Melamine sponges incorporated azo-linked porous organic polymer as adsorbent for extraction and determination of six B vitamins using pipette tip micro solid-phase extraction.

A novel azo-linked porous organic polymer (AL-POP) was synthesized from caffeic acid and benzidine via an azo-coupling reaction and characterized by FTIR, SEM-EDS, BET, TGA, XRD and zeta potential analysis. AL-POPs were incorporated into melamine sponges and used for pipette tip micro solid-phase extraction (PT-MSPE) of six types of B vitamins (including thiamine, riboflavin, nicotinamide, pyridoxine, folic acid, and cyanocobalamin). After extraction, the samples were analyzed using high performance liquid chromatography-diode array detection (HPLC-DAD) system. The effect of AL-POP composition on the extraction efficiency (EE) of vitamins was investigated and benzidine to caffeic acid mol ratio of 1.5, 3.35 mmol of NaNO2, and reaction time of 8 h were selected as optimum conditions. The efficiency of the extraction process was improved by optimizing various parameters such as the amount of sorbent, pH and ionic strength of the sample, sample volume, number of sorption and desorption cycles, type of wash solvent, and type and volume of eluent solvent. Linearity (R2≥0.9987), Limit of detection (LOD) (11.88-18.97 ng/mL), limit of quantification (LOQ) (39.62-63.23 ng/mL), and enrichment factor (EF) (1.27-4.31) were obtained using calibration curves plotted under optimum conditions. Recovery values of these six B vitamins in the spiked multivitamin syrup samples varied from 80.01% to 108.35%, with a relative standard deviation (RSD) below 5.44%. Eventually, the optimized method was successfully used to extract and quantify the B vitamins in multivitamin syrup and non-alcoholic beer.

An indicator color chart for quick detection of Pigment Red 53 in cosmetic products in Indonesia.

BACKGROUND: Pigment Red 53 is a dangerous synthetic dye that is often added to cosmetics, even though its use in cosmetic products has been prohibited because of possible impacts on health. Faster and more sensitive detection of Pigment Red 53 is needed for onsite analysis to protect the community from illegal cosmetics that contain the dye. Indicator color charts are a kind of analytical method that can be used to detect Pigment Red 53 in cosmetic products, including lipstick, rouge, and eyeshadow. Such charts are practical, fast, and can be used for onsite analysis. METHODS: In this study, an indicator for Pigment Red 53 detection was obtained through a reagent reaction that caused a specific color change. An indicator color chart was then produced by setting out in paper form the series of colors which resulted from the reaction of specific chemical reagents and Pigment Red 53 solutions at concentrations of 10, 20, 40, 60, 80, and 100 ppm. RESULTS: The testing results showed that the indicator color chart may be used as an initial screening method for the detection of Pigment Red 53 in cosmetic products with a detectable minimum concentration of 10 ppm. Out of nine samples, only one (Eyeshadow 3) tested positive for Pigment Red 53. Further analysis was carried out on the indicator color chart and the results showed good agreement with TLC and UV-Vis spectrophotometry methods. CONCLUSION: The results reported in this paper demonstrate that the indicator color chart is a good prospective method for onsite analysis to detect Pigment Red 53 in cosmetic samples, with a lower detection limit compared to polymer-based indicators.

Eco-Friendly Simultaneous Estimation of Ponceau 4R and Carmoisine Employing an Analytical Quality by Design-Aided RP-HPLC Method in Commercial Food Samples Utilizing a Green Ultrasound-Assisted Extraction Technique.

