Determination of bromate via the chemiluminescence generated in the sulfite and carbon quantum dot system

Abstract

The authors describe a chemiluminescence (CL)-based assay for the determination of bromate. The method is based on the use of a solution of carbon quantum dots (CQDs) and sulfite. Strong CL (peak at 490 nm) is observed when bromate is injected into the solution. The CL increases linearly in the 0.3 to 10 μmol L bromate concentration range, giving a 0.1 μmol L limit of detection (at an S/N ratio of 3). A possible CL mechanism is suggested that involves a redox reaction between the CQDs, bromate and sulfite in the acidic medium. This leads to the formation of hole-injected and electron-injected CQDs. Radiative recombination of oxidant-injected holes and electrons in the CQDs accounts for the occurrence of CL. This mechanism contradicts the previous assumption that the transfer of energy occurs from SO* to the CQDs. Although nitrite may interfere in the determination of bromate, its effect can be eliminated by adding sulfamic acid. The assay is sensitive and represents a new tool for the determination of bromate, which is a carcinogen. Graphical abstract Under acidic condition, carbon quantum dots (CQDs) can react with sulfite and bromate transforming to hole-injected CQDs (CQDs) and electron-injected CQDs (CQDs), respectively. Thereafter, strong chemiluminescence (490 nm) aroused from the radiative electron-hole annihilation between CQDs and CQDs.

Quantum dots‐based chemiluminescence probes: an overview

“…The annihilation of CDs •− and CDs •+ generated excited CDs * , from which the final CL emission originated. Cheng and colleagues reported that CQDs <Author: Please give abbreviation CQDs in full.>could react with sulfite and bromate under acidic conditions, resulting in hole‐injected CQDs (CQDs •– ) and electron‐injected CQDs (CQDs •+ ), respectively, producing strong CL (490 nm) from radiative EHA between CQDs •– and CQDs •+ …”

Versatile Aerogels for Sensors

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A tetrahedron-shaped polyoxoantimotungstate encapsulating a hexanuclear octahedral lanthanide-oxo cluster for an amperometric bromate sensor

“…Currently, various materials have been applied in electrochemical analysis methods for the detection of bromate. Examples include organic polymers, 7 metal complexes, 8,9 carbon quantum dots (CQDs), 10 metal nanoparticles, 6,11 metal oxides, 12,13 polyoxometalates 14 and so on. Among these materials, polyoxometalates have received much attention in recent years due to their excellent redox properties.…”