Simple and Sensitive Paper-Based Device Coupling Electrochemical Sample Pretreatment and Colorimetric Detection.

Area of Science:

• Analytical Chemistry
• Forensic Science
• Materials Science

Background:

• Cocaine adulteration with procaine is a significant forensic challenge.
• Existing analytical methods for detecting procaine in cocaine samples can be complex and costly.
• There is a need for rapid, portable, and selective detection methods for forensic analysis.

Purpose of the Study:

• To develop a simple, portable, low-cost, and high-throughput visual colorimetric paper-based analytical device (PAD) for procaine detection.
• To assess and mitigate interference from common cutting agents in seized cocaine samples.
• To validate the accuracy and reliability of the developed PAD using real-world forensic samples.

Main Methods:

• Development of a visual colorimetric paper-based analytical device (PAD).
• Investigation of interference from common cutting agents found in cocaine.
• Implementation of a novel electrochemical approach for sample pretreatment to enhance selectivity.
• Optimization of experimental conditions for procaine detection.
• Validation using seized cocaine samples and an addition and recovery protocol.

Main Results:

• A linear analytical curve for procaine was obtained within the concentration range of 5 to 60 μmol L⁻¹.
• A low detection limit of 0.9 μmol L⁻¹ for procaine was achieved.
• The developed PAD demonstrated high selectivity, effectively minimizing interference from common cutting agents.
• The accuracy of the method was confirmed through analysis of seized cocaine samples.

Conclusions:

• The developed paper-based analytical device offers a simple, portable, and cost-effective solution for the detection of procaine in seized cocaine.
• The integration of an electrochemical pretreatment step significantly improves the selectivity of the method.
• This technology has the potential to be a valuable tool in forensic laboratories for rapid drug analysis.