Design and characterization of an amperometric glucose detector for flow injection analysis

An amperometric glucose detector, based on platinized membrane electrodes, for use in flow injection analysis has been designed and characterized. The platinized electrodes prepared for the sensor were constructed from a perfluorinated polymer matrix, Nafion 117, through an impregnation-reduction technique. This technique encompasses the incorporation of platinum (II) ions into the polymer, which are subsequently reduced to platinum (0). Once constructed, the platinized impregnated membrane (PIM) electrodes were characterized electrochemically, under both aqueous and non-aqueous conditions. The PIM electrodes were shown to preconcentrate ions of varying size and charge, as well as retain the complex ionic molecules necessary for mediation of glucose activity Cis-bis(2,2\u27-bipyridine-N,N\u27 dichloroosmium(III) chloride) dihydride, a redox mediator suitable for use with glucose oxidase, GO, was synthesized and evaluated along with an appropriate buffer system for the sensor. The buffer/electrolyte chosen was a pH 6.5; 20mM potassium phosphate/0. 1M sodium chloride solution. The reduction of the redox mediator was monitored effectively in the buffer solution with a PIM. Various techniques for incorporation of GO into the PIM electrode configuration are described, with preliminary results indicating the success of the PIM as an enzyme electrode. The PIM\u27s are used to measure current decay as a function of time to give an indication of glucose oxidase activity and detection limits for glucose concentrations are expected to be less than ImM. The PIM electrode system offers many unique advantages in the detection of glucose. Since glucose is monitored through a mediated response, the system is not limited by unbound oxygen. The polymer also discriminates against undesired anions, which decreases signals from interfering ions. Because of their rapid response, the PIM\u27s are an attractive detector for on-line flow analysis