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Signal-to-Noise Enhancement of a Nanospring Redox-Based Sensor by Lock-in Amplification.

Bakharev PV, McIlroy DN - Sensors (Basel) (2015)

Bottom Line: A significant improvement of the response characteristics of a redox chemical gas sensor (chemiresistor) constructed with a single ZnO coated silica nanospring has been achieved with the technique of lock-in signal amplification.However, at 10 ppm the signal-to-noise ratio is 5 dB, which is less than desirable.When operated in the analog LIA mode, the signal-to-noise ratio at 10 ppm increases by 30 dB and extends the detection limit to the ppb range.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, University of Idaho, Moscow, ID 83844, USA. bakharevpavel@gmail.com.

ABSTRACT
A significant improvement of the response characteristics of a redox chemical gas sensor (chemiresistor) constructed with a single ZnO coated silica nanospring has been achieved with the technique of lock-in signal amplification. The comparison of DC and analog lock-in amplifier (LIA) AC measurements of the electrical sensor response to toluene vapor, at the ppm level, has been conducted. When operated in the DC detection mode, the sensor exhibits a relatively high sensitivity to the analyte vapor, as well as a low detection limit at the 10 ppm level. However, at 10 ppm the signal-to-noise ratio is 5 dB, which is less than desirable. When operated in the analog LIA mode, the signal-to-noise ratio at 10 ppm increases by 30 dB and extends the detection limit to the ppb range.

No MeSH data available.


Related in: MedlinePlus

The electrical response of a single ZnO coated nanospring device measured at lock-in amplifier (LIA) output upon exposure to toluene vapor at (a) 60 ppm; (b) 40 ppm; (c) 20 ppm and (d) 10 ppm.
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sensors-15-13110-f004: The electrical response of a single ZnO coated nanospring device measured at lock-in amplifier (LIA) output upon exposure to toluene vapor at (a) 60 ppm; (b) 40 ppm; (c) 20 ppm and (d) 10 ppm.

Mentions: The electrical response of a single ZnO coated nanospring chemiresistor measured at LIA output to toluene vapor pulses at 60 ppm, 40 ppm, 20 ppm and 10 ppm is displayed in Figure 4. The LIA chemiresistor signals in Figure 4 are superior to the DC signals in Figure 2. The contribution of noise to the signal of the chemiresistor in LIA mode is practically negligible down to 20 ppm. At 10 ppm of toluene the signal of the chemiresistor operated in the DC mode is not trustworthy. By contrast, when operated in LIA mode, the chemiresistor signal at 10 ppm is as reliable as that at 60 ppm. Note, there is no loss of information with regards to the amplitude of the signal when operated in the LIA mode. The utilization of the LIA technique significantly improves not only the electrical response characteristics of a single ZnO coated nanospring sensor (receptor), but also considerably expands the recognition capabilities of the gas sensor array (electronic nose) in the frames of linear discrimination analysis (LDA), independent component analysis (ICA), principal component analysis (PCA) and other multiple odor recognition methods [9,11,32,33,34]. The repeatability of the signal profile and intensity will greatly increase the reliability of LDA-based detection.


Signal-to-Noise Enhancement of a Nanospring Redox-Based Sensor by Lock-in Amplification.

Bakharev PV, McIlroy DN - Sensors (Basel) (2015)

The electrical response of a single ZnO coated nanospring device measured at lock-in amplifier (LIA) output upon exposure to toluene vapor at (a) 60 ppm; (b) 40 ppm; (c) 20 ppm and (d) 10 ppm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507677&req=5

sensors-15-13110-f004: The electrical response of a single ZnO coated nanospring device measured at lock-in amplifier (LIA) output upon exposure to toluene vapor at (a) 60 ppm; (b) 40 ppm; (c) 20 ppm and (d) 10 ppm.
Mentions: The electrical response of a single ZnO coated nanospring chemiresistor measured at LIA output to toluene vapor pulses at 60 ppm, 40 ppm, 20 ppm and 10 ppm is displayed in Figure 4. The LIA chemiresistor signals in Figure 4 are superior to the DC signals in Figure 2. The contribution of noise to the signal of the chemiresistor in LIA mode is practically negligible down to 20 ppm. At 10 ppm of toluene the signal of the chemiresistor operated in the DC mode is not trustworthy. By contrast, when operated in LIA mode, the chemiresistor signal at 10 ppm is as reliable as that at 60 ppm. Note, there is no loss of information with regards to the amplitude of the signal when operated in the LIA mode. The utilization of the LIA technique significantly improves not only the electrical response characteristics of a single ZnO coated nanospring sensor (receptor), but also considerably expands the recognition capabilities of the gas sensor array (electronic nose) in the frames of linear discrimination analysis (LDA), independent component analysis (ICA), principal component analysis (PCA) and other multiple odor recognition methods [9,11,32,33,34]. The repeatability of the signal profile and intensity will greatly increase the reliability of LDA-based detection.

Bottom Line: A significant improvement of the response characteristics of a redox chemical gas sensor (chemiresistor) constructed with a single ZnO coated silica nanospring has been achieved with the technique of lock-in signal amplification.However, at 10 ppm the signal-to-noise ratio is 5 dB, which is less than desirable.When operated in the analog LIA mode, the signal-to-noise ratio at 10 ppm increases by 30 dB and extends the detection limit to the ppb range.

View Article: PubMed Central - PubMed

Affiliation: Department of Physics, University of Idaho, Moscow, ID 83844, USA. bakharevpavel@gmail.com.

ABSTRACT
A significant improvement of the response characteristics of a redox chemical gas sensor (chemiresistor) constructed with a single ZnO coated silica nanospring has been achieved with the technique of lock-in signal amplification. The comparison of DC and analog lock-in amplifier (LIA) AC measurements of the electrical sensor response to toluene vapor, at the ppm level, has been conducted. When operated in the DC detection mode, the sensor exhibits a relatively high sensitivity to the analyte vapor, as well as a low detection limit at the 10 ppm level. However, at 10 ppm the signal-to-noise ratio is 5 dB, which is less than desirable. When operated in the analog LIA mode, the signal-to-noise ratio at 10 ppm increases by 30 dB and extends the detection limit to the ppb range.

No MeSH data available.


Related in: MedlinePlus