Separation and pre-concentration of Sunset Yellow in beverages and effervescent vitamin C tablets by a new flotation technique prior to spectrophotometric determination

Fabrication of 3D CuFe2O4/Cu0 hierarchical nanostructures on carbon fiber paper by simple hydrothermal method for efficient detection of malachite green, sunset yellow and tartrazine in food samples

In this study, a hydrothermal process was utilized to grow mixed-valence CuFe2O4/Cu0 nanosheets on carbon fiber paper, forming a three-dimensional hierarchical electrode (CuFe2O4/Cu0@CFP). The ordered array structure, coupled with the porous bowl-like structure, enhances the exposure of more electrode active sites and facilitates analyte penetration, thus enhancing the electrode sensing performance. As a binder-free sensor, the CuFe2O4/Cu0@CFP sensor exhibited remarkable sensitivity in detecting Malachite Green (MG), Sunset Yellow (SY) and Tartrazine (TA) over wide concentration ranges: 0.1-300 μM for MG (R2 = 0.994), 0.005-200 μM for SY (R2 = 0.996), and 0.005-300 μM for TA (R2 = 0.995) with low detection limits of 0.033 μM for MG, 0.0016 μM for SY, and 0.0016 μM for TA (S/N = 3), respectively. Additionally, the 3D CuFe2O4/Cu0@CFP sensor detected MG, SY, and TA in a mixed solution with satisfactory results. It also performs well in beverage, fruit juice powder, and jelly samples, with results matching those from HPLC.

Do effervescent vitamin tablets affect the surface roughness, microhardness, and color of human enamel and contemporary composite resins?

PURPOSE

To compare the impact of four effervescent vitamin tablets on the surface roughness, microhardness, and color of human enamel and contemporary composite resins.

MATERIAL AND METHODS

Sixty enamel and a total of 240 anterior (Gradia Direct Anterior), posterior (Gradia Direct Posterior), and universal composite resin (Filtek Ultimate) specimens (n = 60 per group) were fabricated. Each group was subdivided into five subgroups (n = 12, per subgroup). The specimens were subsequently immersed in YOUPLUS, Redoxon, Sunlife Immuvit, and Sambucol effervescent vitamin solutions for 2 min per day over 30 days. Distilled water was used as control. Subsequently, surface roughness (Ra) was detected using a profilometer, and microhardness (VHN) was measured using a microhardness tester. A spectrophotometer device was used to record the L,a,b color coordinates of the specimens after 24 h, 7 days, and 30 days, and the color changes (ΔE00) of the groups were calculated. The data were analyzed by ANOVA, two-way ANOVA, Kruskal-Wallis, Levene's, and Fisher's least significant difference (LSD) tests (p < 0.05). SEM analysis was conducted on one randomly selected specimen per group (×1000).

RESULTS

In terms of surface roughness, material X vitamin interactions were found significant (p < 0.05). The increase in Ra from 24 h to 30 days was found significant (p < 0.05) except for Gradia Direct Anterior X Redoxon, Sunlife Immuvit and Sambucol, Filtek Ultimate X Sunlife Immuvit and Sambucol, and all control groups. Ra changes were also concluded by SEM. Regarding VHNs, material X vitamin interactions were significant (p < 0.005), except for all Filtek Ultimate subgroups. The changes in VHNs of the groups from 24 h to 30 days were significant for all enamel and Gradia Direct Anterior X YOUPLUS, Gradia Posterior X YOUPLUS, Sunlife Immuvit, and Sambucol groups (p < 0.05). In terms of ΔE00, significant differences were observed between the 7 days and 30 days in the enamel (p = 0.047), Gradia Direct Anterior (p = 0.019), and Gradia Direct Posterior groups (p = 0.038).

CONCLUSIONS

Daily consumption of effervescent vitamin tablets can increase surface roughness, decrease microhardness, and influence the color of human enamel and contemporary anterior, posterior, and universal composite resins after a 30-day period.

