Dr. Christopher Fenk: Digital Camera Colorimetry

Research

My current research focuses on the development of digital camera colorimetry (DCC) for use in educational settings and developing world applications, however I am also a trained organic chemist and have additional project plans related to the development of microwave assisted organic synthesis (MAOS) as well as general synthetic methods. In addition, data collected from my grant funded Improving Teacher Quality program, Conceptual Chemistry, (CC), is now available for review of the program over a period of eight years. This data suggests that significant gains in teacher content knowledge may be obtained as a result of “hands-on”, guided-inquiry based teacher education programs. This data is available for review and final analysis.

Using mobile phones as analytical instruments is particularly appealing due to the ubiquity of mobile devices worldwide. We are currently developing a number of digital camera colorimetry (DCC) protocols for use in introductory laboratory courses along with a number of relevant field applications. The red, green and blue detection channels of modern CMOS sensors provide for a range of data handling techniques based upon the sample of interest. Mathematical merging of data derived from these color channels also provides for gray channel analysis. A basis set of sample and data handling techniques has already been developed and is now being further extended into other analyses.

DCC was recently used to determine aspartame concentration in tabletop sweeteners in a manner analogous to that previously published. Quite remarkably, the results of this assay were on par with those obtained using a traditional spectrophotometer. More recently, DCC was used to determine the rate law for the classical crystal violet-sodium hydroxide (CV/NaOH) reaction. Results obtained using DCC were virtually identical to those obtained with a Beckman model DU-520 research grade instrument! Finally, we were able to use DCC to determine the equilibrium constant of the iron(III)-thiocyanate equilibrium. The equilibrium constant found using DCC is within 3% of the value obtained with a laboratory grade spectrometer, however further refinements are required to make the method more accurate. Both the CV/NaOH experiment and the [Fe(SCN)]²⁺ equilibrium constant experiments are classic undergraduate spectroscopy experiments that may be readily incorporated into the undergraduate curriculum.

Results from this research are to be published in the Journal of Chemical Education and involve adopting DCC into the general chemistry laboratory at KSU.

Selected Publications:

1. Christopher J. Fenk and Donald G. Gerbig, Jr. “Digital Camera Colorimetry: An Advanced Undergraduate Laboratory Experiment.” J. Chem. Educ. 2017 Manuscript in preparation.

2. Christopher J. Fenk, Donald G. Gerbig, Jr. and Joshua R. Menefee “Digital Camera Colorimetry: Basic Concepts and Introductory Experiments.” J. Chem. Educ. 2017 Manuscript in preparation.

3. Christopher J. Fenk, Douglas H. Motry, Nicole M. Hickman, Melissa A. Fincke, Barry Lavine “Identification and Quantitative Determination of Caffeine, Acetaminophen, and Acetylsalicylic Acid in Commercial Analgesic Tablets by LC-MS” J. Chem. Educ. 2010, 87(8), 838-841. DOI: 10.1021/ed100280y                                           Cited as one of the “top ten most read” JCE articles of 2011

4. Claudia Khourey-Bowers and Christopher J. Fenk "Influence of Constructivist Professional Development on Chemistry Content Knowledge and Scientific Model Development" J. Sci. Teacher Educ. [Online] 2009, DOI: 10.1007/s10972-009-9140‑0, [Print] J. Sci. Teacher Educ. 2009, (20) 437–457.

5. Christopher J. Fenk, Donald G. Gerbig, Jr. and Nathan Kaufman “A New Colorimetric Assay of Tabletop Sweeteners Using a Modified Biuret Reagent” J. Chem. Educ. 2007, 84 (10), 1676-1678.

6. Donald G. Gerbig, Jr., Christopher J. Fenk and Amy S. Goodhart “The Dot Blot ELISA: A Rapid and Simple Experiment to Demonstrate Antibody-Antigen Interactions” Am. Biol. Teach. 2000, 62(8), 583-587.

7. Christopher J. Fenk, Donald G. Gerbig, Jr. and Stephanie Y. Grooms “A Rapid and Highly Specific Western Blot Experiment for Introductory Biochemistry” J. Chem. Educ. 2000, 77 (3), 373-374.