An Optical Dosimeter for the Selective Detection of Gaseous Phosgene with Ultralow Detection Limit

Abstract

We present here a cheap, fast, and highly selective dosimeter for the colorimetric detection of gaseous phosgene with an ultralow detection limit. The disposable device is based on Harrison's reagent supported into a porous nanocrystalline TiO matrix film. We exposed the films to phosgene streams while the absorbance was monitored by an optic fiber in a gas chamber. The pronounced spectral changes were unaffected by humidity and oxygen and permitted us to use the response rate at 464 nm as a very stable calibration signal for quantitative analysis purposes. The use of a specific sensing reaction guaranteed a very high selectivity of the device even against saturated vapors of primary interferences like halide gases and other oxidizing and volatile agents. With this simple method, whose response is compatible with affordable and efficient miniature LED-photodiode devices, we reach an ultralow limit of detection well below the ppm level.

Second-Generation Phosgene and Diphosgene Detection Tube

“…Apart from technically advanced physical and physico-chemical detectors and analysers, attention is paid to rapid, simple, and inexpensive detection methods for phosgene/diphosgene in air based on color reactions using detection papers, strips, chalks, and detection tubes [2]. The traditional procedures and methods are based on a nucleophilic substitution reaction (acylation) of phosgene/diphosgene with analytical reagents such as p-dimethylaminobenzaldehyde [3][4][5], 4,4 -bis(dimethylamino)benzophenone [6,7], 4-(p-nitrobenzyl)pyridine [8,9], or anabasine [10]. A number of novel reagents providing colored reaction products that exhibit visible, often predominating fluorescence were developed during the past decade.…”

An amino-substituted 2-(2′-hydroxyphenyl)benzimidazole for the fluorescent detection of phosgene based on an ESIPT mechanism

“…Nowadays, fluorescent detection methods are well developed and widespread due to their easy manipulation, fast response, high sensitivity and selectivity, and the possibility of real-time detection. Among them, reports on the fluorescent detection of phosgene are still limited 12–14 and mainly based on: (i) twice carbamylation reactions of fluorescence probes, which employ o -phenylenediamine, 21 o -hydroxyaniline, 22 o -aminobenzyl amine, 23 catechol, 24 ethylenediamine, 25 ethanolamine 26 or other moieties 27 as reactive site; (ii) phosgene-promoted dehydration reaction of fluorescence probes, which employ oxime 28 or amide 29 as reactive site; and (iii) several other phosgene-induced reactions, including intermolecular reaction of two fluorophores, 30 intramolecular reaction of cinnamic acids, 31 ring opening reaction of benzimidazole-fused rhodamine dye 32 and Beckmann rearrangement of ketoxime 33 (Table S2 † ). However, most of these fluorescence probes are based on mechanisms of photoinduced electron transfer (PeT), intramolecular charge transfer (ICT) or aggregation-induced emission (AIE), which might be disturbed by acetylating, 21 c phosphorylating agents 21 h or oxidizing chemicals, 21 e ,27 g resulting to false response.…”

Graphene Nanobuds: A New Second-Generation Phosgene Sensor with Ultralow Detection Limit in Aqueous Solution

“…In the past, many materials and conventional methods such as high-performance liquid chromatography (HPLC), gas chromatography (GC), and Raman spectroscopy have been utilized to determine phosgene through different principles. − However, these conventional analytical techniques require complicated sample preparation, usually involving a preconcentration step prior to the analysis, and have many disadvantages, for instance, limited portability and expensiveness . In recent times, numerous fluorescent/colorimetric chemosensors for phosgene in gas and liquid phases of organic solutions have been developed based on diverse mechanisms; by and large, this is due to their high selectivity, rapid and sensitive detection, low cost, and easy handling. ,,− These fluorescent and colorimetric chemosensors are termed as first-generation sensors, and lately, Yoon et al named benzimidazole-fused rhodamine dye embedded nanofibers as second-generation sensors due to the shortage of the first-generation phosgene sensors . Although a few reports exist on fluorescent sensing of other highly toxic chemicals, explosives, and chemical warfare agents in aqueous solution, , none is available for phosgene.…”