Use of flow injection analysis with chemiluminescence detection for determination of sunset yellow (E110) in drink samples

A modified electrode based on a 3D reduced graphene oxide and MoS2 composite for simultaneous detection of sunset yellow and tartrazine

A 3D reduced graphene oxide (3DrGO) composite loaded with cauliflower-like MoS2 was prepared. Benefiting from the synergistic effects of 3DrGO and cauliflower-like MoS2, a glassy carbon electrode (GCE) modified with the 3DrGO-MoS2 composite (3DrGO-MoS2/GCE) displays high sensing performance for sunset yellow (SY) and tartrazine (TZ) at working potentials of 0.795 and 1.034 V. Furthermore, a well separated oxidation peak potential can achieve simultaneous detection of the two analytes. Under selected conditions, the peak current exhibits a piecewise linear relationship with the SY concentration in the range of 0.05-10 μmol L-1 and 10-60 μmol L-1, and the plot of peak current versus the TZ concentration also exhibits two linear segments in the range of 0.1-6.0 μmol L-1 and 6.0-60 μmol L-1. The detection limits of SY and TZ are as low as 17.6 and 37.4 nmol L-1, respectively. The prepared 3DrGO-MoS2/GCE was applied for the determination of SY and TZ in food samples with excellent recoveries of 95.1-105.4%.

Gram-scale synthesis of nitrogen-doped carbon dots from locusts for selective determination of sunset yellow in food samples

Locust powder was converted into water-soluble fluorescent nitrogen-doped carbon dots (N-CDs) with gram-scale yield through a self-exothermic reaction between nitric acid and diethylenetriamine (DETA) within 10 min. The morphology, elemental information, and optical properties of the N-CDs were characterized using high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared, ultraviolet-visible and fluorescence spectroscopy. Spectroscopic investigation indicated that the fluorescence emission behaviour of N-CDs is excitation wavelength dependent, with the strongest emission peak at 470 nm using a 390 nm excitation wavelength. The strong absorption peak of sunset yellow (SY) at 482 nm overlaps substantially with the blue emission peak (470 nm) of N-CDs. This enables the fluorescence emission of N-CDs to be obviously quenched by SY through the inner filter effect. There was a good linear relationship between the fluorescence quenching degree and the concentrations of SY within the range 0.5-40 μM. The detection limit of developed fluorescence assay for SY is 28 nM, and the relative standard deviation is 2.3% (c = 10 μM). The N-CDs derived from locusts by the self-exothermic reaction are highly selective and sensitive fluorescent probes for SY, which were applied to the fluorescence sensing of SY in different food samples with satisfactory results.