BACKGROUND: Ponceau 4R (E124) and carmoisine (CMS; E122) are frequently utilized azo synthetic dyes in the food industry owing to their aesthetically pleasing coloration and broad consumer acceptability. It is imperative to prioritize environmentally favorable technologies for quantifying these dyes, as excessive consumption of these poses significant health risks. OBJECTIVE: The primary objective of this research was to establish a reversed-phase (RP)-HPLC method that could simultaneously detect Ponceau 4R and CMS, implementing green analytical chemistry (GAC) and analytical quality by design (AQbD), using an ultrasound-assisted extraction (UAE) technique in commercial food samples. METHODS: An Agilent Eclipse Plus column (C18, 250 × 4.6 mm id, 5 µm) was utilized for effective separation with a mobile phase of ethanol-acetate buffer pH 5 (60:40, v/v), flow rate of 1 mL/min, and detection wavelength of 515 nm. Critical variables selected for method optimization were ethanol percentage and flow rate, determined using central composite design (CCD). In order to adhere to the 12 principles of green chemistry, hazardous solvents were substituted with ethanol, which is distinguished by its ease of use, effectiveness, and ecological sustainability. The greenness assessment was conducted utilizing the green analytical procedure index (GAPI), analytical eco-scale (AES), and analytical greenness metrics (AGREE). RESULTS: The respective retention times for Ponceau 4R and CMS were 2.276 and 3.450 min. The recovery rate of Ponceau 4R and CMS fluctuated between 70% and 102% and 80% and 102%, respectively, across various marketed food samples. The procedure passed validation in accordance with the International Conference on Harmonization Q14 guidelines. CONCLUSION: The devised method demonstrates that the validation parameters like linearity, precision, sensitivity, and reproducibility are within the specified limits of ICH guidelines. The greenness assesment tools GAPI, AES, and AGREE produced the most favorable results. HIGHLIGHTS: In future, environmentally sustainable, solvent-based, robust AQbD methodologies for assessing varieties of food colorants may be adopted and improved commercially.

Development of a novel bionanocomposite of UiO-66/xanthan gum/alginate crosslinked by calcium chloride for azo dye removal: Insight into adsorption kinetics, isotherms, and thermodynamics.

In the present work, UiO-66/xanthan gum/alginate bionanocomposite adsorbent was fabricated using the in-situ crosslinking-gelation method, characterized by different techniques, and finally used for the removal of methylene blue dye from aqueous solution. Adsorption studies were performed using batch experiments and the influencing operational parameters such as contact time, initial pH solution, temperature, initial dye concentration, adsorbent dose, pHPZC, swelling, regeneration, and reuse of the adsorbent were investigated. The various kinetic models (pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion) and isotherm models (Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich) were used to analysis of the experiment results. The results were best fitted to the pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity of dye on the adsorbent was obtained at 9.96 mg/g at pH = 11. The value of pHPZC for the adsorbent was obtained at about 8. According to thermodynamic parameters, the dye adsorption was found as spontaneous and endothermic due to the negative value of the ΔG° and ΔH°. After 4 times of reusability cycles, the adsorption efficiency remained above 86 %, which represented a certain regeneration ability. As a result, this research indicates that UiO-66/xanthan gum/alginate bionanocomposite can be utilized as a promising bio-adsorbent for azo dye removal from contaminated wastewater.

GC-MS Analysis of Primary Aromatic Amines Originated From Azo Dyes in Commercial Textile or Leather Products Using Helium Alternative Carrier Gases.

BACKGROUND: In recent years, due to the global shortage of helium gas, the development of gas chromatography (GC) analytical methods using alternatives to helium carrier gases is necessary. OBJECTIVE: The objective of this study was to examine the applicability of hydrogen and nitrogen as alternative carrier gases using the test method for azo compounds in the Act on Control of Household Products Containing Harmful Substances of Japan. METHOD: The gas chromatograph mass spectrometer (GC-MS) analytical method using hydrogen and nitrogen as alternative carrier gases was compared with a method using helium for 26 primary aromatic amines (PAAs) originated from azo dyes. RESULTS: When hydrogen and nitrogen were used as carrier gases under the same conditions used during analysis using helium (same column, gas flow rate, oven temperature conditions, etc.), sufficient peak separation of 26 PAAs was obtained. The sensitivities of the methods using helium and hydrogen were comparable, whereas the sensitivity was lower when nitrogen was used, with the detection limits ranging from 1/220 to 1/25. However, all carrier gases achieved quantification at concentrations below the standard value (30 µg/g) of the Act on Control of Household Products Containing Harmful Substances, and the results were in agreement with the standard value for the target product. CONCLUSIONS: Our results indicated that hydrogen or nitrogen can be used as alternative carrier gases to helium for GC-MS analysis of azo compounds producing specific aromatic amines. HIGHLIGHTS: Using hydrogen or nitrogen as an alternative carrier gas to helium, azo compounds could be quantified with excellent accuracy.

Smartphone-based procedure to determine content of single synthetic dyes in food using the Arata-Possetto extraction method.

