The development of chemical sensors is our area of general interest. This research usually involves the application of new developments in electronics and transducer design to particular problems in analytical chemistry. Previous interests have been the development of enzyme electrodes ("Rapid Detection of Salmonella Typhimurium Using Immunoelectrochemical Biosensor Coupled with Immunomagnetic Separation," Y-H. Che, Z.,Yang, Y. Li, D.W. Paul, M. Salvik, Journal of Rapid Microbial Methods, 7, 47-59 (1999)), the application of acoustic wave devices to bioanaytical analysis ("An acoustic wave biosensor for human low-density lipoproteins particles: Construction of selective coatings," S. Snellings, J. Fuller, M. Pitner, D.W. Paul, Biosensors and Bioelectronics, 19, 353-363, 2003; (see"An Electronic Oscillator with Automatic Gain Control: EQCM Applications", C.Chagnard, A.N. Watkins, T. Beeler, D.W. Paul, Sensors and Actuators B, 32, 129-136,1996)), and gas sensing with porphryin films.
Previously, emphasis has been placed on the development of sensors based on new physical phenomena. This has resulted in the development of new classes of sensors that have proliferated into many applications. Our current research seeks to investigate some of the "overlooked" aspects of chemical sensing. One of these is calibration, or the relationship between sensor-response and concentration. Sensors used for continuous monitoring are often fouled by a myriad of components in the medium. For most sensors, this causes the sensor to become out of calibration. Re-calibration can be achieved by either placing the sensor in a "standard" and recording the reading, or determining the sensitivity of the sensing layer and manufacturing all of the sensors in the same way and throwing the used ones away. Our approach has been to re-calibrate the sensor without removal or disposal by generation of a small amount of standard a short distance away from the sensor. The standard then diffuses through to the sensor and a new response is recorded. We have found it possible to recalibrate oxygen sensors in this way (see"In Situ Calibrated Oxygen Electrode," Clifton D. Johnson, David W. Paul, Sensors and Actuators B: 105 (2005), 322-328). We also have efforts to improve/study reduction of oxygen at different types of electrodes. Finding ways to speed oxygen reduction would provide improvements to oxygen sensors as well as fuel cells.
Ph.D., University of Cincinnati
IR-100 Award, 1985