CONCENTRATION MEASUREMENT USING LUMINESCENCE

• US 20130256562A1
• Filed: 07/19/2011
• Published: 10/03/2013
• Est. Priority Date: 07/19/2010
• Status: Active Grant

• Current Assignee: Oxford Optronix Ltd.
• Original Assignee: Oxford Optronix Ltd.
• Inventors: Ward, Geoffrey
• Granted Patent: US 9,207,176 B2
• Time in Patent Office: Days
• US Class Current: 250/459.1
• CPC Class Codes: G01N 2021/641 Phosphorimetry, gated
• CPC Class Codes: G01N 2021/6413 Distinction short and delayed fluorescence or phosphorescence
• CPC Class Codes: G01N 2021/6434 Optrodes
• CPC Class Codes: G01N 2021/6484 Optical fibres
• CPC Class Codes: G01N 2021/772 Tip coated light guide
• CPC Class Codes: G01N 2021/773 Porous polymer jacket; Polymer matrix with indicator
• CPC Class Codes: G01N 2021/7786 Fluorescence
• CPC Class Codes: G01N 21/64 Fluorescence; Phosphorescence
• 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 21/7703 using reagent-clad optical fibres or optical waveguides using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B

Abstract

A method of measuring the concentration of a substance, using a sensor (2) comprising a luminescent material, an LED light source (14) which supplies a pulse of light to the sensor to cause luminescence of the material, a detector (26) for detecting the emitted light and a data processing module (28) for analysing the signals and indicating the concentration of the substance. In a measuring sequence there is a series of pulses of light spaced apart sufficiently to permit the luminescence to decay between pulses. The signals which are analysed are those generated after each pulse of light has terminated and the luminescence is decaying. The data processing module (28) comprises a plurality of accumulators (52A, 52B, 52C and 52D) which are controlled to be operable over a corresponding plurality of different periods of time during decay of the luminescence. Each accumulator accumulates values indicative of the intensity of the luminescence from the series of pulses in the measuring sequence. The parameters regarding the accumulators are stored in a configuration memory (42) which is part of the sensor.

Claims

1. A method of measuring the concentration of a substance, using a sensor comprising a luminescent material having a luminescent activity whose characteristics depend on the concentration of the substance, a light source which supplies a pulse of light to the sensor for a period of time sufficient to cause luminescence of the luminescent material, the luminescence rising to a peak and then decaying after the end of the pulse of light, a detector for detecting the light emitted by the luminescence of the luminescent material and generating signals in response thereto, and a data processing module for analysing the signals and for providing data indicative of the concentration of the substance;

wherein in a measuring sequence there is a series of pulses of light spaced apart sufficiently to permit the luminescence to decay between pulses, the signals which are analysed to provide the data indicative of the concentration of the substance are those generated after each pulse of light has terminated and the luminescence is decaying, and wherein the data processing module comprises a plurality of accumulators which are controlled to be operable over a corresponding plurality of different periods of time during the decay of the luminescence, each accumulator accumulating values indicative of the intensity of the luminescence from the series of pulses in the measuring sequence.

2. A method as claimed in claim 1, wherein for each accumulator the accumulator value is sampled at intervals during the measurement sequence, and the values are processed to provide a slope which is used in determination of the substance concentration.

3. A method as claimed in claim 1, wherein the data processing module comprises two channels, each of which comprises a plurality of said accumulators which are controlled to be operable over a corresponding plurality of different periods of time during decay of the luminescence, each accumulator accumulating values indicative of the intensity of the luminescence from the series of pulses in the measuring sequence;

and wherein the measuring sequences are alternated between the two channels, the accumulators in one channel being reset after the end of the measuring sequence using that channel, whilst a measuring sequence is carried out using the other channel.

4. A method as claimed in claim 1, wherein there are at least four accumulators, controlled to be operable over a corresponding number of different periods during the decay of the luminescence.

5. A method as claimed in claim 3 wherein in each channel there are at least four accumulators, controlled to be operable over a corresponding number of different periods during the decay of the luminescence.

6. A method as claimed in claim 1, wherein there are first and second accumulators which are timed to be active whilst the luminescence is decaying relatively steeply, the first accumulator being active over a first period of time and the second accumulator being active over an adjacent period of time which commences on, or a relatively short time after, the end of the first period of time.

7. A method as claimed in claim 6, wherein there is a third accumulator which is active over a third period of time, which commences a relatively long time after the end of the second period of time, when there is a substantially less steep rate of decay of the luminescence than during the first and second periods of time.