The use of additives, including dyes, is common in the preparation of food products. The analytical control of artificial food dye content is relevant since some, such as azo dyes, may produce cancer and attention deficit disorders and hyperactivity in children. Consequently, the maximum permitted concentration of azo dyes in food is regulated by current legislation. Therefore, it is of interest to find simple and fast procedures for the control of these compounds. The aim of this study is to determine the concentration of azo dyes in food samples by the Arata-Possetto method - based on the extraction of azo dyes employing natural wool -, followed by the analysis of an image captured by a smartphone camera. After experimentally determining the optimal extraction conditions, the calibration curves for standard solutions of different food dyes and the color of the dyed wool were obtained. Results from dyed wool image processing were compared with the absorbance spectra of the solutions before extraction as measured by a diode array spectrophotometer. The spectrophotometric and the image processing procedures were employed to obtain the calibration curves for different food dyes, which were subsequently employed to analyze food samples. Statistical treatment shows that the results of both methods are comparable.

Characterizing azobenzene disperse dyes and related compounds in house dust and their correlations with other organic contaminant classes.

Azobenzene disperse dyes are the fastest-growing category of commercial dyestuffs and are implicated in the literature as potentially allergenic. In the indoor environment, these dyes may be shed from various textiles, including clothing and upholstery and accumulate in dust particles potentially leading to exposure in young children who have higher exposure to chemicals associated with dust due to their crawling and mouthing behaviors. Children may be more vulnerable to dye exposure due to their developing immune systems, and therefore, it is critical to characterize azobenzene disperse dyes in children's home environments. Here, we investigate azobenzene disperse dyes and related compounds in house dust samples (n = 124) that were previously analyzed for flame retardants, phthalates, pesticides and per- and polyfluoroalkyl substances (PFAS). High-resolution mass spectrometry was used to support both targeted and suspect screening of dyes in dust. Statistical analyses were conducted to determine if dye concentrations were related to demographic information. Detection frequencies for 12 target dyes ranged from 11% to 89%; of the dyes that were detected in at least 50% of the samples, geometric mean levels ranged from 32.4 to 360 ng/g. Suspect screening analysis identified eight additional high-abundance azobenzene compounds in dust. Some dyes were correlated to numerous flame retardants and several antimicrobials, and statistically higher levels of some dyes were observed in homes of non-Hispanic Black mothers than in homes of non-Hispanic white mothers. To our knowledge, this is the most comprehensive study of azobenzene disperse dyes in house dust to date. Future studies are needed to quantify additional dyes in dust and to examine exposure pathways of dyes in indoor environments where children are concerned.

Azo dyes in the food industry: Features, classification, toxicity, alternatives, and regulation.

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.

Highly sensitive voltammetric determination of Allura Red (E129) food colourant on a planar carbon fiber sensor modified with shungite.

This article presents an original planar carbon fiber electrode (PCFE), in which shungite (SHU) is used as a modifier for the first time. Shungite is a unique natural nanostructured composite consisting of carbon in the form of aggregated graphene stacks, oxides of silicon, titanium, aluminum, iron, magnesium, potassium, etc. Macro- and micro-elements, biologically active components that are present in shungite provide it with attractive antioxidant properties, make it a biocompatible and environmentally friendly material that meets the principles of green chemistry. A unique supramolecular structure of shungite carbon presents a multilayer globular-cluster formation with mesopores in the internal volume. It determines specific physical, chemical, catalytic, and adsorption properties of shungite. Carbon fiber with an irregular 3D structure was used as an effective electrode platform for strong immobilization of shungite. The PCFE was fabricated using a simple and scalable hot lamination technology that produces very low cost flexible planar electrodes. The sensor (SHU/PCFE) was characterized by scanning electron microscopy; electrochemical impedance analysis; cyclic, differential-pulse and stripping voltammetry. The SHU/PCFE showed a 2.5-fold increase in the electroactive surface area, a 1.8-fold decrease in the electron transfer resistance compared with the bare PCFE. Under optimal experimental conditions and preconcentration at +0.2 V (vs. Ag/AgCl) 180 s, the developed sensor allowed the quantification of Allura Red in the ranges of 0.001-0.1 and 0.1-2 µmol L-1 with an extremely low detection limit of 0.36 nmol L-1. Moreover, this convenient and cost-effective sensor also has good repeatability, stability and anti-interference ability. The interfering effect of sweeteners and preservatives in the determination of Allura Red does not exceed 3.6%. The practical application of the SHU/PCFE was demonstrated using drink samples, lollipops and pharmaceuticals.

