Determination of partial fill in electrochemical strips
AssigneeAgaMatrix, Inc.
InventorsIan Harding, Steven Diamond, Richard Williams, Sridhar G. Iyengar
Life of this patent
Estimating the term…
Abstract
Partial fill of an electrochemical test strip is determined by making a DC determination of double layer capacitance from charging or discharging charge on a test strip containing sample, for example a blood sample to be tested for glucose. The measured double layer capacitance is compared to a reference value. The double layer capacitance may be determined as an integral or differential capacitance. Double layer capacitance may also be used for quality control to monitor the quality of electrode formation, particularly in strips using screen printed electrodes.
Claims17
A method for detection of partial fill in an electrochemical test strip having electrodes and a liquid sample disposed between the electrodes comprising the steps of:
- (a) introducing sample to an electrochemical test strip;
- (b) applying a potential difference, Vapp, between the electrodes of the test strip;
- (c) switching off the applied potential at time tswitch and optionally reapplying a second potential;
- (d) observing current generated and determining from the observed current a double layer charging or discharging at the electrodes;
- (e) observing a voltage change after the applied potential is switched off, and determining the double layer capacitance of test strip from the measured double layer charging or discharging and the observed voltage change;
- and
- (f) comparing the determined double layer capacitance to a reference value, wherein a double layer capacitance less than the reference value is an indication that the liquid sample covers a portion of the electrodes and that the electrochemical test strip is only partially filled.
Dependencies are inferred from the claim text.