Solution to the Problem of Interferences in Electrochemical Sensors Using the Fill-and-Flow Channel Biosensor

Abstract

A generic fill-and-flow channel biosensor with upstream electrodes to determine the extent of interferences in the sample is described. A pair of upstream electrodes poised at a suitable potential allows both the calculation of the extent of removal of interfering agents and the effect of interfering agents at the detector electrode. A model was developed and tested that predicts the concentrations of all species throughout the channel and, hence, the current at each electrode due to each species. This enables correction of the detector electrode current and a more accurate determination of the analyte concentration. The concept was applied to a biosensor for the determination of glucose in the presence of ascorbic acid, acetamidophenol, and uric acid, as well as glucose in wine samples containing polyphenolic interfering agents.

A Portable Fill‐and‐Flow Channel Biosensor with an Electrode to Predict the Effect of Interferences

“…First, a model is developed to investigate the effect of the location of upstream electrode on the response of detector electrode. It is similar to previous work [13] but the predictor electrode is located on the opposite side of the channel to the detector electrode (see Figure 1). The channel can be divided into five regions defined by 1: the predictor electrode (0 ± x 1 ), 2: the gap between the predictor electrode and the enzyme layer (x 1 ± x 2 ), 3: the enzyme layer (x 2 ± x 3 ), 4: the gap between the enzyme layer and the detector electrode (x 3 ± x 4 ) and 5: the detector electrode (x 4 ± x 5 ).…”

“…In this case a mathematical model is necessary to calculate the contribution of the current due to the redox active species at the detector electrode. Previous work has indicated the feasibility of this approach [13] but at the cost of some complexity. Here we try to find suitable conditions in which the reactions at the upstream electrode have no significant effect on the current at the downstream electrode.…”

“…Boundary conditions in the other four regions are the same as described in an earlier publication [13]. Results of this modeling are shown in Figure 3.…”

“…This strategy uses a filland-flow channel biosensor [9 ± 13] with a pair of predictor electrodes introduced upstream of the enzyme layer and the detector electrode [13]. When the sample flowed through the channel and arrived at the predictor electrodes, the interfering species in the sample were oxidized and a corresponding oxidation current measured.…”

Dependence of the response of an amperometric biosensor formed in a micro flow channel on structural and conditional parameters

“…Suzuki and Akaguma (2000) examined the influence of chemical cross-talk between two amperometric biosensors formed in a micro flow channel. Zhao et al (2003) examined the elimination efficiency of interferents using electrodes placed in the upper stream of a glucose sensor. Both qualitative and quantitative changes in behavior when the structural and conditional parameters are changed are necessary information for designing novel micro systems.…”