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Ingrid Fritsch Professor Emphasis: analytical CHEM 250 Phone: 479-575-6499 FAX: 479-575-4049 ifritsch@uark.edu

Degrees:

• Postdoctoral Associate Massachusetts Institute of Technology, 1990-1992
• Ph.D. University of Illinois at Urbana Champaign, 1990
• B.S. University of Utah, 1985

Teaching Areas:

Chemical Education Activities and Resources

Research Interests:

micro electro-analytical devices

Research:

Analytical and Bioanalytical Chemistry The unifying theme of our research program is the development of multifunctional, miniaturized analytical devices with integrated components on a single substrate. Such “labs-on-a-chip” have promise in revolutionizing sample preparation, chemical analysis, and chemical synthesis. A wide variety of applications are possible, including on-site analysis of environmental samples, analysis of key components in body fluids at the doctor’s office or at home, and synthesis and purification of materials on a small scale. To carry out this work, our activities are interdisciplinary in nature, often requiring scientific collaborations with other chemists, chemical engineers, electrical engineers, food scientists, and industrial partners. More specifically, we investigate chemistry in the limit of ultrasmall volumes (nanoliters to picoliters), near materials having ultrasmall features (submicron patterning), and with new approaches to moving solutions around to carry out sequential reactions in an automated way (microfluidics). In addition, we study the means of interfacing inorganic electrodes and micro/nanostructures with assemblies of organic and biologically- important molecules. Computer simulations are used as a complementary tool to further investigate these systems. Analytical instrumentation that is essential to this work includes electrochemistry, polarization-modulation Fourier transform infrared spectroscopy (PM-FTIR), surface probe microscopy (e.g. atomic force microscopy), X- ray photoelectron spectroscopy, and mass spectrometry. Several projects also involve hands-on experience with microlithographic techniques. Ultrasmall Electrochemical Devices. Essentially, smaller (both in size of device and of sample) is better, more sensitive, and provides better detection limits! A variety of procedures that were developed for silicon wafer-based, integrated circuit electronics fabrication are used to construct microscopic devices with submicron dimensions. We have also developed a simple and inexpensive fabrication method for devices on flexible substrates that are capable of self-contained electrochemistry from microliter to picoliter-sized samples. For example, cavities of various geometries can be formed into layered materials of conductor and insulator, each 100’s of angstroms to several 100’s of microns thick. This yields nanometer to micron-sized features on the walls of the cavities. Such devices provide multiple functionality both laterally (parallel to the plane of the substrate) and vertically (perpendicular to the plane of the substrate). If several of the layers are conducting, then many electrodes may reside in a very small space. The combination of the close proximity of these electrodes and the ability to analyze ultrasmall samples in the small space provides unique capabilities that are not possible with traditional electrochemical cells. We are using this basic construct to develop fast microelectrochemical immunoassays (on volumes less than 1µL) and to investigate new approaches for in vivo analysis of neurotransmitters. A New Approach to Microfluidics. We have developed a new method for stirring on a picoliter scale, moving solutions from one site to another on a chip for processing, and forcing solvent through channels to carry out separations of mixtures. It involves applying a phenomenon, magnetohydrodynamics (MHD), that is better known in the astrophysics of plasmas and liquid metal pumping than it is in analytical chemistry. MHD involves three physical fields that are at right angles to each other: electric, magnetic, and flow. Application of an electric and magnetic field in small channels or microscopic reactor or sensor vessels containing aqueous or non-aqueous solution results in controlled flow or stirring. We are investigating the fundamental properties of MHD and how MHD may be used in a wide variety of analytical chemistry applications to enhance sensitivity, detection limits, provide fast reactions, and carry out complete sample manipulation, separation, and detection on an ultrasmall volume scale. Patterning Organic Materials using Applied Potentials. Potential-dependent modification provides a means to specifically modify different submicron- and micron-sized electrodes in various geometries and locations with organic molecules so that arrays of chemical sensors may be constructed. An emphasis of this work is understanding the influence of electrochemical environment and reactions of the organic molecules with the surfaces of the electrodes under potential control. Some research in this area focuses on gold surfaces modified with self-assembled monolayers (SAMS) of organothiols. We have ongoing projects on the stability of SAMs as a function of potential, time, conditions, environment, and solvents. The products formed are being characterized, as are the surface and solution mechanisms that are responsible for any instability. Interfacing Organic Materials to Inorganic Micro and Nanostructures We are incorporating the natural selectivity of biologically-important molecules into thin films to discriminate electrochemical signals for micro and nanoscopic sensors. This involves the design and construction of a well-defined biomembrane-like layer not only on electrode surfaces, but also across microfabricated cavities, essentially encapsulating self-contained electrochemical devices inside. New sensing materials are being synthesized from thin organic films of mixed hydrophobic and hydrophilic properties that are formed by SAMs and phospholipids. These materials form the basis of biomimetic membranes and artificial biological cells.

