Trace Detection of Pentaerythritol Tetranitrate Using Electrochemical Gas Sensors

Praveen K Sekhar,Jie Zhou,Eric R Hamblin,Hui Wang

doi:10.1155/2014/234607

Praveen K Sekhar, Jie Zhou + Show 2 more

Open Access

https://doi.org/10.1155/2014/234607

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Abstract

Selective and sensitive detection of trace amounts of pentaerythritol tetranitrate (PETN) is demonstrated. The screening system is based on a sampling/concentrator front end and electrochemical potentiometric gas sensor as the detector. A single sensor is operated in the dominant hydrocarbon (HC) and nitrogen oxides (NOx) mode by varying the sensor operating condition. The potentiometric sensor with integrated heaters was used to capture the signature of PETN. Quantitative measurements based on hydrocarbon and nitrogen oxide sensor responses indicated that the detector sensitivity scaled proportionally with the mass of the explosives (10 μg down to 200 ng). The ratio of the HC integrated peak area to the NOxintegrated peak area is identified as an indicator of selectivity. The HC/NOxratio is unique for PETN and has a range from 1.7 to 2.7. This detection technique has the potential to become an orthogonal technique to the existing explosive screening technologies for reducing the number of false positives/false negatives in a cost-effective manner.

Highlights

The 2011 Department of Homeland Security (DHS) Progress Report [1] on “Implementing 9/11 Committee Recommendations” places important precedence on improving national security through robust explosive screening technologies
The HC and nitrogen oxides (NOx) sensor responses deviated from their sensor baselines with sharp peaks
The anomalous baseline response is speculated to the outgassing of the polymer insulation on thermocouple wire that was attached to the surface of collector felt; this will be rigorously investigated in future work

Summary

Introduction

Mixed potential sensors are a class of electrochemical devices, which develop a non-Nernstian electromotive force (EMF) due to the difference in the kinetics of the redox reactions at each electrode/electrolyte interface upon exposure to various analytes [15,16,17]. Instead of external heating in a furnace, a commercial high temperature ceramic cofire (HTCC) approach was used to prepare sensors with platinum heaters integrated into a planar device structure. Due to this modification, a different sensor package configuration was used from previous work with the front end remaining the same.

Experimental

Results and Discussion

Conclusions