This past year, on March 11, 2019, Professor Dennis C. Johnson of Iowa State University passed away. His passing deeply saddens the Pine Research team as Dennis played an integral part in our early efforts to develop electrochemical instrumentation. In the mid-1960s, Dennis was a graduate student and part of Professor Stanley Brukenstein’s team of electrochemists at the University of Minnesota who were doing novel research on the theory and application of rotating ring-disk electrodes (RRDEs). The Minnesota team (which also included fellow graduate student Duane Napp and visiting scientist John Albery from Oxford University) was building upon earlier RRDE research performed in Russia, and the team’s efforts helped launch the RRDE as one of the primary tools for modern electroanalytical research.
In subsequent years, Dennis and Duane collaborated with the owner of Pine Instrument Company, Ted Hines, to construct several early RRDE instruments. Dennis and Duane also worked with Ted in the design and commercialization of a special bipotentiostat circuit which allowed independent control of the disk and ring potentials. After Dennis became a professor at Iowa State University, he and his graduate students remained directly involved in the commercial production of rotating electrodes, playing a key role in the area of quality control. As demand for rotating electrodes increased, it remained important that each individual rotating electrode be inspected and tested by a qualified electrochemist. Dennis and his students at Iowa State did much of this early testing, and to this very day, rotating electrodes from Pine Research are tested according to his methods in some cases, these tests are still performed by scientists who were originally trained in his laboratory.
Dennis Johnson’s contributions to Pine cannot be overstated, and Pine remains close with the Johnson family and with several Johnson group alumni. Dennis will be sorely missed, not just by his family and the students whose lives he touched, but also by the entire team here at Pine. We would not be where we are today without all of the help we received from Dennis over the many years.
Below you can find a link to an official obituary as well as to an Iowa State University biography of Dennis Johnson highlighting his academic career.
A history of the development of the Rotating Ring-Disk Electrode and the role played by Dennis Johnson can be found in the following Interface magazine article published by the Electrochemical Society (ECS):
Finally, Dennis left us with a timeless and wonderful piece of written encouragement and advice which can be found on the Society for Electroanalytical Chemistry (SEAC) website at the link below: