Unmanned aerial vehicle system for the extraction and electrochemical detection of explosives and explosive components in soils using filter paper and electrolyte
Inventors
Zabetakis, Daniel • Trammell, Scott A. • Dressick, Walter J. • Stenger, David A. • Verbarg, Jasenka
Assignees
Publication Number
US-9857293-B2
Publication Date
2018-01-02
Expiration Date
2034-08-27
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Abstract
Described herein is an approach using inexpensive, disposable chemical sensor probes that can be mounted on a small unmanned aerial vehicles (UAVs) and used to analyze a site (such as one known or suspected to contain explosive residue, spilled material or contaminated soil) without the need for a person to conduct ground operations at the site. The method involves contacting a soil or a surface with a filter paper wetted with a solvent, then subjecting the filter paper to voltammetry and/or spectroscopy, thus detecting a possible variation indicative of one or more analytes, wherein the solvent is the deep eutectic solvent consisting of a mixture of ethylene glycol and choline chloride.
Core Innovation
The invention provides a system and method for detecting explosives and explosive components in soils and surfaces using disposable chemical sensor probes mounted on unmanned aerial vehicles (UAVs). The system employs filter paper wetted with a deep eutectic solvent consisting of a mixture of ethylene glycol and choline chloride to extract analytes from soil or surfaces. Detection is conducted via voltammetry and/or spectroscopy on the filter paper following contact with the sampled site, enabling remote or on-board analysis without the need for personnel to be physically present at the sampling location.
The problem addressed by this invention arises from the limitations of existing explosives detection technologies in the field, particularly for time-sensitive military operations. Current methods such as deployable lab systems with liquid chromatography and mass spectrometry require significant logistical support and are impractical for rapid field use. Handheld devices generally require bulk samples not easily obtained, and remote sensing methods like laser standoff detection are limited by low sensitivity in soil environments. There is thus a strong need for a simple, rapid, reliable, and inexpensive field method capable of detecting explosives remotely without ground operations.
The innovation incorporates a combination of electrodes (often modified) and cellulose-based filter paper saturated with a suitable solvent that both extracts explosives from soils and acts as an electrolyte enabling electrochemical detection. The preferred solvent mixture, ethylene glycol and choline chloride, provides a deep eutectic solvent with low evaporation, enabling stable sample collection and analysis. This approach also allows for capillary movement of solubilized analytes to electrodes for voltammetry or spectroscopy, including in configurations integrated with UAV platforms for remote detection and communication of results.
Claims Coverage
The patent includes one primary independent claim covering a system integrating UAVs with a testing rig for explosives detection, presenting inventive features related to the components and functional configuration of the system.
System integrating UAV with a testing rig for explosive detection
A system comprising an unmanned aerial vehicle platform operably connected to a testing rig that includes filter paper, a deep eutectic solvent consisting of a mixture of ethylene glycol and choline chloride, and a testing device configured to perform voltammetry and/or spectroscopy on the filter paper after it contacts a soil or surface.
The independent claim covers a UAV-based detection system incorporating filter paper, a specific deep eutectic solvent, and testing means configured for electrochemical and/or spectroscopic analysis following environmental sampling. The inventive features focus on the integration of these components for remote explosives detection.
Stated Advantages
The ethylene glycol/choline chloride solvent is slow to evaporate, serving both as an electrolyte and solvent to extract explosive components from soil.
The filter paper saturated with solvent allows soil sampling via UAV without fouling electrodes, which was unexpected.
Detection is possible in air-saturated solvents, eliminating the need to purge oxygen, simplifying fieldwork.
The filter paper's wicking property removes interfering electrochemical signals, enhancing trace explosives detection.
The system enables on-board or remote analysis with automated result communication.
Documented Applications
Remote electrochemical detection of explosives and explosive components in sites known or suspected to contain explosive residue, spilled material, or contaminated soil using UAVs.
Detection of other chemicals of interest such as illicit drugs, nerve agents, toxic industrial compounds, biologicals, and other electrochemically active analytes.
Sampling and detection of nitrates and trinitrotoluene (TNT) in various soils and sands using UAV-mounted testing rigs.
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