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In this study, a hydrothermal process was utilized to grow mixed-valence CuFe 2 O 4 /Cu 0 nanosheets on carbon fiber paper, forming a three-dimensional hierarchical electrode (CuFe 2 O 4 /Cu 0 @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 CuFe 2 O 4 /Cu 0 @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 (R 2  = 0.994), 0.005-200 μM for SY (R 2  = 0.996), and 0.005-300 μM for TA (R 2  = 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 CuFe 2 O 4 /Cu 0 @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., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An economically viable and greener approach is introduced to fabricate red emissive carbon dots (R@CQDs) via employing hydrothermal means on Hibiscus rosa-sinensis leaves as precursor source. The obtained R@CQDs displayed excitation-dependent behavior, with high aqueous stability, quantum yield of 56%, and outstanding fluorescence aptitude under the conditions of varied range of ionic strength and pH (1-12). The fluorescence emission behavior of R@CQDs displayed selective turn off fluorescence response to tartrazine over other interfering species with a limit of detection of 0.09 µM and quantitation limit of 0.30 µM. Theoretical calculations employing density functional theory (DFT) were carried out to complement experimental findings and getting insights into the underlying mechanism governing the sensing of tartrazine. The developed sensor holds significant potential for tartrazine detection in real samples and offering wider prospective in the food safety assessment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)

A facile hydrothermal route was employed for the synthesis of iron-nickel bimetal organic frameworks (Fe-Ni bi-MOFs) and composite with an acid functionalized multi-walled carbon nanotubes (Fe-Ni MOF/f-MWCNTs) for electrochemical detection of tartrazine. The as-prepared Fe-Ni MOF/f-MWCNTs was confirmed by the several physicochemical studies. A micro spindle shaped, highly porous, and crystalline Fe-Ni MOF/f-MWCNTs was noticed. The high sensitivity and stability of Fe-Ni MOF/f-MWCNTs/GCE modified electrode was analyzed. Due to its high porosity nature, the analyte molecule effectively gets adsorbed on the modified electrode and undergo electrochemical oxidation effectively. The modified electrode exhibits low limit of detection (LOD) and limit of quantification (LOQ) as 0.04 × 10 -6 mol/L and 0.13 × 10 -6 mol/L towards tartrazine. These results reveal the potential applications of Fe-Ni MOF/f-MWCNTs/GCE as modified electrode material for sensitive detection of tartrazine along with its robust reproducibility, stability, and effective sensing properties., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In this work, a multiplexed colorimetric strategy was initiated for simultaneous and fast visualization of dyes using low-cost and easy-to-prepare indicator papers as sorbents. Response surface methodology (RSM) was employed to model statistically and optimize the process variables for dyes extraction and colorimetric assays. Multiplexed colorimetry was realized by virtue of synchronous color alignments from different dimensions of multiple dyes co-stained colorimetric cards under RSM-optimized conditions, and smartphone-based image analysis was subsequently performed from different modes to double-check the credibility of colorimetric assays. As concept-to-proof trials, simultaneous visualization of dyes in both beverages and simulated dye effluents was experimentally proved with results highly matched to HPLC or spiked amounts at RSM-predicted staining time as short as 50 s ∼3 min, giving LODs as low as 0.97 ± 0.22/0.18 ± 0.08 μg/mL (tartrazine/brilliant blue) for multiplexed colorimetry, which much lower than those obtained by single colorimetry. Since this is the first case to propose such a RSM-guided multiplexed colorimetric concept, it will provide a reference for engineering of other all-in-one devices which can realize synchronous visualization applications within limited experimental steps., Competing Interests: Declaration of Competing Interest The authors declare no competing financial interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

A ternary deep eutectic solvent (DES) consisting of choline chloride, lactic acid, and urea in a molar ratio of 1:2:2 was used to pretreat chamomile residue, followed by carbon dots (CDs) preparation using a one-pot solvothermal method. The CDs prepared under the suitable conditions had a high quantum yield of 47.34% and could be used as a bifunctional fluorescent probe for the detection of tartrazine and Fe(III). The concentration of tartrazine or Fe(III) had a good linear relationship with the fluorescence intensity of CDs that the determination coefficient (R 2 ) was 0.9957 and 0.9943, and the limit of detection (LOD) was 40 nM and 119 nM, respectively. After verifying the different fluorescence quenching mechanisms of CDs by these two substances, a quantitative analysis was performed on real samples with recoveries of 90.70%∼104.29%. Overall, this study provided a promising technology for chemical conversion from low-cost chamomile residue to attractive bifunctional fluorescent probe., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

This work demonstrates the fabrication of a carbon paste electrode containing NiO/CNTs modified with 1-methyl-3-butylimidazolium bromide as the binder (CPE/1-M-3BIBr/NiO/CNTs), and its applications related to the highly sensitive detection of carmoisine. The CPE/1-M-3BIBr/NiO/CNTs system was successfully utilized for the nanomolar determination of carmoisine at pH = 7.0. The CPE/1-M-3BIBr/NiO/CNTs successfully resolved the oxidation signals of carmoisine and tartrazine with a peak separation of 450 mV. This is the first time that an application of an electrochemical sensor for the simultaneous determination of carmoisine and tartrazine, two important azo dyes, has been reported. In addition, wide dynamic linear concentration ranges (70–650 μM for carmoisine and 0.1–750 μM for tartrazine), low detection limits (20 nM for carmoisine and 0.06 μM tartrazine) and excellent reproducibility were reported. The CPE/1-M-3BIBr/NiO/CNTs were successfully used for the analysis of carmoisine and tartrazine in dried fruit and soft drink samples. [ABSTRACT FROM AUTHOR]

Azo dyes, including Tartrazine, Sunset Yellow, and Carmoisine, are added to foods to provide color, but they have no value with regard to nutrition, food preservation, or health benefits. Because of their availability, affordability, stability, and low cost, and because they provide intense coloration to the product without contributing unwanted flavors, the food industry often prefers to use synthetic azo dyes rather than natural colorants. Food dyes have been tested by regulatory agencies responsible for guaranteeing consumer safety. Nevertheless, the safety of these colorants remains controversial; they have been associated with adverse effects, particularly due to the reduction and cleavage of the azo bond. Here, we review the features, classification, regulation, toxicity, and alternatives to the use of azo dyes in food., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

In recent years, artificial additives, especially synthetic food colorants, were found to demonstrate wider properties compared to their natural equivalents; however, their health impact is still not totally mapped. Our study aimed to determine the long-term (30 and 90 days) exposure effect of one of the commonly used artificial food colorants, tartrazine, on NMRI mice. The applied dose of tartrazine referred to the human equivalent dose for acceptable daily intake (ADI). Further, we evaluated its impact on the transcription of a range of epigenetic effectors, members of the DNA methyltransferase ( DNMT ) as well as histone deacetylase ( HDAC) families. Following the exposure, organ biopsies were collected from the lungs, kidneys, liver, and spleen, and the gene expression levels were determined by real-time quantitative reverse transcription PCR (RT-qPCR). Our results demonstrated significant upregulation of genes in the tested organs in various patterns followed by the intake of tartrazine on ADI. Since DNMT and HDAC genes are involved in different steps of carcinogenesis, have roles in the development of neurological disorders and the effect of dose of everyday exposure is rarely studied, further investigation is warranted to study these possible associations.

