Quantitative Detection of Complex Mixtures using a Single Chemical Sensor: Analysis of Response Transients using...

Area of Science:

• Analytical Chemistry
• Chemical Sensing
• Signal Processing

Background:

• Chemical sensors often lack specificity, complicating the analysis of complex mixtures.
• Sensor arrays are a common solution but can be costly and complex.
• Accurate identification and quantification of multiple analytes remain a challenge in chemical sensing.

Purpose of the Study:

• To present and validate a novel signal processing technique for analyzing multi-analyte mixtures using a single sensor.
• To demonstrate a method that accurately identifies and quantifies analytes without prior concentration assumptions.
• To provide a cost-effective and simpler alternative to sensor arrays for chemical mixture analysis.

Main Methods:

• Utilized a signal-processing technique based on estimation theory, specifically multiple stages of exponentially weighted recursive least-squares estimation (EW-RLSE).
• Developed a sensor response model incorporating parameters for each coating-analyte pair.
• Tested the technique on polymer-coated shear-horizontal surface acoustic wave (SH-SAW) devices analyzing mixtures of volatile organic compounds (VOCs) in water.

Main Results:

• The EW-RLSE technique successfully identified and quantified analytes in multi-analyte mixtures using data from a single sensor.
• The method accurately determined the presence of analytes by first eliminating absent compounds from the model.
• Quantification of constituent analytes was achieved with high accuracy in the final EW-RLSE stage.

Conclusions:

• A single polymer-coated sensor combined with the EW-RLSE technique can effectively analyze complex chemical mixtures.
• This approach offers a significant advantage over sensor arrays, reducing cost and complexity.
• The method requires minimal training, relying only on the characterization of individual analytes and interferents.