Determination of Sudan dyes in chili products by micellar electrokinetic chromatography-MS/MS using a volatile surfactant

Advanced detection tools in food fraud: A systematic review for holistic and rational detection method based on research and patents

Modern food chain supply management necessitates the dire need for mitigating food fraud and adulterations. This holistic review addresses different advanced detection technologies coupled with chemometrics to identify various types of adulterated foods. The data on research, patent and systematic review analyses (2018-2023) revealed both destructive and non-destructive methods to demarcate a rational approach for food fraud detection in various countries. These intricate hygiene standards and AI-based technology are also summarized for further prospective research. Chemometrics or AI-based techniques for extensive food fraud detection are demanded. A systematic assessment reveals that various methods to detect food fraud involving multiple substances need to be simple, expeditious, precise, cost-effective, eco-friendly and non-intrusive. The scrutiny resulted in 39 relevant experimental data sets answering key questions. However, additional research is necessitated for an affirmative conclusion in food fraud detection system with modern AI and machine learning approaches.

Aptamer-modified paper-based analytical devices for the detection of food hazards: Emerging applications and future perspective

Food analysis plays a critical role in assessing human health risks and monitoring food quality and safety. Currently, there is a pressing need for a reliable, portable, and quick recognition element for point-of-care testing (POCT) to better serve the demands of on-site food analysis. Aptamer-modified paper-based analytical devices (Apt-PADs) have excellent characteristics of high portability, high sensitivity, high specificity, and on-site detection, which have been widely used and concerned in the field of food safety. The article reviews the basic components and working principles of Apt-PADs, and introduces their representative applications detecting food hazards. Finally, the advantages, challenges, and future directions of Apt-PADs-based sensing performance are discussed, to provide new directions and insights for researchers to select appropriate Apt-PADs according to specific applications.

A sharp and selective fluorescence paper-based sensor based on inner filter effect for ratiometric detection of four Sudan dyes in food matrix

The addition of Sudan dyes with carcinogenic effects to food threatens human health. Herein, a ratiometric fluorescence strip consisting of core-shell upconversion particles (NaYF4:Yb,Tm@NaYF4:Yb,Er), metal-organic frameworks and dual-template molecularly imprinted polymers was developed to selectively and sensitively detect four Sudan dyes based on inner filter effect (detection time only takes 8 min). The high adsorption capacity of metal-organic frameworks and the greater overlap between the emission of NaYF4:Yb,Tm@NaYF4:Yb,Er and the absorbance of four Sudan dyes enable the signal responses to be more sensitive. The limits of detection in chilli powder samples are as low as 29.87 ng/g, 37.55 ng/g, 47.89 ng/g and 51.02 ng/g, with satisfactory recovery (93.32-103.4%) and minor relative standard deviations (≤4.3%). This method broadens the idea for low-cost and portable detection of multiple illegal additives in complex substrates with high selectivity and sensitivity based on one kind of fluorescent strip.

Dispersive liquid-liquid microextraction followed by sweeping micellar electrokinetic chromatography-tandem mass spectrometry for determination of six breast cancer drugs in human plasma

Herein, we have developed a novel method of aqueous-sample dispersive liquid-liquid microextraction (AqS-DLLME) followed by sweeping micellar electrokinetic chromatography-tandem mass spectrometry (MEKC-MS/MS) for simultaneous determination of breast cancer drugs letrozole, anastrozole, palbociclib, ribociclib, abemaciclib, and fulvestrant in human plasma. Coupling of MEKC to MS was possible due to the use of ammonium perfluorooctanoate (APFO) as a volatile surfactant. The MEKC and MS conditions were optimized to achieve a fast, sensitive, selective, and green analysis enabling full separation of the analytes within 16 min. Electrophoretic buffer was 125 mM APFO at apparent pH 10.5 in 32 % MeOH, while sheath liquid was 70 % MeOH with 0.2 % formic acid, delivered at 10 µL/min. Excellent extraction recoveries from plasma ranging from 89.4 to 104.9 % were obtained with a combination of protein precipitation and DLLME. The developed method was validated according to the ICH guidelines. Remarkable selectivity, accuracy (bias < 6.7 %), precision (RSD < 15.8 %), and stability (bias < 10.4 %) with insignificant matrix effect (RSD < 14.0 %) and no carry-over were obtained over a wide range of concentrations. Linearity with inter-day slope RSD lower than 8.7 % was demonstrated. With this method, very low concentrations could be detected after the injection of only 68.7 nL of the sample. The method was applied to plasma samples from six women currently receiving breast cancer treatment. Determined concentrations of the drugs of interest agreed with concentrations found in clinical studies, thus proving the suitability of the developed method for therapeutic drug monitoring as a superior alternative to published LC-MS methods.

Rapid determination of 61 acid dyes in chili paste, hotpot seasoning, and bearnaise using double liquid-liquid extraction and UHPLC-Q-Orbitrap-MS

The aims of this study were to establish a novel method for simultaneously determining 61 acid dyes in chili, hotpot seasoning, and bearnaise sauce using double liquid-liquid extraction (d-LLE) technology. A mixture of water, methanol, and dichloromethane (1:3:1, v/v/v) was used as the extraction solution, which was actively separated into aqueous and organic phases at a fixed ratio. The clean-up step was initially completed by discarding the organic phase layer, which contained abundant lipophilic compounds. Subsequently, the aqueous phase was further separated by salting out, which effectively removed interference from the highly hydrophilic compounds. As a result of these two purification steps, the matrix suppression effect was significantly reduced by a minimum of 16.9%. Finally, the extract was analyzed using an ultrahigh-performance liquid chromatography-quadrupole Orbitrap mass spectrometer (UHPLC-Q-Orbitrap-MS), and the characteristic ion fragments (SO3 - , m/z 79.9557) of the acid dyes were utilized for the preliminary qualitative analysis. The results showed that the 61 acid dyes showed a good linear relationship in the range of 0.01-0.2 µg/mL, and the limit of quantification (LOQ) was 0.01 mg/kg. The average recoveries were 74.3%-99.7%, with relative standard deviations (RSD) ≤10%. The proposed method can rapidly identify and quantify acid dyes in complex foods at a low cost, with high sensitivity and reliability.

Strategies for capillary electrophoresis: Method development and validation for pharmaceutical and biological applications-Updated and completely revised edition

This review is in support of the development of selective, precise, fast, and validated capillary electrophoresis (CE) methods. It follows up a similar article from 1998, Wätzig H, Degenhardt M, Kunkel A. "Strategies for capillary electrophoresis: method development and validation for pharmaceutical and biological applications," pointing out which fundamentals are still valid and at the same time showing the enormous achievements in the last 25 years. The structures of both reviews are widely similar, in order to facilitate their simultaneous use. Focusing on pharmaceutical and biological applications, the successful use of CE is now demonstrated by more than 600 carefully selected references. Many of those are recent reviews; therefore, a significant overview about the field is provided. There are extra sections about sample pretreatment related to CE and microchip CE, and a completely revised section about method development for protein analytes and biomolecules in general. The general strategies for method development are summed up with regard to selectivity, efficiency, precision, analysis time, limit of detection, sample pretreatment requirements, and validation.

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.

Rapid determination of 93 banned industrial dyes in beverage, fish, cookie using solid-supported liquid-liquid extraction and ultrahigh-performance liquid chromatography quadrupole orbitrap high-resolution mass spectrometry

Banned industrial dyes are composed of a large number of chemicals with diverse physical and chemical properties, making their simultaneous determination a challenging task. A one-step extraction and purification of 93 banned industrial dyes from beverage, fish and cookie sample methods was proposed by using solid supported liquid-liquid extraction (SLE). The extract was analyzed by ultrahigh-performance liquid chromatography quadrupole orbitrap high-resolution mass spectrometry (UPLC-Q-Orbitrap-HRMS). The quantitative and qualitative mode adopts Q-Orbitrap-HRMS full scan MS (full scan MS¹) and data-dependent MS/MS (dd-MS²) acquisition mode. The mass resolution was screened under 70,000 FWHM for full-scan MS¹ and 35,000 FWHM for dd-MS². Linearity was observed in the range of 0.01 ∼ 0.5 μg/mL and the limits of quantification were 0.04 ∼ 0.2 mg/kg for 93 dyes. The average recoveries were 70.5-105.8%, with RSD ≤ 10%. The proposed method has the ability to simultaneously screen many banned dyes in foods with high throughput, sensitivity and reliability.

