Instant detection of picric acid vapour by developing layer by layer polymer detectors and an electronic prototype

Abstract

Detection of ultra-trace amount of picric acid have attracted substantial efforts from the perspective of health, safety and environment. Due to very low vapour pressure, the detection of picric acid vapour is quite challenging in comparison to that of the liquid phase. In this work, we have overcome this problem by developing layer by layer polymer detectors and an electronic prototype for instant detection of ppm level concentration of picric acid vapour via impedance spectroscopy. The detectors constitute of mainly two polymer layers with poly-cholesteryl methacrylate sulfonated hexene as the two outer layers and copolymer of 2-vinyl pyridine with acrylonitrile as the middle layer. In presence of the analyte, the detectors undergo steep decrease in impedance within few seconds. The thickness of the individual polymer layers play a vital role and it was observed that the detector with thinner outer layers (0.25 mm) is more efficient as it shows about 99 % decrease in the impedance for 0.334 ppm of picric acid vapour within 10 seconds. The method is selective, the effect of varying humidity is negligible and the detection limit was found to be 0.006 ppm. Moreover, the detectors show reproducible results and are also consistent for a long period. Using these detectors, we have designed an electronic prototype for visual detection of picric acid at room temperature. Unlike other sophisticated techniques the prototype is simple, portable, cost effective and can be used for detection of such higher explosives due to various implications such as homeland security, forensic and criminal investigations and remediation of explosive manufacturing sites. Please do not adjust margins Please do not adjust margins quadrupole resonance, 25 amperometry, 26 gas chromatography coupled with a mass spectrometer 27 etc. Although, Scheme-1: Schematic representation of the chemical structure of PA and the protocol for the detection of PA vapour using LBL detectors via impedance (Z) measurements with time and the electronic prototype for visual detection of such chemicals. Impedance (Z) measurements of the LBL detectors in presence of NACs were performed in HIOKI 3532-50, LCR Hi-TESTER. Results and discussion3.1 Fabrication of the detectors and working mechanism: To fabricate the monolayer polymer detectors, the polymers P2VP-Co-

Triarylamine‐Cored Dendritic Molecular Gel for Efficient Colorometric, Fluorometric, and Impedometeric Detection of Picric Acid

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