Apparatus and method for rapid and accurate quantification of an unknown, complex mix
An apparatus and method for rapidly and accurately identifying and quantifying analytes in a complex mixture is disclosed. The apparatus comprises an ultra-sensitive cavity-enhanced spectrometer coupled to data-collection and analysis devices. The method comprises the use of a database containing the absorption cross-sections of various analytes to numerically determine the composition of the sample.
1. An apparatus for identifying and quantifying the presence of least two analytes simultaneously in a liquid or pressure-broadened gas sample comprising:
an infrared light source for emitting infrared light in a plurality of discrete monochromatic frequencies;
a pulse generator for pulsing the infrared light;
a measurement chamber for receiving
the infrared light, and
the sample,
a pressure regulator for regulating pressure within the measurement chamber;
a detector for detecting and measuring the intensity of light attenuation from the chamber, and producing a signal indicative thereof; and
a computer, for receiving the signal and programmed to utilize the signal to simultaneously identify and quantify the at least two analytes.
2. The apparatus of claim 1 , wherein the light is selected from the group consisting of a gas laser, a solid-state laser or a quantum cascade laser.
3. The apparatus of claim 1 wherein the gas tube laser is a CO or CO 2 laser.
4. The apparatus of claim 3 wherein the CO 2 laser is an isotopic CO 2 laser.
5. The apparatus of claim 1 wherein the light source comprises multiple coupled light sources.
6. The apparatus of claim 1 , wherein the plurality of monochromatic frequencies comprises widely-spaced frequencies.
7. The apparatus of claim 1 , wherein the pulse generator is internal or external to the light source.
8. The apparatus of claim 1 , wherein the pulse generator is for modulating the intensity of the light source.
9. The apparatus of claim 1 , wherein the pulse generator is for producing a single or periodic pulses.
10. The apparatus of claim 1 , wherein the pulse generator is an acousto-optic modulator.
11. The apparatus of claim 1 , wherein the measurement chamber is a cavity-enhanced chamber.
12. The apparatus of claim 11 , wherein the cavity-enhanced measurement chamber is a cavity ringdown chamber.
13. The apparatus of claim 12 , wherein the pulsed light source is mode-matched to the cavity ringdown chamber.
14. The apparatus of claim 1 , wherein the detector comprises a photovoltaic semiconductor.
15. The apparatus of claim 1 , wherein the apparatus further comprises sampling equipment for collecting the sample.
16. The apparatus of claim 1 , wherein the apparatus further comprises a temperature regulator for regulating the temperature of the measurement chamber.
17. An apparatus for identifying and quantifying the presence of at least two analytes in a liquid or pressure-broadened gas sample comprising:
a. an isotopic CO 2 infrared laser light source for emitting infrared light in a plurality of discrete, widely-spaced monochromatic frequencies;
b. an acousto-optic modulator for generating pulses of the infrared light,
c. a cavity ringdown measurement chamber for receiving:
the infrared light, and
the sample;
d. a pressure regulator, for regulating pressure within the measurement chamber;
e. a temperature regulator, for regulating temperature within the measurement chamber;
f. a detector, operatively connected to the measurement chamber, for detecting and measuring attenuation of the infrared light from within the chamber, and producing an electronic current proportional thereto; and
g. a computer, operatively connected to the detector and for receiving the electronic current, and programmed to:
i. utilize the electronic current to calculate and produce an absorption spectrum of the sample, and
ii, compare the absorption spectrum to known analyte absorption cross sections to simultaneously identify and quantify the at least two analytes in the sample.
18. A method for identifying and quantifying the presence of at least two analytes simultaneously in a liquid or pressure-broadened gas sample, the method comprising:
a. providing an infrared light source for emitting infrared light in a plurality of pulsed, discrete monochromatic frequencies,
b. providing a measurement chamber for receiving the light and the sample, wherein the temperature and pressure within the chamber are regulated,
c. providing the sample to the measurement chamber,
d. providing the light to the chamber,
e. measuring and determining the absorption for the at least two analytes at each monochromatic frequency and producing an absorption spectrum thereof, and
f. comparing the determined absorption spectrum with known absorptions cross-sections simultaneously to identify and quantify the at least two analytes.
19. The method of claim 18 , wherein the light source is selected from the group consisting of a gas laser, a solid-state laser or a quantum cascade laser.
20. The method of claim 19 , wherein the gas laser is a CO or CO 2 laser.
21. The method of claim 20 , wherein the CO 2 laser is an isotopic CO 2 laser.
22. The method of claim 18 , wherein the light source comprises multiple coupled light sources.
23. The method of claim 18 , wherein the plurality of monochromatic frequencies comprises widely-spaced frequencies.
24. The method of claim 18 , wherein the infrared light is emitted in a single pulse or periodic pulses.
25. The method of claim 18 , wherein the measurement chamber is a cavity-enhanced chamber.
26. The method of claim 25 , wherein the cavity-enhanced measurement chamber is a cavity ringdown chamber.
27. The method of claim 26 , wherein the pulsed light source is mode-matched to the cavity ringdown chamber.