An electrochemical sensor was designed to identify food colorants in juices. A green polymeric nanocomposite (beta-cyclodextrin/arginine) decorated with gold nanoparticles-capped cysteamine was fabricated on the surface of gold electrodes. Field emission-SEM and energy-dispersive X-ray spectroscopy showed the morphology and the presence of all elements related to all stages of the electrode modification. For three azo dyes (carmoisine, sunset yellow, and tartrazine), the analytical linear range was 10 - 8 to 10 - 4 M, with a low limit of quantification of about 1 nM. The engineered chemosensor showed suitable selectivity for analyzing candidate dyes in the presence of interfering agents. According to the scan rate results, the mass transport was controlled by diffusion, and the reaction on the chemosensor was electrochemically quasi-reversible. The results for different fruit juices confirmed this method's high potential application in detecting artificial color adulteration in food products., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

For food quality control methods, low cost, speed, and simplicity are essential. Electrochemical methods can satisfy all of these requirements. In this paper, we propose a fast and simple voltammetric method using a carbon-paste electrode modified with β-cyclodestrin for the determination of two common food azo dyes: Tartrazine and Carmoisine. To reduce the amount of sample required for analysis, in this work, we explored the prospect of another methodology similar to adsorption stripping voltammetry. The redox behavior of dyes, the influence of pH and scan rate on oxidation currents were investigated. Based on the results the scheme of oxidation of azo dyes was proposed. The use of the proposed approach in combination with the developed sensor makes it possible to determine Tartrazine and Carmoisine within their concentrations of 314-5024 ng/mL and 167-5340 ng/mL with calculation LOD 101 ng/mL and 60 ng/mL respectively. The proposed sensor was tested during analysis of model solutions and soft drinks and showed good results with high reproducibility., (© 2022. The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry.)

Colorant tartrazine is widely used in the food industry, but its long-term and excessive consumption is harmful to human health. Therefore, it is necessary to establish a sensitive detection method for tartrazine. Blue fluorescent carbon dots with L-arginine and o -phenylenediamine as precursors, namely L-Arg/oPD-CDs, were prepared via the hydrothermal method. Then, L-Arg/oPD-CDs were further purified by dialysis, thin layer chromatography and column chromatography. A dual-mode nanosensor based on fluorescent and UV absorption was successfully developed. Excellent linear ranges of 0-5 μM and 10-50 μM were obtained with a low detection limit of 42.3 nM based on fluorescence. A good linear range of 0-50 μM was obtained with a low detection limit of 130.15 nM based on UV absorption. The quenching mechanism of tartrazine towards L-Arg/oPD-CDs fluorescence was the inner filter effect. In addition, a dual-mode nanosensor was used for tartrazine determination in millet, maize flour, carbonated drink, and sugar samples. This study provides new insight into the detection of tartrazine by applying a dual-mode nanosensor.

In this work, sulfur quantum dots (TPA-SQDs) protected by terephthalic acid as a stabilizer were synthesized using a one-pot method. When excited at 310 nm, the synthesized TPA-SQDs solution emitted strong blue fluorescence at 428 nm, and the absolute quantum yield was as high as 85.99%. The proposed SQDs can be used as a fluorescent probe to specifically quench tartrazine (TZ), showing a good linear relationship (R 2  = 0.996) at TZ concentrations of 0.1-20 μM, with a detection limit of 39 nM. By analysing the fluorescence lifetime, UV-Vis absorption spectrum and zeta potential of the assay system, it can be speculated that the fluorescence quenching mechanism of TZ on TPA-SQDs is the inner filter effect (IFE). The proposed method was applied to the detection of TZ in vitamin water and orange juice, and the results were consistent with the determination results by high-performance liquid chromatography. The recoveries and relative standard deviations were 93.2-102.6% and 1.34-2.88%, respectively, which provided an alternative method for the determination of TZ in beverages or other food samples., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Employing dyes in different industrial sectors has produced a serious threat to the environment and living organisms of water bodies and land. For the decontamination of such toxic dyes, efforts have been made to develop an efficient, feasible, and low maintenance processes. In this context, chitosan-zinc selenide (CS-ZnSe) nanoparticles were prepared through chemical reduction method as the efficient photocatalysts for the decontamination of toxic dyes through photocatalysis. Photocatalyst's synthesis was confirmed with the help of FTIR spectroscopy. XRD indicated the hexagonal crystal structure of the CS-ZnSe with a crystallite size of 12 nm. SEM micrographs showed the average nano photocatalyst size as 25 nm. EDX analysis was employed to determine the elemental composition of the CS-ZnSe. An excellent photocatalytic degradation efficiency for tartrazine and sunset yellow dyes was obtained using CS-ZnSe. The results showed a 98% and 97% degradation efficiency for tartrazine dye and sunset yellow (SY) dye at optimized conditions of time (3 h), pH (5), dye concentration (30 ppm), catalyst dosage (0.09 g and 0.01 g) , and at a temperature of 35 °C. Findings of the photocatalytic degradation process fitted well with first-order kinetics for both the dyes. Rate constant, 'K' value was found to be 0.001362 min -1 and 0.001257 min -1 for tartrazine and SY dyes, respectively. While value for (correlation coefficient, R 2 ) was 0.99307 and 0.99277 for tartrazine and sunset yellow dyes, respectively. Recyclability of the photocatalyst was confirmed using it for consecutive cycles to degrade organic dyes. Results showed that the CH-ZnS possesses excellent efficiency in decontaminating organic dyes from industrial wastewater., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The paper describes the development of an electrochemical sensor to be used for the determination of synthetic food colorants such as Sunset Yellow FCF (SY) and Tartrazine (TZ). The sensor is a carbon paper (CP) electrode, manufactured by using hot lamination technology and volume modified with fine-grained graphite powder (GrP). The sensor (GrP/CP) was characterized by scanning electron microscopy, energy dispersive spectrometry, electrochemical impedance analysis, cyclic, linear sweep and differential pulse voltammetry. The mechanism of SY and TZ electrochemical oxidation on GrP/CP was studied. The developed sensor has good electron transfer characteristics and low electron resistance, high sensitivity and selectivity. Applying the differential pulse mode, linear dynamic ranges of 0.005-1.0 μM and 0.02-7.5 μM with limits of detection of 0.78 nM and 8.2 nM for SY and TZ, respectively, were obtained. The sensor was used to detect SY and TZ in non-alcoholic and alcoholic drinks. The results obtained from drink analysis prove good reproducibility (RSD ≤ 0.072) and accuracy (recovery 96-104%).

