Cellulose Acetate–Cellulose Nanowhisker Nanocomposite Immobilized with a DCDHF-Hydrazone Chromophore toward a Smart Test Strip for Colorimetric Detection of Diethyl Chlorophosphate as a Nerve Agent Mimic

Abstract

Exposure to nerve agents, which are usually colorless and odorless gases, may cause organ failure, paralysis, or even quick death. Diethyl chlorophosphate (DCP) has been recognized as one of the most well-known chemical warfare nerve agent mimics. In the current study, we introduce a simple strategy for the development of a portable and reversible nanocomposite-based microporous strip for naked-eye detection of DCP within a few seconds. A dicyanomethylenedihydrofuran hydrazone (DCDHF-H) chromophore was synthesized by an easy azo-coupling reaction and encapsulated in situ during the preparation of cellulose acetate/cellulose nanowhisker/hydrazone (CA-CNW-H) nanocomposites. These CA-CNW-H nanocomposites displayed a bathochromic shift in the absorption intensity of about 142 nm from 438 to 580 nm with the increase of the DCP concentration. The present CA-CNW-H sensor strip displayed a detection limit for DCP ranging from 25 to 200 ppm. The color change of CA-CNW-H from yellow to purple due to exposure to DCP was detected by CIE Lab analysis. The morphology, fibrous crystallinity, thermal stability, and mechanical properties of the prepared CA-CNW-H sensor strips were investigated.

Metallochromic Hydrazone‐Based Chemosensor with Application in a Colorimetric Paper Strip for Selective Detection of Cu2+

“…L * was highly decreased upon raising the total content of the copper ions to indicate the formation of darker color. a * was increased and switched from negative to positive values representing a colorimetric change from green to red, whereas b * decreased and switched from +b * to −b * to designate a colorimetric change from yellow to blue [32–34] …”

“…L* was highly decreased upon raising the total content of the copper ions to indicate the formation of darker color. a* was increased and switched from negative to positive values [32][33][34] Many colorimetric chemosensors have been developed for detection of copper ions, such as Schiff-Bases, [35] pyrenes, [36] chromones, [37] and metal-organic frameworks. [38] However, these chemosensors have shown disadvantages, such as sophisticated and expensive preparation procedures, poor selectivity, lower limit of detection, and difficult to operate under ambient conditions.…”

Development of novel reversible thermometer from N‐isopropylacrylamide and dicyanodihydrofuran hydrazone probe

“…DCDHFH have been used as a halochromic, vapochromic, metallochromic, solvatochromic, biochromic, thermochromic sensing tools. [43,52,53] The UV-Vis absorption spectra of the produced chromophore showed that it has solvatochromic and halochromic capabilities. The introduction of electron-withdrawing groups on the phenylhydrazone group improved the molecular polarizability of the DCDHFH.…”

Preparation of microfibrillated cellulose/polyvinyl alcohol test strip integrated with novel chemosensor for colorimetric determination of diisopropyl fluorophosphate

“…The PVA-MFC-H film with the highest content of TCF-hydrazone displayed a weight loss monitored at 495 C. It can be concluded that the immobilization of the organic TCF-hydrazone in the PVA-MFC films results in increasing the rate of pyrolysis. [21,37] It was found that because of the increased weight loss of the QHTCF-immobilized PVA-MFC strips in comparison to the QHTCF-free PVA-MFC strip, their thermal stability was less than that of PVA-MFC. The remaining weight of the PVA-MFC film was controlled to around 18%.…”

“…There are many methods have been reported to detect nerve agents, including enzymatic, surface acoustic wave, electrochemical, and fluorescent approaches. [20][21][22] These techniques, on the other hand, were sluggish, nonselective, less sensitive, lacking in specificity, and prohibitively costly to use. The usage of electrical and electric components and highly trained employees may also be required.…”