Automatic electrochemical micro-pH-stat for biomicrosystems

Analytical Chemistry
Katsuya MorimotoHiroaki Suzuki

Abstract

A microelectrochemical pH-stat with an automatic feedback function was fabricated. The operation of the device is based on the nonstandard use of an electrochemical three-electrode system with a pH-sensitive reference electrode, a Ag/AgCl working electrode, and an iridium auxiliary electrode that functions as an actuator to adjust the solution pH. The combination of the electrodes caused a negative feedback in response to a pH change. The shift of the potential of the pH-sensitive reference electrode caused an overpotential on the Ag/AgCl working electrode, which then caused a significant current increase. This led to the electrolysis of water on the auxiliary electrode and the rapid recovery of the pH. The negative feedback function to stabilize the initial state could be confirmed for changes to both the acidic and basic directions. The performance of the pH-stat was characterized in the titration of acetic acid or ammonia. The charge generated in the feedback process changed linearly with respect to the concentration. The pH-stat was also used in the determination of urea by urease and that of the activities of trypsin and pepsin while maintaining the optimum pH for the enzymes. The pH to be fixed could be changed by changin...Continue Reading

References

Dec 24, 2005·Lab on a Chip·Erik A JohannessenJon M Cooper
Jan 11, 2007·Langmuir : the ACS Journal of Surfaces and Colloids·Sarah KösterJoyce Y Wong

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Citations

Jan 26, 2010·Journal of the American Chemical Society·Marco FrasconiItamar Willner
May 21, 2016·Lab on a Chip·N FominaH Ahmad
Apr 4, 2008·Electrophoresis·Fumihiro SassaHiroaki Suzuki
Mar 5, 2020·Lab on a Chip·Fumihiro SassaHiroaki Suzuki
Mar 12, 2010·Nano Letters·Yang YangDongsheng Liu
Jul 17, 2008·Analytical Chemistry·Fumihiro SassaHiroaki Suzuki
Nov 12, 2013·Analytical Chemistry·Daisuke ItohHiroaki Suzuki

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