Analyte Discrimination from Chemiresistor Response Kinetics
7
Citation
20
Reference
10
Related Paper
Citation Trend
Abstract:
Chemiresistors are polymer-based sensors that transduce the sorption of a volatile organic compound into a resistance change. Like other polymer-based gas sensors that function through sorption, chemiresistors can be selective for analytes on the basis of the affinity of the analyte for the polymer. However, a single sensor cannot, in and of itself, discriminate between analytes, since a small concentration of an analyte that has a high affinity for the polymer might give the same response as a high concentration of another analyte with a low affinity. In this paper we use a field-structured chemiresistor to demonstrate that its response kinetics can be used to discriminate between analytes, even between those that have identical chemical affinities for the polymer phase of the sensor. The response kinetics is shown to be independent of the analyte concentration, and thus the magnitude of the sensor response, but is found to vary inversely with the analyte's saturation vapor pressure. Saturation vapor pressures often vary greatly from analyte to analyte, so analysis of the response kinetics offers a powerful method for obtaining analyte discrimination from a single sensor.Keywords:
Chemiresistor
Saturation (graph theory)
Gas sensor with high molecular selectivity is highly demanded in many fields of industry or disaster relief. Molecularly imprinted polymer (MIP) can recognize target gas by specific adsorption for template molecule. In this study, a novel chemiresistor, gas sensor which combined with MIP and conductive nanoparticles has been developed. The gases were distinguished based on molecularly structure by MIP. If gas molecule is absorbed into this polymer, structures and properties of conductive composites are changed. It causes electric resistance changed. It is conceivable that the degree of resistance change is dependent upon the amount of absorption. Moreover, MIP absorbs larger quantity of template molecule than similar gas molecule. So this MIP chemiresistor can be used for measurement of specific target gas based on magnitude of response. Measurement results of gas sensing showed that larger response was produced by MIP chemiresistor for the template molecule than other gas and NIP (non-imprinted polymer) composite. It means that a sensor which could both recognizing molecules and transduce electrical signal simultaneously was successfully developed.
Chemiresistor
Molecularly imprinted polymer
NIP
Cite
Citations (2)
Chemiresistor
Chemical sensor
Cite
Citations (61)
A method to enhance the gold nanoparticle sensor response to weak analytes is demonstrated by pre-exposing the sensor to an analyte which elicits a strong response. This weak analyte effectively reduces the strong analyte interaction with the sensor.
Chemiresistor
Response time
Cite
Citations (2)
We investigate the response dynamics of 1-hexanethiol-functionalized gold nanoparticle chemiresistors exposed to the analyte octane in aqueous solution. The dynamic response is studied as a function of the analyte-water flow velocity, the thickness of the gold nanoparticle film and the analyte concentration. A theoretical model for analyte limited mass-transport is used to model the analyte diffusion into the film, the partitioning of the analyte into the 1-hexanethiol capping layers and the subsequent swelling of the film. The degree of swelling is then used to calculate the increase of the electron tunnel resistance between adjacent nanoparticles which determines the resistance change of the film. In particular, the effect of the nonlinear relationship between resistance and swelling on the dynamic response is investigated at high analyte concentration. Good agreement between experiment and the theoretical model is achieved.
Chemiresistor
Cite
Citations (18)
Chemiresistor
Cite
Citations (13)
Cite
Citations (5)
Chemiresistors are gas sensors for volatile organic compounds that are composed of conducting particle networks in a polymer matrix. In the presence of an analyte that is compatible with the polymer phase, the sensor conductance decreases as the analyte is absorbed, eventually reaching a steady-state value that is a measure of the analyte's concentration. The response curve, which is the relationship between steady-state conductance and analyte activity (normalized concentration), is strongly dependent on both the chemical affinity of the analyte for the polymer and the stress field within the chemiresistor composite. Calibration of an individual sensor would seem to necessitate mapping out the response curve for each analyte of interest, a tedious and expensive proposition. In a recent paper, we have shown that the transduction curve of any particular sensor is a function of polymer swelling alone, regardless of the chemical nature of the analyte. This master transduction curve implies that sensor calibration requires only a knowledge of the polymer mass-sorption isotherm for any set of analytes of interest, data that can be collected once and for all. Any single analyte can then be used to calibrate the response of a particular sensor as a function of analyte activity, and the response to other analytes can be predicted. As a corollary, a calibrated sensor can be used to determine the mass-sorption data for any other analyte of interest. In this paper, we provide a detailed description of the construction of the master transduction curve, show how this curve can be used to measure polymer sorption with a calibrated chemiresistor, and demonstrate the use of a single analyte to calibrate sensors of disparate sensitivities and predict their response to two other analytes.
Chemiresistor
Cite
Citations (5)
Chemiresistors are polymer-based sensors that transduce the sorption of a volatile organic compound into a resistance change. Like other polymer-based gas sensors that function through sorption, chemiresistors can be selective for analytes on the basis of the affinity of the analyte for the polymer. However, a single sensor cannot, in and of itself, discriminate between analytes, since a small concentration of an analyte that has a high affinity for the polymer might give the same response as a high concentration of another analyte with a low affinity. In this paper we use a field-structured chemiresistor to demonstrate that its response kinetics can be used to discriminate between analytes, even between those that have identical chemical affinities for the polymer phase of the sensor. The response kinetics is shown to be independent of the analyte concentration, and thus the magnitude of the sensor response, but is found to vary inversely with the analyte's saturation vapor pressure. Saturation vapor pressures often vary greatly from analyte to analyte, so analysis of the response kinetics offers a powerful method for obtaining analyte discrimination from a single sensor.
Chemiresistor
Saturation (graph theory)
Cite
Citations (7)
In this work, the application of molecularly imprinted polymer (MIP) as the recognition element of a chemiresistor sensor was introduced. Toluene-imprinted polymer and non-imprinted polymer (NIP) were synthesized and then mixed with carbon black powder in the presence of melted n-eicosane as the binder agent. The obtained composites were applied for the construction of chemiresistor sensors. The sensor, fabricated with toluene-imprinted polymer, showed a significant response towards toluene. Moreover, the response of the NIP-based (polymer synthesized without solvent) chemiresistor sensor was very small and negligible. The components of the MIP-based sensing composite were found to strongly influence the sensor sensitivity. Response surface experimental design methodology was applied to optimize the important parameters of the proposed sensor. Cross-sensitivity of the MIP-based chemiresistor sensor for different vapours was investigated and a satisfactory result was found for toluene vapour recognition. It was shown that the sensor response to toluene concentration in air was linear in the concentration range of 3.8 to 46.4 ppm. The detection limit and relative standard deviation (for five separate determinations) of the designed sensor were calculated equal to 0.8 ppm and 5.6%, respectively.
Chemiresistor
Molecularly imprinted polymer
Vapours
NIP
Cite
Citations (20)