The Flexibility of ß-Content, γ-Confidence Tolerance Intervals to Qualimetry a Simultaneous 22 Aromatic Amines Derived from Azo Dyes in Fabric Using a Sensitive GC-MS Technique.

BACKGROUND: Azo dyes are among the most widely used dyes in the textile industry, releasing a series of carcinogenic aromatic amines that can be absorbed through the skin. OBJECTIVE: This work aims to show that 22 azo dye amines in a textile matrix can be quantified using a GC-MS method. METHODS: Based on the notion of total error and ß-content, γ-confidence tolerance intervals (ß,γ-CCTI), a chemometric approach known as the "uncertainty profile" has been used to completely validate a GC-MS method for the simultaneous assay of 22 azo amines in fabrics. According to International Organization for Standardization (ISO) in ISO 17025 guidelines, analytical validation and measurement uncertainty estimates have evolved to be two main principles for ensuring the accuracy of analytical results and controlling the risk associated with their use. RESULTS: The calculated tolerance intervals allowed for the determination of the uncertainty limits at each concentration level. These limits when compared to the acceptable limits show that a significant portion of the expected outcomes is in conformity. Additionally, the relative expanded uncertainty values, calculated with a proportion of 66.7% and a 10% risk, do not exceed 27.7, 12.2, and 10.9% for concentration levels 1, 15, and 30 mg/L, respectively. CONCLUSION: The capability and flexibility of the ß-content, γ-confidence intervals have been established through the use of this innovative approach to carrying out qualimetry of the GC-MS method depending on the behavior, required conformity proportion, and acceptable tolerance limits of each amine. HIGHLIGHTS: An efficient GC-MS technique for the simultaneous determination of 22 azo amines in a textile matrix has been developed. Analytical validation using a new strategy based on the uncertainty concept is reported, uncertainty associated to measurement results is estimated, and the applicability of our approach to the GC-MS method is investigated.

Environmentally-friendly supramolecular solvent microextraction method for rapid identification of Sudan I-IV from food and beverages.

A new ultrasonically assisted supramolecular solvent-based microextraction (UA-SUPRAS-ME) method has been reported. This technique is one of the green methods for rapid microextraction and determination of Sudan I, II, III and IV dyes from food and beverage samples and the study investigated the effects of various parameters such as centrifugation time, 1-octanol volume, pH, supramolecular solvent type, THF volume, ultrasonication time on the optimization of the microextraction process. Addition and recovery of the method were carried out at two different concentrations (10 and 100 ng mL-1) to food and beverage samples and the accuracy of the method was determined. Sudan I dye was detected in red pepper and hot sauce from food samples. Extraction recovery values were found between 90.6 % and 102.5 % which are promising compared to many other methods.

Broken into pieces: The challenges of determining sulfonated azo dyes in biological reactor effluents using LC-ESI-MS/MS analysis.

Most studies on the biodegradation of textile azo dyes use color as parameter for measuring the efficiency of degradation. Although widely employed, spectrophotometric methods are susceptible to the interference of metabolites or degradation products from the biological treatment. We propose a method for determination of a model sulfonated azo dye (Direct Black 22, DB22) in wastewater using solid-phase extraction (SPE) and liquid chromatography - electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS). MS analysis in negative electrospray ionization mode showed DB22 as the most abundant precursor ion, corresponding to [M-3Na + H]2-, which yields two radical anions of m/z 370.1 and m/z 645 after MS/MS fragmentation by collision-induced dissociation (CID). Calibration curve presented adequate linearity and precision in the range of 120-1500 ng mL-1, and recovery and detection limit were appropriate to the typically employed working concentrations. Nevertheless, we observed that standard heating of DB22 under alkaline conditions to simulate the production of wastewater during dye-baths resulted in loss of MS/MS signal, without affecting color. Further analysis showed that DB22 undergoes hydrolysis and does not remain unaltered in solution. Alternative methods of hydrolysis evaluated resulted in no MS/MS signal as well. SPE-LC-ESI-MS/MS analysis evidenced the structural change of DB22 in aqueous solution while the dyeing-capacity was preserved. This technique has also the potential of being tailored to consider the detection of the hydrolyzed fragments of azo dyes in wastewater for appropriate quantification, but it was not the scope of the current step of this research. Color remains as a more reliable parameter for monitoring azo compounds which are unstable in aqueous solution, while a more robust and holistic method needs to be developed for the speciation of the DB22 products of thermal hydrolysis.

