SWEPT FREQUENCY FLUOROMETER

Abstract

A swept frequency fluorometer having a signal processor or processing module configured to:

receive signaling containing information about reflected light off one or more fluorescence species-of-interest in a liquid sample that is swept with light having a variable frequency range, the information including a characteristic optical frequency corresponding to a fluorescence species-of-interest in the liquid, and a characteristic/lifetime optical frequency corresponding to a distinct fluorescence lifetime in which the fluorescence species-of-interest remains in an excited state; and

provide corresponding signaling containing information about an identity of the fluorescence species-of-interest detected and distinguished from overlapping fluorescence species in the liquid using the characteristic/lifetime optical frequency, based upon the signaling received

Claims

1. Apparatus comprising: a signal processor or processing module configured to: receive signaling containing information about reflected light off one or more fluorescence species-of-interest in a liquid sample that is swept with light having a variable frequency range, the information including a characteristic optical frequency corresponding to a fluorescence species-of-interest in the liquid, and a characteristic/lifetime optical frequency corresponding to a distinct fluorescence lifetime in which the fluorescence species-of-interest remains in an excited state; and provide corresponding signaling containing information about an identity of the fluorescence species-of-interest detected and distinguished from overlapping fluorescence species in the liquid using the characteristic/lifetime optical frequency, based upon the signaling received

2. Apparatus according to claim 1, wherein the apparatus comprises a light sensor configured to sense the light across the variable frequency range, and provide the signaling.

3. Apparatus according to claim 2, wherein the light sensor is a linear sensor array configured to sense the light across the variable frequency range along the length of a light source providing the light.

4. Apparatus according to claim 1, wherein the apparatus comprises a light source configured to sweep excitation light having an excitation optical wavelength across the variable frequency range to excite the one or more fluorescence species-of-interest.

5. Apparatus according to claim 4, wherein the light source is a swept-frequency light source, including a quasi-collimated light source.

6. Apparatus according to claim 1, wherein the variable frequency range includes a lock-in frequency that is swept by gradually increasing excitation light from an initial modulation frequency f.sub.i to a final modulation frequency f.sub.f.

7. Apparatus according to claim 1, wherein the variable frequency range includes a mid-point frequency that corresponds to the characteristic/lifetime optical frequency.

8. Apparatus according to claim 1, wherein the apparatus is a swept frequency fluorometer.

9. A method, comprising: receiving, with a signal processor or processing module, signaling containing information about reflected light off one or more fluorescence species-of-interest in a liquid sample that is swept with light having a variable frequency range, the information including a characteristic optical frequency corresponding to a fluorescence species-of-interest in the liquid, and a characteristic/lifetime optical frequency corresponding to a distinct fluorescence lifetime in which the fluorescence species-of-interest remains in an excited state; and providing, with the signal processor or processing module, corresponding signaling containing information about an identity of the fluorescence species-of-interest detected and distinguished from overlapping fluorescence species in the liquid using the characteristic/lifetime optical frequency, based upon the signaling received.

10. A method according to claim 9, wherein the method comprises configuring a light sensor to sense the light across the variable frequency range, and provide the signaling.

11. A method according to claim 10, wherein the method comprises configuring the light sensor as a linear sensor array to sense the light across the variable frequency range along the length of a light source providing the light.

12. A method according to claim 9, wherein the method comprises configuring a light source to sweep excitation light having an excitation optical wavelength across the variable frequency range to excite the one or more fluorescence species-of-interest.

13. A method according to claim 12, wherein the method comprises configuring the light source as a swept-frequency light source, including a quasi-collimated light source.

14. A method according to claim 9, wherein the variable frequency range includes a lock-in frequency that is swept by gradually increasing excitation light from an initial modulation frequency f.sub.i to a final modulation frequency f.sub.f.

15. A method according to claim 9, wherein the variable frequency range includes a mid-point frequency that corresponds to the characteristic/lifetime optical frequency.

16. A method according to claim 9, wherein the method comprises configuring the signal processor or signal processing module as part of a swept frequency fluorometer.

