Chemiluminometric Measurement of Atmospheric Ozone with Photoactivated Chromotropic Acid

Abstract

A highly sensitive, robust, fast, affordable measurement system based on interfacial gas-liquid chemiluminescence (CL) on a wetted transparent screen directly on top of a miniature photomultiplier tube provides the basis of an attractive method for ozone (O(3)). Alkaline chromotropic acid (CA, 4,5-dihydroxynaphthalene-2,7-disulfonic acid) chemiluminesces upon exposure to ozone. No light emission is observed from exposure of alkaline CA to NO(2) or H(2)O(2). However, response to ozone is highly dependent on the age and storage condition of the CA solution. As such, quantitative analysis will require frequent calibration, and the method will not be attractive. We have discovered that photoactivation plays the key role in producing (a) compound(s) from chromotropic acid that appear(s) to be the primary agent(s) responsible for the CL reaction with O(3). We thus devised a method wherein a flowing solution of CA (that is stable in neutral/acidic solutions) is rendered alkaline and then exposed for a few seconds on-line to UV radiation. The solution then reacts with ozone on a screen consisting of an "invisible" nylon stocking that provides for low liquid residence time and high light throughput and results in an LOD of 40 pptv, a determination range at least up to 230 ppbv, and 10-90% and 90-10% response times of 130 and 80 ms, respectively. Intra- and interday repeatabilities at the same concentration were 0.32 and 3.8% in relative standard deviation. On the basis of aging, CL, chromatography, and chromatography-mass spectrometry studies, we suggest that the primary CL-active species are likely dimeric semiquinone species derived from CA by a series of radical reactions.

A fast and precise chemiluminescence ozone detector for eddy flux and airborne application

“…Major advantages are their small signal drift (compared to dry CI technqiues) and absence of water vapour cross-sensitivities (Takayanagi et al, 2003).…”

High-Sensitivity Ozone Sensing Using 280 nm Deep Ultraviolet Light-Emitting Diode for Detection of Natural Hazard Ozone

“…Ozone sensing using a Hg lamp was used for the purpose of solar-blind sensing in the aerospace industry [6,7]. Researchers have also applied UV light to the chemiluminometric measurement of atmospheric ozone [8]. There have been attempts to use optical fibers for sensing [9].…”

Development of Technologies for Sensing Ozone in Ambient Air

“…The chemiluminescence (CL) method is used to detect ozone when a fast response time is needed. [44][45][46][47][48][49][50][51][52][53][54] A large amount of effort has been devoted to investigating materials showing ozone-induced CL effectively, and to fabricate sensor devices that dispense with manual operation.…”