Publications/Presentations:

Selected Papers

Gong, W.; Elitzin, V. I.; Janardhanam, S.; Wilkins, C. L.; Fritsch, I., "Effect of Laser Fluence on Laser Desorption Mass Spectra of Organothiol Self-Assembled Monolayers on Gold", J. Am. Chem. Soc., 2001, 123, 769-770.   Neugebauer, S.; Evans, S. R.; Aguilar, Z. P.; Fritsch, I.; Schuhmann, W. 3Analysis in Ultrasmall Volumes: Microdispensing of Picoliter Droplets and Rapid Analysis without Protection from Evaporation2, Anal. Chem. 2004, 76(2), 458-463.

Evans, S. R.; Fritsch, I. 3A Self-Contained Microelectrochemical Cavity System Comprising of a Polymer and Phospholipid Membrane Suspended Over a Picoliter Volume2, Electroanalysis , 2004, 16, 45-53.

Arumugam, P. U.; Bell, A. J.; Fritsch, I. 3Inducing Convection in Solutions on a Small Scale: Electrochemistry at Microelectrodes Embedded in Permanent Magnets 2, IEEE Transactions on Magnetics, 2004, 40(4), 3063-3065.

Clark, E. A.; Fritsch, I. 3Anodic Stripping Voltammetry Enhancement by Redox Magnetohydrodynamics2, Anal. Chem., 2004, 76(8), 2415-2418.

Arumugam, P. U.; Clark, E. A.; Fritsch, I. 3Use of Paired, Bonded NdFeB Magnets in Redox Magnetohydrodynamics2, Anal. Chem. 2005, 77, 1167-1171.

Clark, E.A.; Fritsch, I.; Nasrazadani, S.; Henry, C.S. "Analytical Techniques for Materials Characterization", as Chapter 18 in Advanced Electronic Packaging, 2nd edition, R. K. Ulrich and W. D. Brown (Eds.), IEEE Press, Piscataway, NJ, 2006, pp. 725-791.

Anderson, E. C.; Fritsch, I. 3Factors Influencing Redox Magnetohydrodynamic-Induced Convection for Enhancement of Stripping Analysis2, Anal. Chem. 2006, 78(11), 3745-3751.

Aguilar, Z. P.;Arumugam, P.; Fritsch, I. 3Study of magnetohydrodynamic driven flow through LTCC channel with self-contained electrodes2, J. Electroanal. Chem. 2006, 591, 201-209.

Etienne, M.; Anderson, E. C.; Evans, S. R.; Schuhmann, W.; Fritsch, I. 3Feedback-Independent Pt Nanoelectrodes for Shearforce-Based Constant-Distance Mode Scanning Electrochemical Microscopy2, Anal. Chem. 2006, 78(20), 7317-7324.

Arumugam, P. U.; Fakunle, E. S.; Anderson, E. C.; Evans, S. R.; King, K. G.; Aguilar, Z. P.; Carter, C. S.; Fritsch, I. 3Redox Magnetohydrodynamics in a Microfluidic Channel: Characterization and Pumping2, J. Electrochem. Soc. 2006, E185-E194.

Eyitayo S. Fakunle, Zoraida P. Aguilar, John L. Shultz, Alan D. Toland, and Ingrid Fritsch, 3Evaluation of Screen-Printed Gold on Low-Temperature Co-Fired Ceramic as a Substrate for the Immobilization of Electrochemical Immunoassays2 Langmuir, 2006, 10844-10853.

Weston, M. C.;Anderson, E. C.; Arumugam, P. U.; Yoga Narasimhan, P.; Fritsch, I. 3Redox Magnetohydrodynamic Enhancement of Stripping Voltammetry: Toward Portable Analysis Using Disposable Electrodes, Permanent Magnets, and Small Volumes2Analyst 2006, 131, 1322-1331.

Fritsch, I.; Aguilar, Z. P. 3Advantages of Downsizing Electrochemical Detection for DNA Assays2, Anal. Bioanal. Chem. (Trends Article), 2006, 159-163.

Etienne, M.; Dierkes, P.; Erichsen, T.; Schuhmann, W.; Fritsch, I. 3Constant-Distance Mode Scanning Potentiometry. High Resolution pH Measurements in Three-Dimensions2, Electroanalysis 2007, 19, 318-323.