17. A swept frequency fluorometer comprising: a light source configured to provide light on a liquid sample having one or more fluorescence species-of-interest, the light having a variable frequency range with an initial frequency f.sub.i and a final frequency of f.sub.f; a light sensor configured to sense reflected light off the fluorescence species-of-interest in the liquid sample and provide signaling containing information about the reflected light off the one or more fluorescence species-of-interest in the liquid sample that is swept with the light having the variable frequency range, the information including a characteristic optical frequency corresponding to a fluorescence species-of-interest in the liquid, and a characteristic/lifetime optical frequency corresponding to a distinct fluorescence lifetime in which the fluorescence species-of-interest remains in an excited state; and a signal processor or processing module configured to: receive the signaling, and provide corresponding signaling containing information about an identity of the fluorescence species-of-interest detected and distinguished from overlapping fluorescence species in the liquid using characteristic/lifetime optical frequency, based upon the signaling received.

18. A swept frequency fluorometer according to claim 19, wherein the light source is a swept-frequency light source, including a quasi-collimated light source; and the light sensor is a linear sensor array configured to sense the light across the variable frequency range along the length of a light source providing the light.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0035] The drawing, which are not necessarily drawn to scale, includes FIGS. 1-5, as follows:

[0036] FIG. 1 is a graph of excitation, emission and fluorescence lifetime, and provides a concept plot of the fluorometer according to the present invention, in which three different, but overlapping species can be measured within the same Ex/Em band pass region. Traditional fluorometers do not have the ability to distinguish between the three species, but with the rendering of fluorescence lifetime, a distinction can be made according to the present invention.

[0037] FIG. 2 includes FIGS. 2A and 2B and is an Excitation Emission Matrix (EEM) plot of two overlapping species (TrisBipy Ru (II) and Pt Porphyrin). For clarity, the plots are stacked (not overlaid). The axes and scale are the same in both frames.

[0038] FIG. 3 is a graph or plot of relative phase angle (Deg.) vs. swept modulation excitation frequency (Hz) of the respective species (TrisBipy Ru (II) and Pt Porphyrin), e.g., showing how the phase responses are completely distinguishable though their respective EEM signatures occupy the same region of the EEM chart, causing ambiguity.

[0039] FIG. 4 is a block diagram of a swept frequency fluorometer, e.g., having a light source, a light sensor and a signal processor or processing module for performing signal processing functionality, according to some embodiments of the present invention.

[0040] FIG. 5 is a diagram of the light sensor in the form of a linear sensor array, e.g., having rows and columns of optical elements, according to some embodiments of the present invention.

[0041] To reduce clutter in the drawing, each Figure in the drawing does not necessarily include every reference label for every element shown therein.

DETAILED DESCRIPTION OF BEST MODE OF THE INVENTION

[0042] FIG. 4 shows apparatus 10, including a swept frequency fluorometer, according to the present invention, e.g., having a light source 20 such as quasi-collimated light source, a light sensor 30 such as a linear sensor array, and a signal processor or processing module 40.

[0043] The light source 20 may be configured to provide light on a liquid sample having one or more fluorescence species-of-interest, the light having a variable frequency range with an initial frequency f.sub.i and a final frequency f.sub.f. According to some embodiments, the light source 20 may be configured to respond to a light source control signal, e.g., provided by the signal processor or processing module 40 and provide the light having the variable frequency range.

[0044] The light sensor 30 may be configured to sense reflected light off the fluorescence species-of-interest in the liquid sample and provide signaling containing information about the reflected light off the one or more fluorescence species-of-interest in the liquid sample that is swept with the light having the variable frequency range, the information including a characteristic optical frequency corresponding to a fluorescence species-of-interest in the liquid, and a characteristic/lifetime optical frequency corresponding to a distinct fluorescence lifetime in which the fluorescence species-of-interest remains in an excited state. According to some embodiments, the light sensor 30 may be configured to respond to a light sensor control signal, e.g., provided by the signal processor or processing module 40 and sense the reflected light.

