Gated Amperometric Pulse Sequences for Analyte Measurement
Solution Overview
Problem
Conventional electrochemical sensor systems face inaccuracies in determining analyte concentrations due to the hematocrit effect, mediator background, and other factors, leading to time-consuming measurements and reduced precision.
Innovation Solution
A gated amperometric method involving a pulse sequence with at least 3 duty cycles within 180 seconds is applied to a sensor strip with a diffusion barrier layer, allowing for accurate analyte concentration determination even without reaching a steady-state condition, and includes features like under-fill detection and temperature correlation using decay constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional amperometric methods are used to measure analyte concentration, then the measurement can be performed continuously, but the current changes rapidly with time and steady-state is not reached, leading to measurement inaccuracy
Solution Approach 1:
The patent applies periodic pulsed amperometric measurements instead of continuous measurement. The method performs multiple discrete measurements at specific time points (e.g., 0.5s, 1.0s, 1.5s, 2.0s, 2.5s, 3.0s) after sample application, allowing the system to capture current values during the transient phase without requiring steady-state conditions. This periodic sampling approach resolves the contradiction by obtaining accurate measurements during the time when conventional methods would be inaccurate.
Solution Approach 2:
The patent performs preliminary calibration measurements using standard solutions with known analyte concentrations before measuring unknown samples. The calibration establishes a relationship between current values and concentrations that accounts for the transient behavior of the system. This preliminary action allows accurate quantification without waiting for steady-state conditions during actual measurements.
2Measurement precision
If the measurement system waits for steady-state condition to ensure accuracy, then measurement precision improves, but the analysis time increases significantly
Solution Approach 1:
The system performs periodic measurements at multiple discrete time points rather than waiting for steady-state. By sampling current values at 0.5s intervals up to 3.0s and using the last measured value (at steady-state or near steady-state), the method achieves both speed and accuracy. The periodic approach captures the evolution of current over time and selects the appropriate value for quantification.
Solution Approach 2:
The measurement protocol is dynamically adjusted based on the observed current behavior. The system performs measurements at fixed intervals and automatically selects the last measured current value for quantification, adapting to whether steady-state is reached within the measurement window. This dynamic approach optimizes the balance between measurement time and accuracy for each individual measurement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces bias from mediator background and hematocrit effects, enhances measurement precision, and shortens analysis time by using transient current data and multiple calibration constants, while also detecting under-fill and temperature variations.
Implementation Method 1
the analyte undergoes a redox reaction with an enzyme or similar species to generate an electric current that may be measured and correlated with the concentration of the analyte
Implementation Method 2
A sensor strip including a diffusion barrier layer (DBL) on a working electrode
Data Source
AI summary
A sensor system, device, and methods for determining the concentration of an analyte in a sample is described. Gated amperometric pulse sequences including multiple duty cycles of sequential excitations and relaxations may provide a shorter analysis time and/or improve the accuracy and/or precision of the analysis. The disclosed gated amperometric pulse sequences may reduce analysis errors arising from the hematocrit effect, variance in cap-gap volumes, non-steady-state conditions, mediator background, under-fill, temperature changes in the sample, and a single set of calibration constants.