A surfactant-mediated microextraction of synthetic dyes from solid-phase food samples into the primary amine-based supramolecular solvent

An effective and simple surfactant-mediated microextraction of synthetic dyes from solid-phase food samples into the primary amine-based supramolecular solvents is presented for the first time. The developed procedure involved two stages: (i) an isolation of dyes from a solid-phase food sample into a micellar solution of the primary amine; (ii) a preconcentration of the extracted dyes into the supramolecular solvent phase generated from the obtained micellar solution under a coacervation process. The microextraction procedure was applied for the determination of synthetic dyes in confectionery, dried fruits, and spices samples. The supramolecular solvent formed from aqueous micelle aggregates of 1-octylamine due to coacervation induced by thymol provided maximum extraction recovery values for synthetic dyes. In the proposed two-stage extraction procedure the micellar solution of primary amine was a media for analytes isolation from solid-phase and their followed preconcentration.

Amplified electrochemical sensor employing Ag NPs functionalized graphene paper electrode for high sensitive analysis of Sudan I

In this study, a high-performance flexible reduced graphene oxide (rGO) paper electrode composed of silver nanoparticles (Ag NPs) for the detection of Sudan I was fabricated. Ag NPs were doped with rGO nanoheets by self-assemble and assembled into a paper electrode with layer-by-layer structure via vacuum filtration. Thanks to the highly efficient electrocatalysis of Ag NPs towards reduction of azo bond, the as-prepared hybrid paper can be used alone as a flexible sensor for the detection of Sudan I in chili powder, with the high sensitivity (22.93 μA μmol/L) and the low detection limit (41.3 nmol/L). The sensor also expressed good selectivity, repeatability, reproducibility, stability and recovery between 96.1% and 101.8% (RSD < 6%). With the advantages of low-cost and scalable production capacity, such Ag NPs/rGO functional papers can be used as flexible disposable sensors for electrochemical detection of Sudan I.

Capillary electromigration methods for food analysis and Foodomics: Advances and applications in the period February 2019-February 2021

This work presents a revision of the main applications of capillary electromigration methods in food analysis and Foodomics. Articles that were published during the period February 2019-February 2021 are included. The work shows the multiple CE methods that have been developed and applied to analyze different types of molecules in foods. Namely, CE methods have been applied to analyze amino acids, biogenic amines, carbohydrates, chiral compounds, contaminants, DNAs, food additives, heterocyclic amines, lipids, secondary metabolites, peptides, pesticides, phenols, pigments, polyphenols, proteins, residues, toxins, vitamins, small organic and inorganic compounds, as well as other minor compounds. The last results on the use of CE for monitoring food interactions and food processing, including recent microchips developments and new applications of CE in Foodomics, are discussed too. The new procedures of CE to investigate food quality and safety, nutritional value, storage and bioactivity are also included in the present review work.

Highly Selective and Sensitive Benzimidazole Based Bifunctional Sensor for Targeting Inedible Azo Dyes in Red Chilli, Red Food Color, Turmeric Powder, and Cu(Ii) in Coconut Water

In this study, a simple Benzimidazole based bifunctional chemosensor 4-(2-(3,4-dimethoxyphenyl)-1H-benzo[d]imidazol-6-yl) benzene-1,2-diamine, L was synthesized and characterized. The sensor proved to be selective and sensitive towards detecting banned azo dyes Sudan Dye I, II, and Metanil Yellow via fluorescence turn-off response. The proposed mechanism of fluorescence quenching was the inner filter effect. LODs for Sudan I, II, and Metanil Yellow were found to be 0.009 µM, 0.012 µM, and 0.0073 µM, respectively. The developed chemosensor also showed a colorimetric response towards Cu (II) ions via an apparent color change from yellow to pink. LOD for Cu (II) ions was found to be 1.2 µM. The synthesized benzimidazole based bifunctional chemosensor was adequately tested to determine Sudan I in Red chili powder and red Food color samples, Metanil yellow in turmeric powder, and Cu(II) packaged coconut water.

Magnetic and thermal dual-sensitive core-shell nanoparticles for highly preconcentration and measurement of Sudan red pollutants

Recently, thermal-sensitive polymers absorbed much more concerns, and the goal of present work was to modify magnetic nanoparticles with N-isopropylacrylamide (NIPAM) and methyl 3,3-dimethylacrylate (DMMA) for obtaining thermal and magnetic dual-sensitive nanoparticles based on silica coated nanoscale zero valent iron and thermal-sensitive polymers (Fe@p(NIPAM-co-DMMA)). Fe@p(NIPAM-co-DMMA) nanoparticles were fabricated and possessed excellent adsorption ability for Sudan pollutants in aqueous samples. A rapid extraction and separation approach utilizing synthesized dual-sensitive nanomaterials was designed and developed before analysis by liquid chromatography (HPLC). Upon the enrichment factors as their optimal values, the established method gained wonderful linearity over the range of 0.05-500 μg L^-1. The precisions of proposed method were all lower than 3.87%. The validating experiments ensured that this developed method provided with satisfied recoveries in the range of 97.4-102.6% from spiked real water samples, which affirmed that this method was a reliable monitoring tool for Sudan pollutants in water and food samples, etc.