Sub-micro electrochemical recognition of carmoisine, sunset yellow, and tartrazine in fruit juices using P(ß-CD/Arg)/CysA-AuNPs/AuE.

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.

Banned Sudan dyes in spices available at markets in Karachi, Pakistan.

Sudan dyes were investigated in branded and non-branded spices, commonly available in the markets of Karachi, Pakistan. High performance liquid chromatography (HPLC) with a variable wavelength detector (VWD) was applied to determine Sudan dyes I-IV. The non-branded samples had higher concentrations of Sudan dyes than the maximum limits of 0.1 mg/kg. The highest concentration of Sudan dye (I) was found in turmeric powder (8460 mg/kg) and the lowest concentration (1.50 mg/kg) of Sudan (IV) in Chaat Masala. This indicates that the use of non-branded spices is not safe, whereas no Sudan dye was found in the branded spice samples. Further studies regarding the higher carcinogenic risk posed by Sudan dye adulterated spices in Pakistan is strongly advised.

Enhanced artificial intelligence for electrochemical sensors in monitoring and removing of azo dyes and food colorant substances.

It is necessary to determine whether synthetic dyes are present in food since their excessive use has detrimental effects on human health. For the simultaneous assessment of tartrazine and Patent Blue V, a novel electrochemical sensing platform was developed. As a result, two artificial azo colorants (Tartrazine and Patent Blue V) with toxic azo groups (-NN-) and other carcinogenic aromatic ring structures were examined. With a low limit of detection of 0.06 µM, a broad linear concentration range 0.09µM to 950µM, and a respectable recovery, scanning electron microscopy (SEM) was able to reveal the excellent sensing performance of the suggested electrode for patent blue V. The electrochemical performance of an electrode can be characterized using cyclic and differential pulse voltammetry, and electrochemical impedance spectroscopy. Moreover, the classification model was created by applying binary classification assessment using enhanced artificial intelligence comprises of support vector machine (SVM) and Genetic Algorithm (GA), respectively, a support vector machine and a genetic algorithm, which was then validated using the 50 dyes test set. The best binary logistic regression model has an accuracy of 83.2% and 81.1%, respectively, while the best SVM model has an accuracy of 90.3% for the training group of samples and 81.1% for the test group (RMSE = 0.644, R2 = 0.873, C = 205.41, and = 5.992). According to the findings, Cu-BTC MOF (copper (II)-benzene-1,3,5-tricarboxylate) has a crystal structure and is tightly packed with hierarchically porous nanomaterials, with each particle's edge measuring between 20 and 37 nm. The suggested electrochemical sensor's analytical performance is suitable for foods like jellies, condiments, soft drinks and candies.

Carbon-paste electrode modified by ß-cyclodextrin as sensor for voltammetric determination of Tartrazine and Carmoisine from one drop.

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 ß-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.

Ultrasensitive detection of food colorant sunset yellow using nickel nanoparticles promoted lettuce-like spinel Co3O4 anchored GO nanosheets.

Synthetic food colorants are extensively used across the globe regardless of the fact that they induce deleterious side effects when used in higher amounts. In this work, a novel electrochemical sensor based on nickel nanoparticles doped lettuce-like Co3O4 anchored graphene oxide (GO) nanosheets was developed for effective detection of sulfonated azo dye sunset yellow widely used as a food colorant. Hydrothermal synthesis was adopted for the preparation of lettuce-like spinel Co3O4 nanoparticles and Ni-Co3O4 NPs/GO nanocomposite was prepared using ecofriendly and economical sonochemical method. The prepared ternary nanocomposite meticulously fabricated on a screen-printed carbon electrode exhibited remarkable electrocatalytic activity towards sunset yellow determination. This is apparent from the resultant well-defined and intense redox peak currents of Ni-Co3O4 NPs/GO nanocomposite modified electrode at very low potentials. The developed sunset yellow sensor exhibited a high sensitivity of 4.16 µA µM-1 cm-2 and a nanomolar detection limit of 0.9 nM in the linear range 0.125-108.5 µM. Furthermore, experiments were conducted to affirm excellent stability, reproducibility, repeatability, and selectivity of proposed sensor. The practicality of sunset yellow determination using the developed sensor was analyzed in different varieties of food samples including jelly, soft drink, ice cream, and candy resulting in recovery in the range of 96.16%-102.56%.

