Detection Papers with Chromogenic Chemosensors for Direct Visual Detection and Distinction of Liquid Chemical Warfare Agents

Vladimír Pitschmann,Michal Dymák,Lukáš Králík,Lukáš Matějovský,Martin Urban,Kamila Lunerová

doi:10.3390/chemosensors7030030

Abstract

This work provides a summary of our results in the area of the experimental development of detection paper for the detection of liquid phase chemical warfare agents (drops, aerosol), the presence of which is demonstrated by the development of characteristic coloring visible to the naked eye. The basis of the detection paper is a cellulose carrier saturated with the dithienobenzotropone monomer (RM1a)–chromogenic chemosensor sensitive to nerve agents of the G type, blister agent lewisite, or choking agent diphosgene. We achieve a higher coloring brilliance and the limit certain interferences by using this chemosensor in the mix of the o-phenylendiamine-pyronine (PY-OPD). We prove that the addition of the Bromocresol Green pH indicator even enables detection of nerve agents of the V type, or, nitrogen mustards, while keeping a high stability of the detection paper and its functions for other chemical warfare agents. We resolve the resistance against the undesirable influence of water by providing a hydrophobic treatment of the carrier surface.

Highlights

Even though the Chemical Weapons Convention came into operation in 1997, and currently 193 countries participate, the risk of chemical weapons proliferation and the threat of using them is still present: They can be used in local wars, civil wars, or in terrorist attacks [1,2].The active components of the chemical weapons are the chemical warfare agents (CWA), the combat employment of which depends to a significant extent on their state of matter
The first design of the novel detection paper was based on the intention of developing a detection paper with high selectivity for G type nerve agents, for which detection using existing technical means is an issue
E.g., the 3-way detection papers (M8, PDF-1, PP-3, CALID-3, and similar) provide a relatively faint yellow color with the G type nerve agents droplets, which is disturbed with the presence of common organic solvents and industrial chemicals; the M9 detection paper provides an even lower selectivity as we verified the selectivity of these means experimentally

Summary

Introduction

The active components of the chemical weapons are the chemical warfare agents (CWA), the combat employment of which depends to a significant extent on their state of matter. CWAs that have lethal effects are included within nerve agents, blister agents, and partially within choking agents. CWAs are highly persistent, they can contaminate the terrain for a long time, depending on actual climatic conditions and on the terrain characteristics [3].

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