This paper examines the use of paper-based sensors for in-field detection of chlorate-based explosives and quantification of oxyanions.
The authors of this study developed a paper-based sensor for the in-field detection of chlorate-based explosives. The authors demonstrated the analytical performance of the sensor and evaluated the selectivity of the sensor by testing other oxidizers that did not present any electrochemical activity with the molybdate sensing layer. The authors also performed an interferent study with sugar, commonly used as fuel in improvised explosive devices (IEDs), and other common white household powders such as baking soda, flour, and corn starch and neither a false positive nor a false negative result was observed. As bromate has been reported to have a stronger catalytic effect than chlorate on the redox activity of molybdate, the quantification of bromate was also explored, and a bromate sensor was developed using the findings of the chlorate sensor. IEDs are a global threat due to their destructive potential, the easy access to raw materials, and online instructions to manufacture them. The standard methods to detect chlorate are mainly designed for laboratory-only testing. Thus, field instrumentation capable of detecting oxidizers from explosives fuel-oxidizers is critical for crime scene investigation and counterterrorism efforts. The sensor has an electrodeposited molybdate sensing layer, as chlorate was reported to have a catalytic effect on the molybdate reduction. The chlorate detection relies on monitoring the change in redox activity of the molybdate sensing layer using different electroanalytical techniques.