated.

13. A method as in claim 1, wherein the analyte is hydronium ions.

14. A method as in claim 13, wherein said probe is selected from the group consisting of seminaphthorhodafluors, seminaphthofluoresceins and resorufins.

15. A method as in claim 13, wherein said probe is selected from the group consisting of the following formulae:

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16. A method as in claim 13, further comprising the step of calculating carbon dioxide concentration from the hydronium ion concentration.

17. A method as in claim 16, wherein the carbon dioxide concentration is calculated through the bicarbonate couple to pH.

18. A method of optically measuring analytes, said method comprising the steps of:

adding a photoluminescent ligand probe to a sample to be analyzed, said sample containing an analyte which is an ionic solute, wherein said probe is non-covalently bound to said ionic solute to form an analyte-bound probe species, and wherein bound and unbound species of said probe exist in said sample, said probe having intrinsic analyte-induced lifetime changes;

exciting the sample with radiation;

detecting the resulting emission beam from said bound and unbound species; and

performing a calculation utilizing the apparent luminescence lifetime of the emission to determine the analyte concentration of the sample without utilizing fluorescence intensity in said calculation to determine the analyte concentration.