In this work, an electrochemical sensor for the azo dye compound tartrazine (TRT) determination was proposed. A screen-printed carbon electrode (SPCE) was modified by depositing three-dimensional porous reduced graphene oxide decorated with carbon quantum dots and platinum nanoparticles (Pt/CQDs@rGO/SPCE). The resulting amount of TRT was observed by differential pulse voltammetry. Under optimal conditions, the sensor exhibited two wide linearities ranging from 0.01 to 1.57 μM and 1.57-9.3 μM with the reliability coefficient of determination of 0.991 and 0.992, respectively. The detection limit (LOD) was also estimated to be 7.93 nM. Moreover, the Pt/CQDs@rGO/SPCE suggested high selectivity in the presence of several interfering agents and azo dye compounds that have a similar structure. Additionally, the Pt/CQDs@rGO/SPCE revealed superior recovery values of about 96.5-101.6% for candy, 99.7-103.5% for soft drinks, 96.0-101.2% for jelly powder, and 98.0-103.0% for water samples. Furthermore, the fabricated sensor exhibits excellent selectivity, stability, reproducibility, and repeatability, indicating a great perspective in the monitoring of TRT. Therefore, it can be speculated that the proposed electrode could be effectively applied to determine TRT in food samples., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

A novel nanocomposite film of chitosan/graphene oxide (CHIT/GO)/multi-walled carbon nanotubes (MWCNTs)/gold nanoparticles (AuNPs) was applied to fabricate glassy carbon electrode (CHIT/GO/MWCNTs/AuNPs/GCE) for the determination of Tartrazine (TZ), synthetic dyes in food products. The electrochemical sensors found it to be highly sensitive by combining the signal amplification properties of GO and the excellent electronic and antifouling properties of MWCNTs. The CHIT/GO/MWCNTs/AuNPs/GCE exhibited as superior electron transfer materials and possesses intercalation properties which provide synergistic influence on the increment of the current signals. The optimum conditions were found at pH 7, 30 s, and 0.3 Vs -1 . The modified GCE obtained with a linear response ranging from 10 to 100 mg mL -1 ( r 2 = 0.99037) with a sensitivity of 0.018 μA μM -1 . The limit of detection (LOD) and quantification obtained were 1.45 and 4.83 mg mL -1 , respectively. The determination of TZ in spiked samples was reliable with recovery percentage from 94.52 to 109.0%. The developed sensor successfully tested in the determination of TZ analyte in commercial candy, jelly, and soft drinks with acceptable results.

A fluorescent assay for the selective analysis of tartrazine was developed. Tartrazine is a health-threatening food additive commonly used as fake saffron. An optical nanosensor was fabricated based on molecular imprinting technique in which carbon dots (CDs) as fluorophores and tartrazine as a template molecule were embedded in molecularly imprinted polymer (MIP) matrix. The synthesized CDs embedded in MIP (CDs-MIP) was characterized by various methods. The fluorescence intensity of (CDs-MIP) was selectively quenched in the presence of tartrazine in comparison with other similar food color additives. The correlation between the quenching of CD-MIP and the concentration of tartrazine was used as an optical sensing for rapid detection of tartrazine in the range of 3.3-20.0 nM (1.8-10.7 μg L -1 ) with detection limit of 1.3 nM (0.70 μg L -1 ). Eventually, the designed nanosensor was successfully applied for tartrazine detection in foodstuffs such as fake saffron, saffron tea and saffron ice cream samples., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Based on packed-fiber solid-phase extraction and HPLC-DAD, a simple analytical method for the determination of seven synthetic dyes has been successfully developed. Polystyrene/polypyrrole (PS/PPy) fibers were obtained via electro-spinning of polystyrene skeletal nanofibers, followed by the oxidation with FeCl 3 to trigger the polymerization of pyrrole and the deposition of polypyrrole coatings on PS fibrous skeleton fibers. The relationship between the extraction performance of the fibers and the electrospinning process at different humidities was investigated based on morphologic study and BET surface area. In the extraction process, purification, concentration, and desorption could be accomplished in one step. The established method exhibited good sensitivity, selectivity, reproducibility, and good efficiency for synthetic dyes in casual snacks (preserved fruit, flavored yogurt, and fruity hard candy) samples. With optimal conditions, the LODs (S/N = 3) were 2.4 to 21.09 ng mL -1 , and linearities were acceptable in liquid matrix and solid matrices. The recoveries were 93.9-103.9%., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The current study was designed to develop a single-step and simple approach to effectively fabricate three-dimensional raspberry-like In 3+ /NiO hierarchical nanostructures (In 3+ /NiO RLHNSs) as a modifier, which was subsequently characterized by the techniques of X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and field emission scanning electron microscopy (FE-SEM). The new prepared nano-modifier was practically used to co-detect electrochemically sunset yellow and tartrazine dyes. Potent sensitivity and acceptable selectivity were obtained for the produced In 3+ /NiO RLHNSs to co-detect both the food colorants, thus providing oxidation peaks in differential pulse voltammetry (DPV) with a peak potential separation of ca. 190 mV. The results showed a 5.14-fold and 8.07-fold increase in the electrochemical response of our modified electrode to sunset yellow and tartrazine, respectively, compared to the control (the unmodified electrode). Limits of detection of 2.7 and 3.1 nM were calculated for sunset yellow and tartrazine, respectively. The results from the interaction of common food additives showed satisfactory outcomes for the application of this method in determining sunset yellow and tartrazine in several beverage specimens. Other useful documentation was obtained for the production of portable food additive sensors.

