Sensors conductive polymers

A chemical sensor array (consisting of eight conducting polymer sensors) derived from an electronic nose [62], for the characterization of headspace gas from a sparged liquid sample... 

Carvalho, E. R., Consolin Filho, N., Venancio, E. C., Osvaldo, N. O., Jr., Mattoso, L. H. C., and Martin-Neto, L. (2007). Detection of brominated by-products using a sensor array based on nanostructured thin films of conducting polymers. Sensors 7, 3258-3271. 

PNA strand, resulting in an increase of the electrochemical signal (SWV peak current) as a result of probe-target hybridization. The PNA-functionalized conductive polymer sensor allowed for a detection limit of approximately 10 nM, and the feasibility for single-nucleotide mismatch detection was also demonstrated. 

Electrical, resistive Mattoso (Brasil) Conducting polymer sensors [18]... 

Conducting polymer sensors can be operated either to quantitatively measure the concentration of a target vapor species or to qualitatively analyze a complex mixture of vapors. For single vapors, the detection limits can be in the low-ppm region. Exposure to a mixture of vapors results in a unique pattern of responses, which is usually deciphered using standard chemometric techniques. The pattern can be used like a fingerprint to identify certain products, or to establish the quality of foodstuffs, wines, perfumes, etc. The electronic nose has similar components as the natural nose this is illustrated in Figure 1.15. 

FIGURE 1.14 The electronic nose, (a) Response of conducting polymer sensor to different concentrations of toluene (Tol) and ethanol (EtOH). (b) Photograph of portable electronic nose with an array of conducting polymer sensors (bottom left). 

M. Josowitz, J. Janata, K. Ashley and S. Pons, Electrochemical and ultraviolet-visible spectroelectrochemical investigation of selectivity of potentiometric gas sensors based on polypyrrole, Anal. Chem., 1987, 59, 253 T. Sata. Possibility for potentiometric humidity sensor of composite membranes prepared from anion-exchange membrane and conducting polymer, Sensor Actuators, B, 1995, 23, 63 K. Ogura, H. Shiigi, T. Oho and T. Tonosaki, A C02 sensor with polymer composites at ordinary temperature, J. Electrochem. Soc., 2000,147, 4351. 

Towards an integrated electronic nose using conducting polymer sensors , Hatfield, J. V., Neaves, P., Hicks, P. J., Persaud, K., and Travers, P., Sensors and Actuators B, 1994, 18-19, 221 Electronic nose detects the nast nifis, Coghlan, A., New Scientist, 1994, 141 (1911), 20 Electronic noses principles and applications , Gardner, J. W. and Bartlett, P. N., OUP, Oxford, 1999. 

Electrochemical, such as ion-selective electrodes (ISE), ion-selective field affects transistors (ISEET), solid electrolyte gas sensors, semiconductor-based gas sensors, and conducting polymer sensors. Most electrochemical sensors are based on potentiometry, voltammetry, or amperometry although coulometry and conductimetry have also been utilized. 

Electronic noses have also been used to analyze meat flavor. Warmed-over flavor (WOE) in beef was studied by 32 conducting polymer sensors [30]. The meat was processed by vacuum cook-in-bag/tray technology (VCT) and stored in a refrigerator. The VCT process involves treatment at 50°C for 390 minutes. The authors indicated that electronic noses can be readily utilized for WOE identification in beef and can be a useful addition to sensory analysis. 

Canhato and Magan [39] have also described the detection of microbial and chemical contamination of potable water. Two electronic noses consisting of conducting polymer sensor arrays were compared for the early detection and discrimination of bacterial species, fungal spores, and trace concentrations of pesticides. Using PCA and CA allowed differentiation of the bacterial and fungal species after 24 hours of incubation at 25°C. However, this was not possible with the pesticides. 

To improve classification ability, the effect of environmental parameters in different data preprocessing algorithms was evaluated. The algorithm that allowed the least humidity, temperature, and day correlation was selected. PCA was used to determine discriminating ability. The results indicate that MOS sensors were much better at discriminating the different odors when compared with the conducting polymer sensors. It was also shown that the location of samples for MOS sensors depended on the quality of water. 

Stella, R., Barisci, J.N., Serra, G., Wallace, G.G., and De Rossi, D. Characterisation of olive oil by an electronic nose based on conducting polymer sensors. Sensors and Actuators B Chemical, 63,1-9. 2000. 

Panigrahi and co-workers [39], analyzed the headspace from fresh beef strip loins kept at 4 "C for 10 days by a commercially available Cyranose-320 with conducting polymer sensors. They developed various classification models using radial basis... 

Barisci, J.N., G.G. Wallace, M.K. Andrews, A.C. Partridge, and P.D. Harris. 2002. Conducting polymer sensors for monitoring aromatic hydrocarbons using an electronic nose. Sens Actuators B Chem 84 252. 

Guadarrama, A., J.A. Fernandez, M. Iniguez, J. Souto, and J.A. de Saja. 2001. Discrimination of wine aroma using an array of conducting polymer sensors in conjunction with solid-phase microextraction (SPME) technique. Sens Actuators B Chem 77 (1-2) 401. 

Partridge, A.G., P. Harris, and M.K. Andrews. 1996. High sensitivity conducting polymer sensors. Analyst 121 1349-1353. 

Figure 2 Detection of an unknown discharge in the wastewater influent with the conducting polymer sensor array. (Reproduced with permission from Bourgeois W, Gardey G, Servieres M, and Sluetz RM (2003) A chemical sensor array based system. Sensors and Actuators B 91 109-116 Elsevier.)...

Barisci, J. N. Wallace, G. G. Andrews, M. K. Partridge, A. C. Harris, P. D. Conducting polymer sensors for monitoring aromatic hydrocarbons nsing an electronic nose. Sens. 

Apostolidis A (2004) Combinatorial approach for development of optical gas sensors concept and application of high-throughput experimentation. PhD thesis, University of Regensburg, Regensburg Bai H, Shi G (2007) Gas sensors based on conducting polymers. Sensors 7 267-307... 

Conducting polymer sensors Ambient temperature operation, sensitive to many VOCs, short response time, diverse sensor coatings, inexpensive, resistance to sensor poisoning Sensitive to humidity and temperature, sensors can be overloaded by certain analytes, sensor life is limited... 

---