Controlled slew rate transition for electrochemical analysis

摘要

Measurement systems and methods are disclosed for minimizing the effects created by a meter's output amplifier during electrochemical measurements. In the systems and methods, transition of an excitation potential applied between electrodes of a test strip is controlled so that it is at a sufficiently slow rate below a slew rate capability of the system (but still fast enough to minimally impact overall test time) to reduce variability in the test results. The methods and systems therefore use a transition having a ramp-shaped waveform, a sinusoidal-shaped waveform or an exponential-shaped waveform. Additionally, the excitation potential can be purposefully controlled by a processor, memory driven digital-to-analog converter or external circuitry at a rate sufficiently slow to make variations in the analog electronics slew rate insignificant for all sample types and test conditions.

主权项

1. A method of electrochemical analysis, the method comprising the steps of:
providing an electrochemical test strip with a mediator system and electrodes; introducing a body fluid sample to the mediator system and in contact with electrodes of the test strip; applying an excitation potential difference between the electrodes of the test strip and across the body fluid sample, wherein the excitation potential difference has a transition time of at least 100 μsec, wherein the applying the excitation potential difference step is performed by a meter having a slew rate capability, wherein the slew rate at which the meter applies the excitation potential difference is slower than the slew rate capability of the meter, and wherein the excitation potential difference is at least 300 mV and the slew rate is at most about 900 V/sec; and determining analyte concentration in the body fluid sample based on an electrical response to said excitation potential difference.