Dual output acoustic wave sensor for molecular identification
First Claim
1. A method for the identification and quantification of sorbed chemical species onto a coating of a device capable of generating and receiving an acoustic wave, comprising:
- (a) measuring the changes in the velocity of the acoustic wave resulting from the sorption of the chemical species into the coating as the wave travels through the coating;
(b) measuring the changes in the attenuation of an acoustic wave resulting from the sorption of the chemical species into the coating as the wave travels through the coating;
(c) correlating the magnitudes of the changes of velocity with respect to changes of the attenuation of the acoustic wave to identify the sorbed chemical species.
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Accused Products
Abstract
A method of identification and quantification of absorbed chemical species by measuring changes in both the velocity and the attenuation of an acoustic wave traveling through a thin film into which the chemical species is sorbed. The dual output response provides two independent sensor responses from a single sensing device thereby providing twice as much information as a single output sensor. This dual output technique and analysis allows a single sensor to provide both the concentration and the identity of a chemical species or permits the number of sensors required for mixtures to be reduced by a factor of two.
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Citations
48 Claims
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1. A method for the identification and quantification of sorbed chemical species onto a coating of a device capable of generating and receiving an acoustic wave, comprising:
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(a) measuring the changes in the velocity of the acoustic wave resulting from the sorption of the chemical species into the coating as the wave travels through the coating; (b) measuring the changes in the attenuation of an acoustic wave resulting from the sorption of the chemical species into the coating as the wave travels through the coating; (c) correlating the magnitudes of the changes of velocity with respect to changes of the attenuation of the acoustic wave to identify the sorbed chemical species. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An apparatus for detecting and identifying at least one unknown chemical species, comprising:
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(a) an acoustic wave device capable of generating, transmitting and receiving an acoustic wave, said device coated with a material, said material having properties which change upon sorption of a chemical species; (b) means for measuring the velocity of an acoustic wave travelling through said material; (c) means for simultaneously measuring the attenuation of the acoustic wave traveling through said coating material; (d) sampling means to contact said acoustic wave device to said unknown chemical species for sorption of said unknown chemical species into said coating material; (e) means for determining the changes in both the attenuation and velocity values of said acoustic wave upon sorption of said unknown chemical species into said coating material; and (f) means for correlating the magnitudes of the changes of velocity with respect to the changes of the attenuations of the acoustic wave; and (g) means for comparing the values of the velocity and attenuation changes to known values of velocity and attenuation of known chemical species in order to identify said unknown sorbed chemical species. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46)
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47. An apparatus for detecting and identifying at least one unknown chemical species, comprising:
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(a) at least one acoustic wave device, wherein said acoustic wave device comprises a piezoelectric substrate having two interdigitated transducers at opposing ends of said substrate, one of said transducers to generate an acoustic wave, and the other of said transducers to receive an acoustic wave as said wave is transmitted through said piezoelectric substrate and to generate a signal having a frequency of said acoustic wave in response thereto, said substrate coated with a material, said material having properties which change upon sorption of a chemical species; (b) an oscillator loop to measure the velocity of an acoustic wave traveling through said material, said loop further comprising a first coupler electrically connected to said acoustic wave device to direct a fraction of said signal'"'"'s power into a first and second path, a RF amplifier electrically connected along said first path to said first coupler to amplify said signal, a directional coupler electrically connected to said first path to direct a portion of said signal along said first path and along a third path, a frequency counter electrically connected along said third path to said directional coupler, said frequency counter to measure a frequency shift (Δ
f) of said signal which is related to the velocity shift (Δ
v) of said wave as it travels through said material by Δ
f/fo =KΔ
v/vo where K is the fraction of the acoustic wave path covered by said material sorbing said unknown chemical species and vo and fo are the unperturbed velocity and frequency, respectively, a second coupler electrically connected along said first path to said directional coupler to direct a portion of said signal along said first path into said acoustic wave device and along a fourth path, and a bandpass filter electrically connected along said first path between said directional coupler and said RF amplifier, to filter the signal(c) a vector voltmeter electrically connected between said first and second couplers along said second and fourth paths to divide said signal at said output transducer and to divide said signal at said input transducer, respectively, for measuring the power level of said signal which power level is proportional to the attenuation of power of said wave traveling through said material; (d) sampling means to contact said acoustic wave device to said unknown chemical species for sorption of said unknown chemical species into said coating material; (e) microprocessing means for acquiring data indicating changes in and storing the values of said changes of both the attenuation and velocity values of said acoustic wave upon sorption of said unknown chemical species; (f) a microprocessing analysis means for comparing the values of the velocity and attenuation changes to known values of known chemical species in order to identify said unknown sorbed chemical species; and (g) microprocessing comparing means for comparing the absolute value of the changes in the velocity response to known values of known chemical species in order to determine the concentration of said unknown sorbed chemical species.
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48. A method for the identification and quantification of sorbed chemical species into a coating of a device capable of generating, transmitting and receiving an acoustic wave, comprising:
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(a) measuring the changes in the velocity of the acoustic wave resulting from the sorption of the chemical species into the coating as the wave travels through the coating; (b) measuring the changes in the attenuation of an acoustic wave resulting from the sorption of the chemical species into the coating as the wave travels through the coating; (c) correlating the magnitudes of the changes of velocity with respect to changes of the attenuation of the acoustic wave to identify the sorbed chemical species. (d) correlating the absolute magnitude of the velocity changes to the concentration of the identified chemical species.
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Specification