# US 9,040,307 B2 · Fluorescent pH detector system and related methods

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- Number: US 9,040,307 B2
- Document ID: US9040307B2
- Status: Granted
- Kind: B2
- Application number: 13/482,687
- Filed: 2012-05-29
- Published: 2012-12-20
- Granted: 2015-05-26
- Earliest claimed: 2011-05-27
- Assignees: Blood Cell Storage, Inc.
- Applicants: Michael W. Reed; Steven J. Geelhood; Robert O. Dempcy
- Inventors: Michael W. Reed; Steven J. Geelhood; Robert O. Dempcy
- Web page: https://patentgrep.com/patent/US9040307B2

## CPC

- G01N 21/81: Indicating humidity
- G01N 2021/6484: {Optical fibres}
- G01N 2021/7786: {Fluorescence}
- G01N 2201/0846: Fibre interface with sample, e.g. for spatial resolution
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)

## Abstract

Fluorescent pH detector and methods for measuring pH using the fluorescent pH detector.

## Claims

### Claim 1

A method for measuring the pH of a sample, comprising:
(a) irradiating a fluorescent species immobilized on a substrate with excitation light emanating from a probe,
wherein the fluorescent species immobilized on the substrate is in liquid communication with a sample,
wherein the excitation light has a wavelength sufficient to effect fluorescent emission from the fluorescent species,
wherein the fluorescent species exhibits a first emission intensity at a first emission wavelength and a second emission intensity at a second emission wavelength, the ratio of the first and second emission intensities being dependent on pH, and
wherein the fluorescent species immobilized on the substrate is prepared by covalently coupling a benzo[c]xanthene linker compound to the substrate, wherein the benzo[c]xanthene linker compound
is
its salts, active esters, acid/base forms, and tautomers; and
(b) measuring the first and second emission intensities to determine the pH of the sample.

### Claim 2 (depends on 1)

The method of claim 1, wherein the substrate is a macromolecule.

### Claim 3 (depends on 2)

The method of claim 2, wherein the macromolecule is an albumin.

### Claim 4 (depends on 2)

The method of claim 2, wherein the macromolecule is a human serum albumin.

### Claim 5 (depends on 1)

The method of claim 1, wherein the sample comprises blood or a blood product.

### Claim 6 (depends on 1)

The method of claim 1, wherein the probe is physically isolated from the fluorescent species immobilized on the substrate by a window transparent to the excitation light and the fluorescent emission.

### Claim 7 (depends on 1)

The method of claim 1, wherein the sample is contained within a sealed vessel.

### Claim 8

A system for measuring pH, comprising:
(a) a light source for exciting a fluorescent species immobilized on the substrate, wherein the fluorescent species has a first emission intensity at a first emission wavelength and a second emission intensity at a second emission wavelength,
wherein the fluorescent species immobilized on the substrate is prepared by covalently coupling a benzo[c]xanthene linker compound to the substrate, wherein the benzo[c]xanthene linker compound
is
its salts, active esters, acid/base forms, and tautomers
(b) a first emission detector for measuring the first emission intensity;
(c) a second emission detector for measuring the second emission intensity;
(d) an excitation lightguide for transmitting excitation light from the light source to the fluorescent species, wherein the lightguide comprises a first terminus proximate to the light source and a second terminus distal to the light source;
(e) a first emission lightguide for transmitting emission from the fluorescent species to the first emission detector, wherein the lightguide comprises a first terminus proximate to the detector and a second terminus distal to the detector;
(f) a second emission lightguide for transmitting emission from the fluorescent species to the second emission detector, wherein the lightguide comprises a first terminus proximate to the detector and a second terminus distal to the detector;
(g) a probe housing the distal termini of the excitation lightguide, first emission lightguide, and second emission light guide; and
(h) an assembly for receiving the probe, the assembly comprising:
(i) a housing for receiving the probe, wherein the housing is adapted for receiving the probe at a first end and terminating with a window at the second end, the window being transparent to the excitation and the emission light,
(ii) a tip member reversibly connectable to the housing's second end, wherein the tip member is adapted to receive liquid from a sample to be measured, and
(iii) the fluorescent species immobilized on the substrate intermediate the tip member and the window, wherein the fluorescent species immobilized on the substrate is in liquid communication with the sample during the measurement.

### Claim 9 (depends on 8)

The system of claim 8, wherein substrate is a macromolecule.

### Claim 10 (depends on 9)

The system of claim 9, wherein the macromolecule is an albumin.

### Claim 11 (depends on 9)

The system of claim 9, wherein the macromolecule is a human serum albumin.

### Claim 12 (depends on 8)

The system of claim 8, wherein the probe is physically isolated from the fluorescent species immobilized on the substrate by a window transparent to the excitation light and the fluorescent emission.

### Claim 13 (depends on 8)

The system of claim 8, wherein the light source is a light-emitting diode.

### Claim 14 (depends on 8)

The system of claim 8, wherein the first and second detectors are photodiodes.

### Claim 15 (depends on 8)

The system of claim 8, wherein the sample comprises blood or a blood product.

### Claim 16 (depends on 8)

The system of claim 8, wherein the sample is contained within a sealed vessel.