In this paper, using a carbon paste electrode (CPE) modified with 1-ethyl-3-methylimidazolium chloride as an ionic liquid (IL) and NiFe 2 O 4 -rGO nanocomposite (IL/NiFe2O4/rGO/CPE), a sensitive and effective electrochemical sensor is applied to analyze Sunset Yellow. The X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX) and Fourier-transform infrared spectroscopy (FTIR) are employed to characterize the synthesized NiFe 2 O 4 -rGO nanocomposite. The oxidation peak currents of colorants were obtained by CV and DPV techniques; and as a result, the two linear ranges from 0.05 to 30 μM (R 2  = 0.9939) and 30 to 500 μM (R 2  = 0.9953) along with LOD of 0.03 μM for Sunset Yellow is obtained. The proposed sensor is successfully applied to determine the Sunset Yellow, Tartrazine and Allura Red in PBS (pH 3). The IL/NiFe 2 O 4 /rGO/CPE displays a high performance for analysis of these dyes in hair shampoo and an orange juice as real samples with acceptable results., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

In this work, an ultrasensitive sensing system based on fluorescent carbon dots (CDs) was developed for the tartrazine (Tar) determination. The CDs were prepared via a simple one-pot hydrothermal method with m-phenylenediamine as the only precursor. The physical and chemical properties were in detail characterized by transmission electron microscopy (TEM), MALDI-TOF MS, UV-vis absorption and photoluminescence (PL) spectroscopy, elemental analysis, and Fourier transform infrared spectroscopy (FTIR). Upon exposure to Tar, the fluorescence of CDs was efficiently quenched via the dynamic interaction between CDs and Tar as well as the inner filter effect (IFE). With this information, the CDs were proposed as a fluorescence probe for Tar detection. It was found that CDs had high sensitivity and selectivity for Tar sensing, and the linear relationship was observed in the range of 0.01-25.0 μM with the corresponding detection limit (3σ/k) of 12.4 nM, which is much more sensitive than any of the existed CD-based sensing platform. The investigated sensing system was finally utilized for Tar sensing in various food matrices with a high degree of accuracy. The spiked recoveries were in a range of 96.4-105.2%, and the relative standard deviations (RSDs) were lower than 4.13%. This work highlights the great application prospects of CDs for Tar sensing in a rapid, simple, and sensitive way.

This article has introduced and examined a novel and green approach for the very first time, which had been developed for the synthesis of carbon dots (CDs) and performed through the utilization of Elaeagnus angustifolia (E. A) as a natural carbon source. This straightforward procedure has been based upon a hydrothermal treatment with a quantum yield of 16.8% that had been designed to synthesize water-soluble CDs in one step and result in a satisfying fluorescence. Additionally, we have attempted to assess the sensing system that had been exerted through the usage of CDs for the detection of food colorant tartrazine, since they can function as a fluorescent sensor due to the interplay that occurs among tartrazine and CDs leading to the quenching of their fluorescence. The detection limit has been measured to be equaled to 0.086 μM (86 nM) and the linear range has been observed to be 0.47-234 μM. The proposed highly sensitive and simple method has exhibited an excellent selectivity and proved to be effectively applicable for distinguishing the tartrazine of real samples.

Poly(melamine) (PMel) was synthesized via the electropolymerization of melamine monomer, which was then characterized by field-emission scanning electron microscopy (FESEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The possible polymerization mechanisms of melamine were also revealed by FT-IR spectroscopy and UV-Vis spectroscopy. Next, the PMel modified GCE (PMel/GCE) was used for the simultaneous determination of nitrite (NO 2 - ) and tartrazine, and the parameters were optimized. The kinetic study showed that the electrochemical oxidation of nitrite and tartrazine at the surface of PMel/GCE is a typical surface-controlled electrode process. Under the optimun conditions, the developed sensor outperformed those previously reported, and it also exhibited high selectivity and reproducibility. Finally, the PMel/GCE was used for the simultaneous determination of nitrite and tartrazine in foodstuffs, and the results indicated that the proposed sensor could be a promising candidate for accurate determination of nitrite and tartrazine in real food samples., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Herein, we report three-dimensional paper chromatography (3D-PC) as a micro-chromatographic platform. The method was based on applying the origami microfluidic device for separation, coupled by colorimetric methods for simultaneous determination. The microfluidic device fabrication was a facile printing approach. Two azo food dyes, Tartrazine (E102) and Indigo carmine (E132), were selected as a model analyte, while carbonate-bicarbonate buffer was used as the mobile phase. Our micro-chromatographic device is associated with two big advantages including needing very small volume of mobile phase ( ~12 µL) and ultrafast separation time (~35 s). Under the optimal conditions, the method provided acceptable linear ranges of 0. 0 g L 1 -18.0 g L 1 (R 2  = 0.997) for E102 and 0.070 g L 1 -10.0 g L 1 for E132 and the limits of detection (3σ/slope) were evaluated as 0.620 and 0.060 g L 1 , respectively. The proposed method was successfully applied in the separation and quantification of these dyes in commercial food products such as jelly, candy, and four kinds of drink samples without any sample preparation prior to analysis. The mean recovery values for the real sample analysis were in the range of 100.14%-102.38% for E132 and E102 respectively. The inter-device relative standard deviations were in the ranges of 1.5%-11.8%. In total, our chromatographic μPAD is small (1.0 cm × 1.0 cm × 0.5 cm), portable, inexpensive, no need of specialized user, requires low volumes of sample (0.5 μL), and can perform separation using 12 μL of aqueous mobile phase in very short time., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to declare., (Copyright © 2020 Elsevier B.V. All rights reserved.)

A new and rapid dispersive solid phase extraction method by using a green-synthesised UiO-66(Zr)-(COOH) 2 (Zr-BTeC) adsorbent with body-centred cubic (bcu) topology was developed for determination of tartrazine in food samples. Zr-BTeC was used for the first time as an adsorbent for tartrazine. It was synthesised and characterised by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, Brunauer-Emmett-Teller surface area analysis, and zeta potential measurements. Tartrazine was determined at 405 nm spectrophotometrically. Experimental conditions were optimised in order to achieve quantitative recoveries. The sample acidity was found to be 0.02 mol L -1 HCl. The amount of Zr-BTeC was 10 mg. Both adsorption and elution contact times were only 5 s without the need for vortexing. Elution was with 2 mL of 0.5 mol L -1 NH 3 . A sample volume of 45 mL was selected as optimum. The adsorption capacity for tartrazine with Zr-BTeC was found to be 185 mg g -1 and the adsorbent was reusable up to 40 cycles. The tartrazine concentrations found by the developed method in food supplements were compared with the results obtained by HPLC method for the same samples. Statistical analysis results showed that there are insignificant differences between the results of the two methods ( p = .05). The method was successfully applied to the determination of tartrazine in spiked chewing gums, lemon flavoured icing glaze, and jelly samples.