8. A method as claimed in claim 7, wherein there is a fourth accumulator which is active over a fourth period of time, which commences a relatively long time after the end of the third period of time.

9. A method as claimed in claim 1, wherein each accumulator is operable for a period which is less than 5 microseconds during the decay of the luminescence.

10. A method as claimed in claim 1, wherein the periods of time over which the respective accumulators are operable are of substantially equal duration.

11. A method as claimed in claim 1, wherein the periods over which the respective accumulators are active are determined by parameters stored in a configuration memory.

12. A method as claimed in claim 11, wherein the configuration parameters are stored in a configuration memory which is part of the sensor, and when the sensor is connected to the control unit, a connection is made with the configuration memory, and the configuration parameters are read and used by the data processing module.

13. A method as claimed in claim 12, wherein the configuration memory which is part of the sensor stores, in addition to the configuration parameters, the energy and/or time exposure of the sensor.

14. A method as claimed in claim 13, wherein the configuration memory which is part of the sensor stores, in addition, any or all of:

the allowed amount of energy or time exposure;

the date of calibration of the sensor;

the allowed period of time from the date of calibration of the sensor;

the date of first use of the sensor;

the allowed period of time from the date of first use of the sensor;

the number of times that the sensor has been used;

the allowed number of times that the sensor may be used;

sensor identification information sensor configuration information;

the units of measurement for the assay substance;

light pulsing and accumulator timings;

minimum and maximum acceptable luminescent lifetimes;

minimum and maximum acceptable sensor temperatures;

minimum and maximum acceptable assay concentrations; and

sensor dye and temperature calibration information.

15. A method as claimed in claim 12, wherein the sensor also incorporate a temperature measuring device.

16. A method as claimed in claim 15, wherein the configuration memory also stores any or all of the following data:

Minimum and maximum un-calibrated cold junction temperatures;

Minimum and maximum calibrated cold junction temperatures;

Cold junction calibration information;

Minimum and maximum thermocouple voltages;

Minimum and maximum calibrated thermocouple temperatures;

Thermocouple calibration information.

21. A method as claimed in claim 2, wherein each accumulator accumulates a value indicative of the intensity of the luminescence after a pulse of light and accumulates the values from the series of pulses in the measuring sequence.

22. A method as claimed in claim 3, wherein each accumulator accumulates a value indicative of the intensity of the luminescence after a pulse of light and accumulates the values from the series of pulses in the measuring sequence.

17. Apparatus for measuring the concentration of a substance, comprising a sensor comprising a luminescent material having a luminescent activity whose characteristics depend on the concentration of the substance, a light source which supplies a pulse of light to the sensor for a period of time sufficient to cause luminescence of the luminescent material, the luminescence rising to a peak and then decaying after the end of the pulse of light, a detector for detecting the light emitted by the luminescence of the luminescent material and generating signals in response thereto, and a data processing module for analysing the signals and for providing data indicative of the concentration of the substance;

wherein the data processing module is configured so that in a measuring sequence there is a series of pulses of light spaced apart sufficiently to permit the luminescence to decay between pulses, the signals which are analysed to provide the data indicative of the concentration of the substance are those generated after each pulse of light has terminated and the luminescence is decaying, and wherein the data processing module comprises a plurality of accumulators which are controlled to be operable over a corresponding plurality of different periods of time during decay of the luminescence, each accumulator accumulating values indicative of the intensity of the luminescence from the series of pulses in the measuring sequence.

18. A non-transitory computer-readable medium having stored thereon instructions for configuring a data processing module of apparatus for measuring the concentration of a substance, the apparatus comprising a sensor comprising a luminescent material having a luminescent activity whose characteristics depend on the concentration of the substance, a light source which supplies a pulse of light to the sensor for a period of time sufficient to cause luminescence of the luminescent material, the luminescence rising to a peak and then decaying after the end of the pulse of light, and a detector for detecting the light emitted by the luminescence of the luminescent material and generating signals in response thereto, the data processing module being for analysing the signals and for providing data indicative of the concentration of the substance;

wherein the non-transitory computer-readable medium contains instructions which when run on the data processing module will cause the data processing module to operate so that in a measuring sequence there is a series of pulses of light spaced apart sufficiently to permit the luminescence to decay between pulses, the signals which are analysed to provide the data indicative of the concentration of the substance are those generated after each pulse of light has terminated and the luminescence is decaying, and wherein the data processing module comprises a plurality of accumulators which are controlled to be operable over a corresponding plurality of different periods of time during decay of the luminescence, each accumulator accumulating values indicative of the intensity of the luminescence from the series of pulses in the measuring sequence.

19-20. -20. (canceled)