Field Quantification of Hydroxyl Radicals by Flow-Injection Chemiluminescence Analysis with a Portable Device

Abstract

Hydroxyl radical ( • OH) is a powerful oxidant abundantly found in nature and plays a central role in numerous environmental processes. On-site detection of • OH is highly desirable for real-time assessments of • OH-centered processes and yet is restrained by a lack of an analysis system suitable for field applications. Here, we report the development of a flow-injection chemiluminescence analysis (FIA-CL) system for the continuous field detection of • OH. The system is based on the reaction of • OH with phthalhydrazide to generate 5-hydroxy-2,3-dihydro-1,4phthalazinedione, which emits chemiluminescence (CL) when oxidatively activated by H 2 O 2 and Cu 3+ . The FIA-CL system was successfully validated using the Fenton reaction as a standard • OH source. Unlike traditional absorbance-or fluorescence-based methods, CL detection could minimize interference from an environmental medium (e.g., organic matter), therefore attaining highly sensitive • OH detection (limits of detection and quantification = 0.035 and 0.12 nM, respectively). The broad applications of FIA-CL were illustrated for on-site 24 h detection of • OH produced from photochemical processes in lake water and air, where the temporal variations on • OH productions (1.0−12.2 nM in water and 1.5−37.1 × 10 7 cm −3 in air) agreed well with sunlight photon flux. Further, the FIA-CL system enabled field 24 h field analysis of • OH productions from the oxidation of reduced substances triggered by tidal fluctuations in coastal soils. The superior analytical capability of the FIA-CL system opens new opportunities for monitoring • OH dynamics under field conditions.

Black Phosphorus Quantum Dots with Exposed (113) Planes on Chemiluminescent Luminol–K3Fe(CN)6 for Detection of Dopamine

“…Chemiluminescence (CL) technology has been extensively used in the domain of analysis due to its high sensitivity, simple instrumentation, and absence of background scattered light for detecting trace level metal ions, inorganic compounds, and small biological molecules. − Although many technologies have been applied in the field of detection, the CL method exhibits higher sensitivity due to the low background emission. Whereas, traditional CL systems are limited in practical applications due to the low inherent signal and poor selectivity.…”