Chemical doping with heteroatoms was employed to prepare N,Cl co-doped fluorescent carbon dots (N,Cl-FCDs) which may be designed for the detection of tartrazine. Using urea as the N source and FeCl 3  · 6H 2 O as the Cl source, N,Cl-FCDs were synthesized by hydrothermal method with carbon dots prepared from aloe. Compared with pure carbon dots (CDs), N,Cl-FCDs resulted in dramatic improvement in the fluorescence properties and surface physical chemical properties. The fluorescence quantum yield of the N,Cl-FCDs was as high as 60.52%. As an effective fluorescence probe for tartrazine, a good linear relationship between N,Cl-FCDs and tartrazine was constructed at the concentration range from 0.1 to 30 μM with a detection limit of 48 nM based on the mechanism of fluorescence resonance energy transfer (FRET). The proposed fluorescent probe method was successfully applied to detect tartrazine in beverages, which is expected to have a potential application in the field of food analysis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

This study aimed to synthesize Bi 2 Fe 4 O 9 and apply it to the degradation of tartrazine yellow dye. Bi 2 Fe 4 O 9 was synthesized using the solid-state reaction and the Pechini method. The materials obtained were characterized using X-ray diffraction (XRD), visible ultraviolet spectroscopy (UV-Vis) and field emission scanning electron microscopy (FEG). The microscopic images revealed a morphological difference between the two materials in which the material obtained by the Pechini method is the most porous and have the largest surface area. The pellet obtained by the Pechini method was seen to have a lower bandgap value when compared with the sample solid state reaction. In the photocatalysis tests, the best performance was also that of the material obtained by the Pechini method, with 99.34% degradation, while the material obtained by solid state reaction showed 85.86% in 120 minutes. The solution degraded with the material obtained by the Pechini method presented 81.66% of mineralization while the solution with the material obtained by solid state reaction showed 60.97% of mineralization. The results confirmed that the material obtained by both syntheses is able to maintain its effectiveness after 10 repetitions of the photocatalytic process, proving to be promising for waste treatment in the industrial field.

In the work, water-soluble bovine serum albumin-protected fluorescent nickel nanoclusters (BSA-NiNCs) are used as fluorescent probes to construct a label-free fluorescence quenching sensor for sensitive and selective detection of tartrazine. The fluorescent BSA-NiNCs are synthesized in one pot using BSA as both the template and reducing agent, and hydrogen peroxide as the additive. The as-prepared NiNCs are characterized by using various analytical techniques like transmission electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, UV-Vis absorption spectroscopy, circular dichroism spectroscopy, and fluorescence spectroscopy. The synthesized BSA-NiNCs have a quantum yield of ca. 8% by using quinine sulfate as a standard. The sensor for tartrazine detection shows a wide linear range of 0.01-3.5 μM, with a low detection limit of 4 nM. The fluorescence quenching very likely results from the combination of the intermolecular interactions and the secondary inner filter effect between BSA-NiNCs and tartrazine. Then, the proposed sensor is successfully employed for tartrazine detection in drink samples, and the results are comparable with those based on a reference HPLC method., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Pigments are still widely used in food and feed industry and their resides in food might be harmful to human health due to their side effects. A high performance liquid chromatography (HPLC) method for simultaneous determination of pigments including tartrazine, lutein, capsanthin, canthaxanthin and β-carotene in animal-derived foods (including the muscle and liver of swine, the muscle, liver and skin of chicken and duck, and the muscle of fish) and feeds (swine, chicken and duck) was developed. Lutein, capsanthin, canthaxanthin and β-carotene were extracted with acetonitrile-ethyl acetate by ultrasonication, and tartrazine was extracted with water, followed by defatting with n-hexane and clean-up by solid phase extraction on weak anion exchange cartridges. The quantitation of the five pigments was performed by HPLC with ultraviolet and visible spectrophotometer detection. Chromatographic separations were performed on a C8 column with gradient elution. The mean recoveries of analytes ranged from 80.4 to 92.5%. The intra- and the inter-day variabilities were below 15.0%. This HPLC method was suitable for the routine determination of pigment residues in animal-derived foods and feeds., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The current study performed simultaneous identification of semisynthetic chlorophyllin (Cu-Chl) and synthetic food colorants in food matrices. The quantitative assessment of these synthetic and semisynthetic colorants was determined by using analytical method based on reverse-phase high-performance liquid chromatography (RP-HPLC) equipped with UV-visible detection. The concentration of Cu-Chl in hard candy was 3.334 mg/kg and 4.489 mg/kg in the soft candy, while contents of other colorants i.e. Tartrazine and Brilliant Blue were within 4.74-140.284 mg/kg. The extraction of Cu-Chl and synthetic colorants from different food matrixes was performed with a recovery range of 90-97% and RSD of 1-9%. Overall, the current developed RP-HPLC method could detect both green coloured synthetic and semisynthetic food colorants by a single run and could be used for monitoring different colorants in other complex matrices. This is the first report in India to determine Cu-Chl in foodstuffs and beverages by using RP-HPLC with UV-vis detector., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

We used thiamine nitrate (TN) as single material to fabricate nitrogen and sulfur co-doped carbon quantum dots (N,S-CQDs) with a quantum yield of 10.4% through one-pot hydrothermal method, and its properties were characterized by TEM, XPS, FTIR, fluorescence (FL) and UV-vis spectrophotometer, respectively. The fluorescence of N,S-CQDs was effectively quenched in the presence of vitamin B12 (VB12)/tartrazine due to Förster resonance energy transfer (FRET). Moreover, the rate (K T ) and efficiency (E%) of energy transfer from N,S-CQDs (as a donor) to VB12/tartrazine (as an acceptor) enhanced with increasing the concentrations of acceptor, and the K T and E% were also varied with the change of excitation wavelengths (from 338 to 408 nm). Based on this principle, a multifunctional fluorescence probe was designed for selective and sensitive detection of VB12/tartrazine with a detection limit (3σ/slope) of 15.6/18.0 nmol/L. Meanwhile, the proposed method was successfully employed to detect VB12/tartrazine in milk and several beverages with a recovery range of 97.5-104.2%/91.0-110.6%., (Copyright © 2018. Published by Elsevier B.V.)

The use of pesticides in horticultural sector in Niger has become an integral part of modern agriculture. Nevertheless, their inappropriate use can generate negative health effects to operators. A study was carried out among Kongou farmers in order to assess their potential dermal exposure (PDE). The UK-POEM model was used to quantify the PDE during mixing/loading and application according to the local practices. In order to determine which parts of the operator body are subject to most contamination during spraying and to validate the theoretical model used, a patch method was used with a tartrazine dye. The deposits of the tartrazine on patches were measured by colorimetry thanks to the absorbance value determined after their extraction in water and a calibration curve. A total of ten spraying trials (five trials with the hand-held sprayer and five others with the backpack sprayer) were performed by different producers at 0.5 and 1 m height for each trial. The survey shows that 92% of the farmers are illiterate and the most common active substances identified are organophosphate or pyrethroids insecticides. Seventy percent of operators do not use any personal protective equipment (PPE) during mixing/loading or spraying. The predictive systemic exposure levels vary from 0.0027 mg kg -1  bw per day to 0.7692 mg kg -1  bw per day for backpack sprayer and from 0.0261 mg kg -1  bw per day to 0.9788 mg kg -1  bw per day for hand-held sprayer, several times higher the Acceptable Operator Exposure Level (AOEL) for some actives substances. Theoretical modeling indicates more exposure of operator by a hand-held sprayer than a backpack sprayer. The patch method results show that the deposits of dye increase when the position of sprayer nozzle increases from 0.5 to 1 m for the two sprayers. All parts of the operator body are contaminated but lower body parts and chest are the most exposed. The patch method results also show that hand spraying contaminates operator more than backpack spraying, confirming the results of the theoretical model.

