title: Versatile common instrumentation for optical detection of pH and dissolved oxygen.
abstract: The recent trend toward use of disposable and miniature bioreactors requires the use of appropriate sensors. pH and dissolved oxygen (DO) are often measured using optical chemical sensors due to their small form factor and convenience in use. These sensors are often interrogated using a specialized opto-electronic transducer that is designed around the optical sensor. In this contribution, we are presenting a new class of opto-electronic transducers that are usable with several different chemical sensors without the need to switch the optics or hardware when changing the type of the chemical sensor. This allows flexibility closer to the lab-grade devices while the size is closer to a dedicated sensor. This versatile instrumentation is capable of seamlessly switching between the pH and DO measurement modes and is capable of auto recognition of the sensor type. The principle of ratiometric fluorescence is used for pH measurements, and that of fluorescence lifetime for DO measurements. An approach to obtain identical calibrations between several devices is also presented. The described hardware constitutes common instrumentation for measuring either pH or DO and has been tested in actual bioprocesses. It has been found adequate for continuous bioprocess monitoring.
authors.affiliation: Department of Computer Science and Electrical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA.
authors.forename: Neha
authors.initials: N
authors.lastname: Sardesai
authors.affiliation: Center for Advanced Sensor Technology and Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA.
authors.forename: Govind
authors.initials: G
authors.lastname: Rao
authors.affiliation: Department of Computer Science and Electrical Engineering, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, Maryland 21250, USA.
authors.forename: Yordan
authors.initials: Y
authors.lastname: Kostov
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002138:Calibration; D004867:Equipment Design; D004926:Escherichia coli / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D008962:Models, Theoretical; D055096:Optical Devices; D010100:Oxygen / Q000737:chemistry*; D012984:Software
chemical_list: D010100:Oxygen