A comparison of PMT-based and CCD-based sensors for electrochemiluminescence detection of sunset yellow in soft drinks

The use of artificial colorants in food is highly regulated due to their potential to harm human health. Thus, it is crucial to detect these substances effectively to ensure conformance with industrial standards. In this work, we prepared a photomultiplier tube (PMT)-based electrochemiluminescence (ECL) sensor and a charged coupled device (CCD)-based ECL sensor and compared their merits in the detection of sunset yellow (SY) dye. The sensors used C,N quantum dot-embedded g-C 3 N 4 nanosheets (QDs@NSs) as the ECL agent and K 2 S 2 O 8 as the coreactant. SY was analyzed on the basis of amplification in the QDs@NHs-K 2 S 2 O 8 ECL system. The PMT-based sensor realized ultrasensitive detection using a single electrode, especially at low concentrations of SY. A CCD-based sensor imaged the ECL phenomenon of an electrode array and provided the advantages of high throughput and time savings. Under optimized conditions, both sensors exhibited high specificity, reproducibility and stability; detection limits of 20 nM with PMT detection and 5 μM with CCD detection were determined for SY, with detection ranging over at least two decades. The practical feasibilities of these systems were confirmed by satisfactory detection of SY in real drink samples.