In this research, a facile synthesis route was used for preparation of cobalt ferrite@SiO 2 @polyethyleneimine magnetic nanoparticles (Co-Fe 2 O 4 @PEI) as a new sorbent in the service of ultrasound assisted dispersive micro-solid phase extraction (UA-DMSPME) for influential clean-up, preconcentration, and determination of tartrazine (TA) prior to UV-Vis spectrophotometric detection. The understudy sorbent was fully characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Energy dispersive X-ray analysis (EDX), and vibrating sample magnetometer (VSM). Different operating parameters which affected the extraction efficiency of TA viz. sorbent dosage, extraction time, pH, and volume of eluent were investigated and optimized by using central composite design (CCD). Under optimal conditions, the enrichment and preconcentration factor, limit of detection (LOD), quantification (LOQ), and precision were obtained 98.01, 66.67, 5.09, and 16.96 ng mL -1 , and <5.5% respectively. Good linear response (20-4000 ng mL -1 ) over the tested concentration range was achieved with the value of R 2  = 0.9977. Satisfactory recoveries (>99.5%) of TA in complicated samples including saffron spray, cotton candy and water samples were achieved. This superior validation implies high applicability of the purposed method in terms of it being simple, fast, effective, and accessible: all of these allow for accurate analysis at the trace level., (Copyright © 2018. Published by Elsevier Inc.)

Color additives are used widely by the food industry to confer a desirable appearance. Some of the most used colorants (Tartrazine (E102), Sunset Yellow (E110), Red Allure (E129) and Blue Brilliant (E133)) were determined in this study using microemulsion electrokinetic capillary chromatography (MEEKC). Regression coefficients were greater than 0.9981; intra- and inter-day precisions, in terms of percentage RSD, were less than 7.01% and 8.55%, respectively; recoveries were between 90 and 100% in most cases. LODs and LOQs ranged from 0.24 to 1.21 mg L -1 and from 0.80 to 4.03 mg L -1 , respectively. Moreover, MEEKC consumed less solvent than HPLC, making the analysis more environmentally friendly. The proposed method is suitable for the determination of colorants in a wide variety of foods. Results showed that consumers should be aware of colorants to avoid consumption exceeding recommended amounts., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

A method based on digital image is described to quantify tartrazine (E102), yellow, and allura red (E129) colorants in food samples. HPLC is the habitual method of reference used for colorant separation and quantification, but it is expensive, time-consuming and it uses solvents, sometimes toxic. By a flatbed scanner, which can be found in most laboratories, images of mixtures of colorants can be taken in microtitration plates. Only 400 µL of sample are necessary and up to 92 samples can be measured together in the same image acquisition. A simple-to-obtain color fingerprint is obtained by converting the original RGB image into other color spaces and individual PLS models are built for each colorant. In this study, root mean square errors of 3.3 and 3.0 for tartrazine and 1.1 and 1.2 for allura red have been obtained for cross-validation and external validation respectively. Results for repeatability and reproducibility are under 12%. These results are slightly worse but comparable to the ones obtained by HPLC. The applicability of both methodologies to real food samples has proven to give the same result, even in the presence of a high concentration of an interfering species, provided that this interference is included in the image analysis calibration model. Considering the colorant content found in most samples this should not be a problem though and, in consequence, the method could be extended to different food products. Values of LODs of 1.8 mg L -1 and 0.6 mg L -1 for tartrazine and allura red have been obtained by image analysis., (Copyright © 2018 Elsevier B.V. All rights reserved.)

In this work, a simple, rapid, sensitive, selective spectrofluorimetric method was applied to detect tartrazine. The fluorescence of acriflavine could be efficiently quenched by tartrazine. The method manifested real time response as well as presented satisfied linear relationship to tartrazine. The linear response range of tartrazine (R 2 = 0.9995) was from 0.056 to 5 μmol L -1 . The detection limit (3σ/k) was 0.017 μmol L -1 , indicating that this method could be applied to detect traces of tartrazine. The accuracy and precision of the method was further assured by recovery studies via a standard addition method, with percentage recoveries in the range of 96.0% to 103.0%. Moreover, a quenching mechanism was investigated systematically by the linear plots at varying temperatures based on the Stern-Volmer equation, fluorescence lifetime and UV-visible absorption spectra, all of which proved to be static quenching. This sensitive, selective assay possessed a great application prospect for the food industry owing to its simplicity and rapidity for the detection of tartrazine., (Copyright © 2017 John Wiley & Sons, Ltd.)

Objectives: The aim of this study was to examine the occurrence of five azo food dyes-tartrazine, sunset yellow, carmoisine, allura red, and ponceau 4 R-in the food supply chain of Singapore and their effects on the in vitro synthesis of leukotriene B 4 (LTB 4 ) and F 2 -isoprostanes., Methods: Trained personnel recorded the names of foods and beverages sold in a local supermarket that contained at least one of the five azo dyes. The occurrence of the azo dyes in the local food supply was computed. The synthesis of LTB 4 and F 2 -isoprostanes from freshly isolated blood neutrophils were measured using gas chromatography-mass spectrometry., Results: Of the 1681 processed food items, 194 (11.54%) contained at least one of the five azo dyes. Tartrazine was most prevalent in food and beverage products sold in Singapore, followed by allura red, sunset yellow, ponceau 4 R, and carmoisine. The five azo dyes augmented the in vitro synthesis of LTB 4 and F 2 -isoprostanes from blood neutrophils. Tartrazine was significantly more potent in increasing LTB 4 synthesis than the other dyes, which exhibited similar potencies. The five food dyes increased the formation of F 2 -isoprostanes from blood neutrophils at all tested concentrations., Conclusion: The high prevalence of azo dyes in the food supply of Singapore and their ability to elicit proinflammatory responses in vitro suggest a potential health risk to the local population., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Citrus sinensis and Citrus limon peels were used to synthesize two different kinds of carbon quantum dots (CQDs) via an unsophisticated and inexpensive carbonization procedure. The proposed synthesis is straightforward and adheres to the principles of green chemistry since no organic solvents are used and no toxic by-products are formed, while the residual resources employed facilitate the large scale synthesis of dots. The Citrus sinensis and Citrus limon peels are proved to be excellent precursors for the synthesis of CQDs with highly practical applications. The CQDs display strong excitation-independent, blue fluorescence, which is stable over time. Splendid water dispersibility, photostability and stability over a wide range of pH are some of the main advantages of the CQDs, which enable them to be used as a fluorescent probes. Although many of their features are alike, our findings demonstrate that each kind of the CQDs lend itself to quite distinct analytical applications. The developed fluorescent probes possess high potential for sensitive and selective detection of Fe 3+ (Citrus sinensis CQDs) and tartrazine (Citrus limon CQDs) via a quenching mechanism. The decrease in fluorescence intensity is in linear relationship with the concentrations of Fe 3+ and tartrazine in the ranges of 0.01-1.0μM and 0.6-23.5μΜ, respectively. Moreover, their low cytotoxicity reinforces their applicability towards cell bioimaging and intracellular detection of Fe 3+ , which were further studied., (Copyright © 2017 Elsevier B.V. All rights reserved.)