Voltammetric Sensor Based on the Combination of Tin and Cerium Dioxide Nanoparticles with Surfactants for Quantification of Sunset Yellow FCF

Sunset Yellow FCF (SY FCF) is one of the widely used synthetic azo dyes in the food industry whose content has to be controlled for safety reasons. Electrochemical sensors are a promising tool for this type of task. A voltammetric sensor based on a combination of tin and cerium dioxide nanoparticles (SnO2-CeO2 NPs) with surfactants has been developed for SY FCF determination. The synergetic effect of both types of NPs has been confirmed. Surfactants of various natures (sodium lauryl sulfate (SLS), Brij® 35, and hexadecylpyridinium bromide (HDPB)) have been tested as dispersive media. The best effects, i.e., the highest oxidation currents of SY FCF, have been observed in the case of HDPB. The sensor demonstrates a 4.5-fold-higher electroactive surface area and a 38-fold-higher electron transfer rate compared to the bare glassy carbon electrode (GCE). The electrooxidation of SY FCF is an irreversible, two-electron, diffusion-driven process involving proton transfer. In differential pulse mode in Britton-Robinson buffer (BRB) pH 2.0, the sensor gives a linear response to SY FCF from 0.010 to 1.0 μM and from 1.0 to 100 μM with an 8.0 nM detection limit. The absence of an interferent effect from other typical food components and colorants has been shown. The sensor has been tested on soft drinks and validated with the standard chromatographic method.

A new ratiometric molecularly imprinted electrochemical sensor for the detection of Sunset Yellow based on gold nanoparticles

Since a high dosage or excessive intake of Sunset Yellow (SY) may pose a threat to human health, it is in great demand to construct an effective method to detect and control SY. Based on the molecularly imprinted polymers (MIPs) and dual-signal output mode, a ratiometric molecularly imprinted electrochemical sensor (RMIECs) was developed for sensitive detection of SY. AuNPs not only provided a large specific surface area to enhance the electron transfer rate but also served as a reference signal (S1), together with SY signal (S2), to produce dual signals. For a proof-of-application study, RMIECs was applied to detect SY with a wide linear range from 10 nM to 100 μM and a low detection limit (LOD) of 1.60 nM (S/N = 3, n = 3). Besides, the method was applied in spiked food samples with recoveries of 94.0 ∼ 97.0 % as well as relative errors of 5.4 ∼ 8.3 %, revealing its promising potential in detection of SY.

Rapid Determination of Sunset Yellow in Soft Drinks Using Silicon Nanoparticles Synthesized under Mild Conditions

Sunset yellow (SY) is a synthetic colorant which can cause allergies, diarrhea and other symptoms in sensitive people. When ingested too much, it can accumulate in the body and cause damage to the kidneys and liver. Therefore, the content of SY in food must be strictly controlled. In order to regulate their use and ensure food quality, simple and cost-effective methods need to be developed to identify them. In this experiment, fluorescent silicon nanoparticles (SiNPs) were prepared by a one-step method, which is simple, mild and less time-consuming. The fluorescent SiNPs prepared had good thermal stability, excellent salt resistance and pH stability. SY effectively quenched the fluorescence of SiNPs by fluorescence resonance energy transfer when added to the system as an interfering substance. The method had a good linear relationship in the range of SY concentration of 0.050 - 14.0 μg mL^-1 and the detection limit is 0.023 μg mL^-1. The established sensor was applied to the detection of SY in beverages, and the recovery rate was 93.8 - 102.4%. Based on the excellent selectivity and sensitivity of the method, it could provide a convenient way for the detection of SY in food samples.

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.

Quantification of permitted synthetic colours in food by liquid chromatographic methods: a review on analytical methods and their performance

Colours, natural and synthetic, are substances which add or restore colour to a food after processing or storage. They are widely used by food manufacturers but may pose a potential risk to human health. Most food safety authorities set up regulations to limit the use of synthetic colours, and monitor their levels and consumption by the general public. Therefore, validated analytical methods are needed to fulfil this requirement. This review presents a comprehensive overview of various liquid chromatographic methods used for quantification of permitted synthetic colours in foods. Available analytical methods have been assessed for their fitness for purpose in terms of extraction, clean-up, liquid chromatographic separation, quantification and method performance. The advantages and disadvantages are given of available analytical methods for analysing 24 synthetic colours, permitted for use by different jurisdictions. Gaps in the knowledge and levels of validation are identified and recommendations made on further research to develop suitable methods for routine monitoring of these permitted synthetic colours.

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-C₃N₄ nanosheets (QDs@NSs) as the ECL agent and K₂S₂O₈ as the coreactant. SY was analyzed on the basis of amplification in the QDs@NHs-K₂S₂O₈ 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.