Second-Generation Phosgene and Diphosgene Detection Tube

Vladimír Pitschmann,Sylvie Pavloková,Zdeněk Moravec,David Vetchý,Martin Lobotka,Lukáš Matějovský,Michal Dymák,Jiří Zeman

doi:10.3390/chemosensors8040107

Abstract

We have developed a second-generation detection tube for colorimetric and fluorescence detection of phosgene and diphosgene in air. The tube is packed with pellets made of a mixture of microcrystalline cellulose and magnesium aluminum metasilicate treated with a suitable monoterpene (camphor, menthol) to increase porosity and specific surface area. We impregnated the pellets with a specific o-phenylenediamine-pyronin (PY-OPD) based reagent. The detector with this novel indication charge enables phosgene or diphosgene to be selectively and sensitively detected at concentrations lower than as would those posing acute health risk. Owing to the analytical colorimetric and, at the same time, fluorescence signal, the detector is very robust while featuring good sensitivity and variability. The colorimetric limits of detection were 0.3 mg/m3 (tristimulus colorimeter), resp. 5 mg/m3 (with the naked eye), fluorescence detection limits of 0.3 mg/m3 (with the naked eye), all at an air sample volume of 1 dm3. The response was practically immediate, acid vapors and gases, or diethyl chlorophosphate as a simulant of nerve warfare chemical agents, were disruptive.

Highlights

Phosgene and diphosgene are toxic compounds that damage the alveolar air/capillary air–blood barrier in the lungs
Materials used for the preparation of carriers included menthol (Dr Kulich Pharma, Hradec Králové, Czech Republic), camphor (Dr Kulich Pharma, Hradec Králové, Czech Republic), magnesium aluminum metasilicate (Neusilin® US2, Fuji Chemical Industry, Toyoma, Japan), microcrystalline cellulose (Avicel® PH-101, FMC Biopolymer, Wallingstown, Ireland), microcrystalline cellulose and sodium carboxymethylcellulose (Avicel® RC-581, FMC Biopolymer, Brussels, Belgium), o-phenylenediamine-pyronin (PY-OPD, synthesized by the University of Chemistry and Technology, Prague, Czech Republic; the spectral data corresponded to the literature), chloroform (Merck, Darmstadt, Germany), and purified water
Other past experiments were aimed at increasing the pellet’s sorption capacity by adding magnesium aluminum metasilicate; such carriers were used in cholinesterase detection tubes serving to identify nerve chemical warfare agents [28,29]

Summary

Introduction

Phosgene (carbonyl dichloride) and diphosgene (trichloromethyl chloroformate) are toxic compounds that damage the alveolar air/capillary air–blood barrier in the lungs. Phosgene is an important industrial chemical in the organic synthesis domain. Both phosgene and diphosgene were one of the main types of chemical warfare agents used (CWA). Chemosensors 2020, 8, 107 in the deployment of major chemical weapons, mainly during World War I. Phosgene is listed on Schedule 3 of the Chemical Weapons Convention. Hazards may arise from phosgene and, partly, diphosgene leaks during chemical industrial accidents and from civil wars and terrorist attacks in which the compounds are used as efficient chemical weapons

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Results

Conclusion