Preparation of Polyamidoamine Dendrimer Modified Magnetic Nanoparticles and Its Application for Reliable Measurement of Sudan Red Contaminants in Natural Waters at Parts-Per-Billion Levels

The health threat from Sudan red dyes has been the subject of much attention in recent years and is crucial to design and establish reliable measurement technologies. In the present study, a new magnetic nanomaterial, polyamidoamine dendrimer-modified magnetic nanoparticles (Gn-MNPs), was synthesized and characterized. The nanomaterials had good adsorption capacity for Sudan dyes from natural waters. G1.5-MNPs possessed excellent adsorption capacity and a linear adsorption relationship over the range from 0.02 to 300 μg L⁻¹ of Sudan dyes with relative coefficients all larger than 0.996. The sensitivity of the proposed method was excellent with detection limits over the range from 1.8 to 5.5 ng L⁻¹ and the precision was less than 3.0%. G1.5-MNPs showed a remarkable application potential for the enrichment of trace environment pollutants in aqueous samples and the developed method based on this nanomaterial could be a robust and reliable alternative tool for routine monitoring of such pollutants.

Benzo[a]pyrene-Induced Genotoxicity in Rats Is Affected by Co-Exposure to Sudan I by Altering the Expression of Biotransformation Enzymes

The environmental pollutant benzo[a]pyrene (BaP) is a human carcinogen that reacts with DNA after metabolic activation catalysed by cytochromes P450 (CYP) 1A1 and 1B1 together with microsomal epoxide hydrolase. The azo dye Sudan I is a potent inducer of CYP1A1/2. Here, Wistar rats were either treated with single doses of BaP (150 mg/kg bw) or Sudan I (50 mg/kg bw) alone or with both compounds in combination to explore BaP-derived DNA adduct formation in vivo. Using ³²P-postlabelling, DNA adducts generated by BaP-7,8-dihydrodiol-9,10-epoxide were found in livers of rats treated with BaP alone or co-exposed to Sudan I. During co-exposure to Sudan I prior to BaP treatment, BaP-DNA adduct levels increased 2.1-fold in comparison to BaP treatment alone. Similarly, hepatic microsomes isolated from rats exposed to Sudan I prior to BaP treatment were also the most effective in generating DNA adducts in vitro with the activated metabolites BaP-7,8-dihydrodiol or BaP-9-ol as intermediates. DNA adduct formation correlated with changes in the expression and/or enzyme activities of CYP1A1, 1A2 and 1B1 in hepatic microsomes. Thus, BaP genotoxicity in rats in vivo appears to be related to the enhanced expression and/or activity of hepatic CYP1A1/2 and 1B1 caused by exposure of rats to the studied compounds. Our results indicate that the industrially employed azo dye Sudan I potentiates the genotoxicity of the human carcinogen BaP, and exposure to both substances at the same time seems to be hazardous to humans.

Single-emission dual-enzyme magnetosensor for multiplex immunofluorometric assay of adulterated colorants in chili seasoning

In this work, a single-emission, dual-enzyme immunofluorometric magnetosensor was fabricated to simultaneously detect three illegal colorants in chili seasoning. Specifically, two enzymatic reactions catalyzed by horse radish peroxidase-labeled Rhodamine (RhB) antibody and glucose oxidase-labeled Sudan dyes (SuDs) antibody were performed within a functional microfluidic chip, leading to production of strongly fluorescent Resorufin. In addition, a compact analyzer assisted by a smartphone was developed to quantify signals. Compared with the available multiplex optical biosensors, this work demonstrated four superiorities: 1) Simple optical structure. Only single wavelength excitation/emission module was needed; 2) High multiplexing capacity through spatial resolution and signal resolution; 3) Precise determination by discriminant analysis; 4) Easy-operated and high-throughput parallel detection on 16-channel chips. Ultralow detection limits for RhB (0.0072 ng/mL), Sudan I (0.0040 ng/mL) and Sudan II (0.0260 ng/mL) were obtained by this magnetosensor, which opens a new approach in field detection of multiplex illegal dyes in food system.