A new nanocomposite (ZnO/Cysteic acid) was deposited on glassy carbon electrode by cyclic voltammetry. Uniform deposition of the nanocomposite was observed by scanning electron microscopy. The electron transfer characteristics of two food additives, sunset yellow and tartrazine, were greatly improved on the modified electrode. The prepared electrode was used in the sensitive simultaneous determination of sunset yellow and tartrazine by differential pulse voltammetry. Linear calibration curves were obtained in the concentration ranges of 0.1-3.0, and 0.07-1.86μM, and detection limits of 0.03 and 0.01μM for sunset yellow and tartrazine, respectively. The proposed method was evaluated by determination of the dyes in processed soft drinks with satisfactory results (recovery>95% and RSD%<5%)., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Tartrazine is an azo food dye, which is orange-colored and water soluble. It is usually used in foods, pharmaceuticals, cosmetics, and textiles. Tartrazine has the potential to cause an adverse health effect on humans, such as hyperactivity in children, allergy, and asthma. Joint FAO/WHO Expert Committee on Food Additive and EU Scientific Committee for Food have standardized the acceptable daily intake for tartrazine that is 7.5 mg kg -1 body weight. Many researchers have detected the presence of tartrazine for monitoring the quality and safety of food products. In this review paper, we highlighted various tartrazine detection and extraction methods. Some of the analytical methods are available such as high-performance liquid chromatography, electrochemical sensor, thin-layer chromatography, spectrophotometry, capillary electrophoresis, and liquid chromatography-tandem mass spectrometry. Also, we discuss following extraction steps: liquid-liquid extraction, solid-phase extraction, membrane filtration, cloud point extraction, and other extraction method. In addition, a brief overview is presented explaining the synthesis process and metabolism of tartrazine and the maximum permitted level in different countries. This review paper will give an insight into different extraction and analytical methods for the determination of tartrazine in healthy foods, which will attract the attention of public toward food safety and quality, and also the interest of food industry and government bodies.

An ultraviolet visible (UV-Vis) spectrophotometric and partial least squares (PLS) chemometric method was developed for the simultaneous determination of erythrosine B (red), Brilliant Blue, and tartrazine (yellow) dyes. A training set (n = 64) was generated using a full factorial design and its accuracy was tested in a test set (n = 13) using a Box-Behnken design. The test set garnered a root mean square error (RMSE) of 1.79 × 10 -7 for blue, 4.59 × 10 -7 for red, and 1.13 × 10 -6 for yellow dyes. The relatively small RMSE suggests only a small difference between predicted versus measured concentrations, demonstrating the accuracy of our model. The relative error of prediction (REP) for the test set were 11.73%, 19.52%, 19.38%, for blue, red, and yellow dyes, respectively. A comparable overlay between the actual candy samples and their replicated synthetic spectra were also obtained indicating the model as a potentially accurate method for determining concentrations of dyes in food samples.

A sorption-spectrometric method for determination of the anionic synthetic dyes based on their sorption on silica sorbent modified with hexadecyl groups (C16) followed by measuring the diffuse reflectance spectra on the surface of the sorbent has been proposed. Adsorption of sulfonated azo dyes Tartrazine (E102), Sunset Yellow FCF (E110), Ponceau 4R (E124) reaches maximum in acidic medium (1M HCl - pH 1). For the quinophthalone type dye Quinoline Yellow (E104), the adsorption is also maximal in an acidic medium (1M HCl - pH 2). The triphenylmethane dye Fast Green FCF (E143) is absorbed in the wider area of pH (1M HCl - pH 6). Increasing concentration of the dyes in a solution led to the increase in absorption band intensity in diffuse reflectance spectra of the adsorbent, which was used for their direct determination. The proposed method was applied to the determination of dyes in beverages and pharmaceuticals., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Four common food colorants, containing tartrazine, sunset yellow, ponceau 4R and methyl orange, are simultaneously quantified without prior chemical separation. In this study, an effective artificial neural network (ANN) method is designed for modeling multicomponent absorbance data with the presence of shifts or changes of peak shapes in spectroscopic analysis. Gradient descent methods such as Levenberg-Marquardt function are usually used to determine the parameters of ANN. However, these methods may provide inappropriate parameters. In this paper, we propose combination of genetic algorithms (GA) and partial swarm optimization (PSO) to optimize parameters of ANN, and then the algorithm is used to process the relationship between the absorbance data and the concentration of analytes. The hybrid algorithm has the benefits of both PSO and GA techniques. The performance of this algorithm is compared to the performance of PSO-ANN, PC-ANN and ANN based Levenberg-Marquardt function. The obtained results revealed that the designed model can accurately determine colorant concentrations in real and synthetic samples. According to the observations, it is clear that the proposed hybrid method is a powerful tool to estimate the concentration of food colorants with a high degree of overlap using nonlinear artificial neural network., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Two yellow dyes, together with tartrazine (Y4), were found in cucumbers pickled in soy sauce, for which the use of tartrazine is permitted, by TLC, LC-DAD, and LC-MS. The retention times on LC chromatograms and the maximum absorbance wavelengths measured by LC-DAD of the two dyes were different from those of tartrazine. Mass spectra of the dyes indicated that these dyes lacked one sulfonyl group of tartrazine. The presence of two less sulfonated dyes in tartrazine has been reported. Hence, the two less sulfonated dyes were synthesized. The two dyes found in cucumbers were compared with the synthesized dyes by LC-DAD and LC-MS. Since the retention times of the dyes in cucumbers on the LC chromatograms, as well as their LC-DAD spectra and mass spectra, were found to be identical with those of the synthesized dyes, we concluded these dyes are the less sulfonated subsidiary dyes of tartrazine.

