Research Highlights

Technology Performance Summary: Severn Trent Services Eclox™ Strip for Chemical Warfare Agents

All Hazards Receipt Facilities (AHRFs) were developed to prescreen for chemical, radiochemical, and explosive hazards in samples collected during suspected terrorist attacks. The technologies used in AHRFs are intended to screen samples prior to a full analysis, helping protect responders, laboratory workers, and others from potential injury.

Evaluations of these technologies are summarized in the technology evaluation report, Testing of Screening Technologies for Detection of Chemical Warfare Agents in All Hazards Receipt Facilities. The chemical warfare agents (CWAs) included in the report were chosen because they might be used during, or develop as a by-product from, a terrorist attack.

The screening technologies are intended:

• To be rapid and qualitative
• To be simple to use and of relatively low cost
• To indicate if samples contain hazardous chemicals of concern.

Not all of the technologies evaluated were deemed suitable for the AHRF, although they might be useful for responders on the scene.

Technology Evaluated: Severn Trent Services Eclox™ Strip

Sample Types Evaluated for Indication of: Nerve agents sarin and VX in liquid

Conclusions:
The Severn Trent Services Eclox™ Strip:

• Reliably detected sarin and VX in deionized (DI) water (i.e., 100% accuracy).
• May or may not have capabilities to detect sarin and VX in isopropyl alcohol (IPA) samples, since it gave false positive responses to blank solvent samples.
• Response time was 3 minutes because of the reaction time needed for color change.
• Uses a relatively simple procedure.

Technology Description and Requirements: Enzyme-based reagent. This technology is a nerve agent detection ticket based on acetylcholinesterase inhibition, designed for water sample screening. The technology uses two reagent pads under a foil protective covering. To use the ticket, the foil covering is removed and one of the reagent pads is wetted with the sample and then pressed against the second pad. A white color on the first pad indicates the presence of a nerve agent; a blue color indicates no agent is present. The test strips are part of the Hach Eclox™ Water Test Kit.

Testing Methodology and Results: Stock solutions of sarin, sulfur mustard, and VX were diluted in IPA or DI water to make the samples. The detection device was tested with three blank samples of the solvent used (IPA or DI water), and three samples of the test solution containing the CWA. If the instrument detected the CWA in at least one of the three tests with pure solvent, then the challenge was repeated with a hydrocarbon mixture interferent (1% of the total volume) added to both the blank and the CWA samples. Table 1 lists the CWAs tested, the concentrations used and the basis for those concentrations. All liquid sample testing was conducted at room temperature with 50% relative humidity. The pesticide strip color tickets were tested by wetting the appropriate reagent pad with the liquid sample.

Table 1: Summary of Severn Trent Services Eclox™ Strip Results

^aA hydrocarbon mixture was used as the interferent.
^bDI water or IPA was used as the solvent in the liquid test.
^cRDT&E = Research, Development, Test, and Evaluation Standards (Chemical Surety, Chapter 6: Army Regulation 50-6, 26 June 2001).
^dTechnology also gave positive responses to blank solvent

Contact: Eric Koglin

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