QuEChERS sample preparation integrated to dispersive liquid-liquid microextraction based on solidified floating organic droplet for spectrometric determination of sudan dyes: A synergistic approach.

In this project, a synergistic approach has been proposed where a quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation technique was developed for the extraction of sudan III and sudan IV dyes in different spices prior to its dispersive liquid-liquid microextraction based on solidified floating organic droplet (DLLME-SFO). Initially, the sample was extracted by QuEChERS method and then preconcentrated through DLLME-SFO followed by spectrophotometric detection. All the experimental parameters i.e., volume of extraction solvent, pH, acetonitrile to water ratio, temperature, centrifugation rate and time, and sample volume were optimized. Limit of detection (LOD) calculated for sudan III and sudan IV were 0.42 and 0.35 mg/L, respectively. Excellent recoveries were obtained in the range of 98.29-99.88%. After validation through standard addition methodology, the developed QuEChERS@DLLME-SFO method was successfully applied to determine sudan (III-IV) dyes in real spices samples. Integration of QuEChERS and DLLME-SFO was found to be a suitable substitute to eliminate the usage of costly primary secondary amines and other sorbents. The synergistic approach of QuEChERS and DLLME-SFO with the aid of UV/visible spectrophotometry makes it prompt, cost effective technique with excellent analytical figures of merit.

Determination of Illegally Used Chemical Dyes in the Chinese Herbal Medicine "Red Flower Oil".

BACKGROUND: Red flower oil is a group of herbal medicinal liniments widely used in China and Southeast Asia. The color of red flower oil is adjusted to red or brownish-red by adding natural dyes. OBJECTIVE: The objective of this study is to identify and quantify the synthetic dyes illegally used in red flower oil. METHODS: Thirty-two batches of red flower oil (from nine manufacturers) were collected from different cities in China. High-performance liquid chromatography-diode array detection-mass spectrometry (HPLC-DAD-MS) analysis was performed to identify the chemical dyes in the samples, and high-performance liquid chromatography-diode array detection (HPLC-DAD) was used to quantify the chemical dyes. RESULTS: Sudan I, Sudan IV, and Solvent Red 207 were detected in nine batches of preparations (from three manufacturers) with concentration ranges of 101.7-214.9 µg/mL for Sudan I, 24.0-41.0 µg/mL for Sudan IV, and 147.5-221.7 µg/mL for Solvent Red 207. CONCLUSION: In present study, sudan I, sudan IV, and solvent red 207 were detected in red flower oil. The control of chemical dyes in food and drug should be further studied and not limited to sudan dyes. HIGHLIGHTS: It is the first report about the detection of solvent red 207 in food and drug. The illegal use of those chemical dyes should be regarded as serious violation of good manufacturing practice (GMP) and might be dangerous for the patients.

Electromagnetic dispersive solid-phase extraction based on polyaniline-coated magnetite/silica materials for the determination of Sudan red I in drinks.

By replacing the permanent magnet with an electromagnet, traditional magnetic solid-phase extraction was developed into electromagnetic dispersive solid-phase extraction. A simple operation of power on and off can realize the separation of adsorbents from solutions easily. The improvement makes it possible for the automation of the determination of Sudan Red I by high-performance liquid chromatography. After series of optimization, a trace amount of Sudan red I was well-determined, and excellent linearity was achieved in the range of 0.005 to 1 mg/L with the correlation coefficient (R2 ) = 0.997. The limit of detection with a signal-to-noise ratio of 3 was found to be 0.001 mg/L. The spiked recoveries of Sudan red I for the samples ranged from 93.6 to 104.9%. Moreover, the adsorbent could be recycled at least ten times. The results show that the electromagnetic dispersive solid-phase extraction combined with high-performance liquid chromatography is a rapid, eco-friendly, effective, and sensitive determination method with fascinating automation potential and high practical applicability.