In this study, a new absorbent based on cellulose nanosponges modified with methyltrioctylammonium chloride (aliquat 336) was prepared and used for pre-concentration, removal and determination of tartrazine dye, using UV-vis spectrophotometry. This adsorbent was fully characterized using various instrumental techniques such as SEM, FTIR and XRD spectra. The pre-concentration and removal procedures were studied in column and batch modes, respectively. The effects of parameters such as pH of the aqueous medium, methyltrioctylammounium chloride dose, adsorbent amount, desorbing conditions and interfering ions on the adsorption of tartrazine were investigated and optimized. The fitting experimental data with conventional isotherm models revealed that the adsorption followed the Brunauer-Emmett-Teller (BET) model and the maximum adsorption capacity for tartrazine was 180mg/g with modified nanosponges. Under the optimized conditions, the calibration curve was linear over the range of 2-300ng/mL and the limit of detection was 0.15ng/mL. The relative standard deviation (RSD) for 20 and 100ng/mL of tartrazine were 3.1% and 1.5%, respectively. The proposed method was applied for pre-concentration and determination of tartrazine dye in different water samples., (Copyright © 2016 Elsevier Inc. All rights reserved.)

A simple and highly sensitive electrochemical sensor based on an electrochemically reduced graphene oxide-modified screen-printed carbon electrode (ERGO-SPCE) for the simultaneous determination of sunset yellow (SY) and tartrazine (TZ) was proposed. An ERGO film was coated onto the electrode surface using a cyclic voltammetric method and then characterized by scanning electron microscopy (SEM). In 0.1M phosphate buffer at a pH of 6, the two oxidation peaks of SY and TZ appeared separately at 0.41 and 0.70V, respectively. Surprisingly, the electrochemical response remarkably increased approximately 90- and 20-fold for SY and TZ, respectively, using the modified electrode in comparison to the unmodified electrode. The calibration curves exhibited linear ranges from 0.01 to 20.0µM for SY and from 0.02 to 20.0µM for TZ. The limits of detection were found to be 0.50 and 4.50nM (at S/N=3) for SY and TZ, respectively. Furthermore, this detection platform provided very high selectivity for the measurement of both colorants. This electrochemical sensor was successfully applied to determine the amount of SY and TZ in commercial beverages. Comparison of the results obtained from this proposed method to those obtained by an in-house standard technique proved that this developed method has good agreement in terms of accuracy for practical applications. This sensor offers an inexpensive, rapid and sensitive determination. The proposed system is therefore suitable for routine analysis and should be an alternative method for the analysis of food colorants., (Copyright © 2016 Elsevier B.V. All rights reserved.)

In the present study, for the first time electromembrane extraction followed by high-performance liquid chromatography coupled with ultraviolet detection was developed and validated for the determination of tartrazine in some food samples. The parameters influencing electromembrane extraction were evaluated and optimized. The membrane consists of 1-octanol immobilized in the pores of a hollow fiber. As a driving force, a 30 V electrical field was applied to make the analyte migrate from sample solution with pH 3, through the supported liquid membrane into an acceptor solution with pH 10. Best preconcentration (enrichment factor >21) was obtained in extraction duration of 15 min. Effects of some solid nano-sorbents like carbon nanotubes and molecularly imprinted polymers on membrane performance and electromembrane extraction efficiency were evaluated. The method provided the linearity in the range 25-1000 ng/mL for tartrazine (R(2) > 0.9996) with repeatability range (RSD) between 3.8 and 8.5% (n = 3). The limits of detection and quantitation were 7.5 and 25 ng/mL, respectively. Finally, the method was applied to the determination and quantification of tartrazine from some food samples with relative recoveries in the range between 90 and 98%., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Beer is one of the most popular alcoholic beverages worldwide. For consumer acceptance, significant factors are its taste, flavour and colour. This study determines selected synthetic green, blue and yellow food colorants in popular Easter herb-coloured green beers on tap produced in breweries on Holy Thursday. The abuse of beer colouring with Tartrazine (E 102), Quinoline yellow (E 104), Sunset yellow (E 110), Patent blue (E 131), Indigo carmine (E 132), Brilliant blue FCF (E 133), Green S (E 142) and Fast green FCF (E 143) was assessed in 11 green beer samples purchased in local restaurants. HPLC was used for the separation and detection of artificial colorants with diode-array detection and a Chromolith Performance CN 100 × 4.6 mm column with guard pre-column Chromolith CN 5 × 4.6 mm. Separation was performed in gradient elution with mobile phase containing methanol-aqueous 2% ammonium acetate at pH 7.0. The study showed that eight beers (70%) marketed in the Czech Republic contained artificial colorants (Tartrazine and Brilliant blue FCF). The concentration of colorants found in analysed green herb-coloured beers ranged from 1.58 to 3.49 mg l(-)(1) for Tartrazine, 0.45-2.18 mg l(-)(1) for Brilliant blue, while Indigo carmine was detected only once at concentration 2.36 mg l(-)(1). Only three beers showed no addition of the synthetic colorants. However, the levels of artificial colorants found in beers marketed in the Czech region were very low and did not show a serious risk for consumers' health.

A novel electrochemical platform was designed for the simultaneous determination of Sunset Yellow (SY) and Tartrazine (TT), synthetic food dyes, by combining the signal amplification properties of graphene oxide (GO) and the excellent electronic and antifouling properties of multi-walled carbon nanotubes (MWCNTs). Stable dispersion of GO/MWCNTs composite was produced by sonication mixing. Compared with glassy carbon, MWCNTs and GO electrodes, GO/MWCNTs electrode exhibited strong enhancement effect and greatly increased the oxidation signal of SY and TT. Under optimized conditions, the enhanced anodic peak currents represented the excellent analytical performance of simultaneous detection of SY and TT in the range of 0.09-8.0 μM, with a low limit of detection of 0.025 μM for SY and 0.01 μM for TT (S/N = 3), respectively. To further validate its possible application, the proposed method was successfully used for the determination of SY and TT in orange juice with satisfactory results., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Well-defined quality control (QC) processes are used to determine whether a certain procedure or action conforms to a widely accepted standard and/or set of guidelines, and are important components of any laboratory quality assurance program (Popa-Burke et al., J Biomol Screen 14: 1017-1030, 2009). In this chapter, we describe QC procedures useful for monitoring the accuracy and precision of laboratory instrumentation, most notably automated liquid dispensers. Two techniques, gravimetric QC and photometric QC, are highlighted in this chapter. When used together, these simple techniques provide a robust process for evaluating liquid handler accuracy and precision, and critically underpin high-quality research programs.