[0045] The signal processor or processing module 40 may be configured to [0046] receive the signaling; and [0047] provide corresponding signaling containing information about an identity of the fluorescence species-of-interest detected and distinguished from overlapping fluorescence species in the liquid using the characteristic/lifetime optical frequency, based upon the signaling received.
According to some embodiments, the signal processor or processing module 40 may be configured to provide the light source control signal and/or the light sensor control signal, e.g., to the light source 20 and/or light sensor 30.

The Light Source 20

[0048] By way of example, the light source 20 may be configured to provide the light, including quasi-collimated light, along a corresponding length of the linear sensor array 30, e.g., as shown in FIG. 5, through a liquid sample arranged in relation to the light source 20 and the linear sensor array 30 so as to reflect the light off the one or more fluorescence species-of-interest in the liquid sample being monitored or tested onto the linear sensor array 30.

[0049] As a person skilled in the art would appreciate, quasi-collimated light sources are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind thereof either now known or later developed in the future.

The Linear Sensor Array 30

[0050] By way of example, the linear sensor array 30 may include, e.g., a linear photodiode array, a linear charge-coupled device (CCD) array, or a linear CMOS array. In particular, the linear sensor array 30 may include a two-dimensional array of rows and columns of optical elements (r1, c1; r1, c2; r1, c3; r1, c4; r1, c5; r1, c6; r1, c7; r1, c8; . . . ; r1, cn; r2, c1; r2, c2; r2, c3; r2, c4; r2, c5; r2, c6; r2, c7; r2, c8; . . . ; r2, cn; r3, c1; r3, c2; r3, c3; r3, c4; r3, c5; r3, c6; r3, c7; r3, c8; . . . ; r3, cn; . . . ; rn, c1; rn, c2; rn, c3; rn, c4; rn, c5; rn, c6; rn, c7; rn, c8; . . . ; rn, cn) like that shown in FIG. 5, e.g., that are individually addressable. Linear sensor arrays are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind thereof either now known or later developed in the future.

[0051] By way of example, linear sensors arrays are disclosed in the following U.S. Pat. Nos. 9,020,202; 8,022,349; 7,956,341; 7,040,538; 5,252,818; and 4,193,057, which are all hereby incorporated by reference.

The Signal Processor or Processing Module 40

[0052] By way of example, the signal processor or processing module 40 may be configured to determine the one or more fluorescence species-of-interest based upon the frequencies so determined, and then determine the concentration of turbidity of the liquid, based upon the same. Techniques for processing signaling containing information about sensed optical frequencies, e.g., in relation to the concentration of turbidity in the liquid, are known in the art, and the scope of the invention is not intended to be limited to any particular type or kind thereof either now known or later developed in the future.

Implementation of Signal Processing Functionality

[0053] By way of example, the functionality of the signal processor or processing module 40 may be implemented using hardware, software, firmware, or a combination thereof. In a typical software implementation, the signal processor 40 would include one or more microprocessor-based architectures having, e. g., at least one signal processor or microprocessor. One skilled in the art would be able to program with suitable program code such a microcontroller-based, or microprocessor-based, implementation to perform the signal processing functionality disclosed herein without undue experimentation.

[0054] The scope of the invention is not intended to be limited to any particular implementation using technology either now known or later developed in the future. The scope of the invention is intended to include implementing the functionality of the signal processor(s) as stand-alone processor, signal processor, or signal processor module, as well as separate processor or processor modules, as well as some combination thereof.

[0055] By way of example, the apparatus 10 may also include, e.g., other signal processor circuits or components generally indicated 50, including random access memory or memory module (RAM) and/or read only memory (ROM), input/output devices and control, and data and address buses connecting the same, and/or at least one input processor and at least one output processor, e.g., which would be appreciate by one skilled in the art.

[0056] By way of further example, the signal processor may include, or take the form of, some combination of a signal processor and at least one memory including a computer program code, where the signal processor and at least one memory are configured to cause the system to implement the functionality of the present invention, e.g., to respond to signaling received and to determine the corresponding signaling, based upon the signaling received.

The Scope of the Invention

[0057] While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made, and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed herein as the best mode contemplated for carrying out this invention.