title: Calibrant-Free Analyte Quantitation via a Variable Velocity Flow Cell.
abstract: In this paper, we describe a novel method for analyte quantitation that does not rely on calibrants, internal standards, or calibration curves but, rather, leverages the relationship between disparate and predictable surface-directed analyte flux to an array of sensing addresses and a measured resultant signal. To reduce this concept to practice, we fabricated two flow cells such that the mean linear fluid velocity, U, was varied systematically over an array of electrodes positioned along the flow axis. This resulted in a predictable variation of the address-directed flux of a redox analyte, ferrocenedimethanol (FDM). The resultant limiting currents measured at a series of these electrodes, and accurately described by a convective-diffusive transport model, provided a means to calculate an "unknown" concentration without the use of calibrants, internal standards, or a calibration curve. Furthermore, the experiment and concentration calculation only takes minutes to perform. Deviation in calculated FDM concentrations from true values was minimized to less than 0.5% when empirically derived values of U were employed.
authors.affiliation: Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States.|Nano Institute of Utah, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Jason G
authors.initials: JG
authors.lastname: Beck
authors.affiliation: Department of Chemical Engineering, University of Utah , Salt Lake City, Utah 84112, United States.|Nano Institute of Utah, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Aleksander
authors.initials: A
authors.lastname: Skuratovsky
authors.affiliation: Department of Chemical Engineering, University of Utah , Salt Lake City, Utah 84112, United States.|Nano Institute of Utah, University of Utah , Salt Lake City, Utah 84112, United States.|Department of Surgery, School of Medicine, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Michael C
authors.identifier: 0000-0002-2385-6413
authors.initials: MC
authors.lastname: Granger
authors.affiliation: Department of Chemistry, University of Utah , Salt Lake City, Utah 84112, United States.|Department of Chemical Engineering, University of Utah , Salt Lake City, Utah 84112, United States.|Departments of Bioengineering and Pathology, University of Utah , Salt Lake City, Utah 84112, United States.|Nano Institute of Utah, University of Utah , Salt Lake City, Utah 84112, United States.
authors.forename: Marc D
authors.initials: MD
authors.lastname: Porter
mesh_terms: D000465:Algorithms; D002138:Calibration; D004058:Diffusion; D004560:Electricity; D055664:Electrochemical Techniques / Q000295:instrumentation*; D004566:Electrodes; D004867:Equipment Design; D005296:Ferrous Compounds / Q000032:analysis*
chemical_list: D005296:Ferrous Compounds; C071550:ferrocenemethanol