Membrane-Based Portable Colorimetric Gaseous Chlorine\nSensing Probe

Abstract

Highly toxic chlorine gas imposes\nserious health risks in the workplace.\nThe ability to on-site, real-time monitoring of instantaneous and\ntime-weighted average (TWA) chlorine gas concentrations in a simple,\nsensitive, accurate, and reliable manner would be highly beneficial\nto improve workplace health and safety. Here, we propose and experimentally\nvalidate a gaseous chlorine detection principle based on a <i>N</i>,<i>N</i>-diethyl-<i>p</i>-phenylenediamine\nsulfate salt/Cl₂ colorimetric reaction-controlled membrane\nprocess to regulate the gaseous chlorine transport across a gas-permeable\nmembrane that enables the establishment of a time-resolved analytical\nrelationship to quantify chlorine concentration by multidata points\nwith dramatically enhanced accuracy and reliability. A gas-permeable\nmembrane-based portable colorimetric gaseous chlorine sensing probe\n(MCSP) was designed and fabricated. The MCSP embedded the proposed\nanalytical principle that is capable of real-time continuous monitoring\nof the instantaneous and TWA chlorine gas concentrations within an\nanalytical range of 0.009–2.058 mg L^–1 without\nthe need for on-going calibration, which could be a useful analytical\ntool for managing the toxic chlorine gas-imposed health risks in workplaces.