[Annual review of capillary electrophoresis technology in 2020]

该文为2020年毛细管电泳(capillary electrophoresis, CE)技术年度回顾。归纳总结了以“capillary electrophoresis-mass spectrometry”或“capillary isoelectric focusing”或“micellar electrokinetic chromatography”或“capillary electrophoresis”为关键词在ISI Web of Science数据库中进行主题检索得到的2020年CE技术相关研究论文222篇,以及中文期刊《分析化学》和《色谱》中CE技术相关的研究论文37篇。对2020年影响因子(IF)≥5.0的Analytical Chemistry, Food Chemistry, Analytica Chimica Acta和Talanta等13本期刊的38篇文章报道的科研工作作了逐一介绍;对IF<5.0的期刊中CE技术报道较为集中的Journal of Chromatography A和Electrophoresis两本分析化学类期刊发表40篇文章中的代表性内容作了综合介绍;对重要的中文期刊《分析化学》出版的“核酸适配体专刊”和《色谱》出版的2期CE技术专刊所收录的37篇文章中的工作作了总体介绍。总体来说,2020年CE技术发展趋势仍以毛细管电泳-质谱(CE-MS)的新方法和新应用最为突出,主要集中在CE-MS与电化学检测、固相萃取以及多种毛细管电泳模式的联用方面,CE-MS接口相关的报道较前几年有所减少;常规CE技术则以胶束电动毛细管色谱(MEKC)在复杂样本分析、浓缩富集应用为主,尤其在食品和药品等复杂基质样本分析方面的报道较为集中;此外,我国CE相关领域专家学者的科研成果涵盖了CE在生命科学、临床医学、医药研发、环境科学、天然产物、食品分析等领域的应用,代表了国内CE科研应用水平和现状。

Analysis of fluorinated compounds by micellar electrokinetic chromatography - mass spectrometry

Micellar electrokinetic chromatography (MEKC) is a good separation technique with high efficiency, high selectivity and simple preparation process. Hyphenation of MEKC with mass spectrometry (MS) could extend its application in complex sample analysis. However, direct coupling MEKC using commonly used surfactants like sodium dodecyl sulfate (SDS) with ESI-MS will lead to strong signal suppression. In this work, a MEKC-MS method using volatile ammonium perfluorooctanoate as surfactant was developed. The MS compatibility of ammonium perfluorooctanoate was investigated. The result revealed that there is no signal suppression even the concentration of ammonium perfluorooctanoate was up to 300 mM. Meanwhile, we found that ammonium perfluorooctanoate used as surfactant in MEKC provided powerful F-F interaction and hydrophobic interaction, which was beneficial for separation of fluorinated compounds. Using the ammonium perfluorooctanoate based MEKC method, several groups of fluorinated compounds, which cannot be separated using non-fluorinated surfactants like lauric acid and SDS based MEKC method, were baseline separated. Finally, the MEKC-ESI-MS method was successfully applied for analysis of two herbicides including fluometuron and fenuron in lake water samples with high separation efficiency, high sensitivity, good linearity and reproducibility.

Ultrasound-assisted hydrophobic deep eutectic solvent based solid-liquid microextraction of Sudan dyes in spice samples

An environmentally friendly, simple method was carried out with the help of an ultrasonic assisted solid-liquid microextraction technique using a new deep eutectic solvent (DES) for the extraction and determination of Sudan dyes (I-IV) in spice samples. In this method, parameters affecting the optimization were researched and optimized such as DES composition, DES volume, ultrasonic time, temperature and, centrifuge time. The analytical performance of the developed method was quite satisfactory, the R² values were higher than 0.9989, and the limits of quantification were <1.17 μg g^-1. Two different concentrations (10-50 μg g^-1) were spiked to Chili peppers, paprika, cumin and sumac spices for the applicability and accuracy of the developed microextraction method. Some of these spices were found to contain Sudan I and IV dyes. The recovery values for spiked samples were found to be between 85.55% and 99.29% and relative standard deviations were found to be <3.17% when using a 10 μg g^-1 Sudan dyes concentration. The results showed that the developed method can be successfully applied for extraction and determination of Sudan dyes in spice samples.