Rapid micropreparation procedure for the gas chromatographic–mass spectrometric determination of BHT, BHA and TBHQ in edible oils

Ratio-fluorescence detection of tert-butylhydroquinone based on non-conjugated polymer dots and gold nanoclusters

A novel ratiometric fluorescent probe based on non-conjugated polymer dots (NCPDs) and gold nanocluster (AuNCs) was constructed to determine tert-butylhydroquinone (TBHQ). The probe exhibited dual emission peaks at 480 nm and 630 nm under 370 nm excitation. The fluorescence of AuNCs was quenched by TBHQ due to strong electrostatic interactions, whereas the emission of NCPDs increased. The ratio of fluorescence intensity at 480 nm to 630 nm (F480 / F630) was monitored as analytical signal response. The probe have been utilized for the detection of TBHQ with good linear relationship in the range of 0.2 to 60 μg/mL. The limit of detection (LOD) and the limit of quantitation (LOQ) were 0.048 μg/mL and 0.159 μg/L, respectively. Three levels of spiked-in TBHQ concentrations were obtained with recovery rates from 80 % to 102 %. The present study provided an effective ratiometric fluorescence method for selective screening of TBHQ in food samples.

Highly Sensitive Electrochemical Determination of Butylated Hydroxyanisole in Food Samples Using Electrochemical-Pretreated Three-Dimensional Graphene Electrode Modified with Silica Nanochannel Film

The sensitive detection of antioxidants in food is essential for the rational control of their usage and reducing potential health risks. A simple three-dimensional (3D) electrode integrated with an anti-fouling/anti-interference layer possesses great potential for the direct and sensitive electrochemical detection of antioxidants in food samples. In this work, a 3D electrochemical sensor was developed by integrating a 3D graphene electrode (3DG) with vertically ordered mesoporous silica film (VMSF), enabling highly sensitive detection of the common antioxidant, butylated hydroxyanisole (BHA), in food samples. A simple electrochemical polarization was employed to pre-activate the 3DG electrode (p3DG), enhancing its hydrophilicity. Using the p3DG as the supporting electrode, stable modification of VMSF was achieved using the electrochemical assisted self-assembly (EASA) method, without the need for any adhesive agents (VMSF/p3DG). Taking BHA in food as a model analyte, the VMSF/p3DG sensor demonstrated high sensitivity, due to the enrichment by nanochannels, towards BHA. Electrochemical detection of BHA was achieved with a linear range of 0.1 μM to 5 μM and from 5 μM to 150 μM with a low limit of detection (12 nM). Owing to the fouling resistance and anti-interference capabilities of VMSF, the constructed 3D electrochemical sensor can be directly applied for the electrochemical detection of BHA in complex food samples.

A ratiometric electrochemical sensing strategy based on the self-assembly of Co NC/CNT and methylene blue for effective detection of the food additive tert-butylhydroquinone

It is crucial to achieve accurate and rapid detection of tert-butylhydroquinone (TBHQ) in the field of food safety, for the excessive addition of TBHQ in food is harmful to human health and evil to the environment and aquatic life. Therefore, researchers have done a lot of work on signal amplification through nanomaterials to achieve TBHQ detection, but the conventional single-signal detection strategy results in limited accuracy. In this work, an innovative and facile ratiometric electrochemical sensor for TBHQ detection was built based on advanced nanomaterial complexes carbon nanotube-encapsulated Co/nitrogen-doped carbon (Co NC/CNT) and selected internal reference signal methylene blue (MB) enhancing the accuracy by offering effective self-calibration. A linear relationship between the net peak current ratio between TBHQ and MB (ΔI (TBHQ)/ΔI (MB)) and the TBHQ concentration was obtained under the optimal experimental conditions, with two linear ranges of 0.1-20 μM and 20-100 μM and a limit of detection (LOD) of 0.054 μM (S/N = 3). Benefiting from the synergistic effects between Co NC and CNT and the ratiometric sensing strategy, the as-designed sensor for TBHQ detection showcased excellent selectivity, repeatability, reproducibility, stability, and satisfactory applicability in real edible oil samples.

A novel molecularly imprinted electrochemical sensor for the ultrasensitive detection of tert-butylhydroquinone in edible oils

Tert-butylhydroquinone (TBHQ) is widely used to increase the stability of food products; however, it is considered to be a highly unsafe preservative ingredient that has caused serious damage to human health. Thus, in this paper, a novel molecularly imprinted electrochemical sensor was designed for ultrasensitive, and selective detection of TBHQ in edible oils. The sensor was based on the molecularly imprinted polymer (MIP) synthesized with multiwalled carbon nanotube (MWCNT), and gold nanoparticle (GNP), as the coating materials, o-phenylenediamine (o-PDA) as the functional monomer, and TBHQ as the template molecule. The electrochemical behavior of MIP/GNP/MWCNT/GCE was studied using several electrochemical methods, which showed a low detection limit of 5 nM. Furthermore the sensor demostrated excellent stability, selectivity, repeatability, and reproducibility. It was successfully used to detect TBHQ in edible oils, with recoveries ranging from 98.44% to 102.09% and relative standard deviations (RSDs) of less than 2.16%, indicating that TBHQ detection in actual samples is both possible and accurate.

Fe-MOF-based fluorescent sensor with on/off capabilities for the highly sensitive detection of tert-butylhydroquinone in edible oils

In this work, a "turn off-on" fluorescent sensor was developed for highly sensitive determination of tert-butylhydroquinone (TBHQ) based on an Fe(III)-based metal-organic framework (Fe-MOF). An Fe-MOF with an octahedral structure was synthesized via a simple hydrothermal method using ferric chloride hexahydrate and 2-aminoterephthalic acid (NH2-BDC) as raw materials. The fluorescence of Fe-MOF is extremely weak owing to ligand-to-metal charge transfer (LMCT) and internal filtration effect (IFE). When the system contained TBHQ, the binding of TBHQ to Fe(III) inhibited the LMCT of the fluorescent ligand NH2-BDC to Fe(III), releasing the fluorescence of NH2-BDC and thus restoring the fluorescence. With this as the basis, a rapid, sensitive, and selective fluorescence sensor is developed for the detection of TBHQ. Under the optimal conditions, TBHQ showed good linearity with fluorescence intensity in the range of 0-1.5 × 102 μmol L-1 and a detection limit of 0.0030 μmol L-1 (S/N = 3). The selectivity, reproducibility, and stability of the developed Fe-MOF-based sensors are comprehensively studied. Finally, the practicality of the method is verified by examining the detection of TBHQ in soybean oil; the results are consistent with those obtained using conventional high-performance liquid chromatography.

NiGA MOF-based dispersive micro solid phase extraction coupled to temperature-assisted evaporation using low boiling point solvents for the extraction and preconcentration of butylated hydroxytoluene and some phthalate and adipate esters

The first-ever attempt to apply nickel gallic acid metal-organic framework (NiGA MOF) in analytical method development was done in this research by the extraction of some plasticizers from aqueous media. The greenness of the method is owing to the use of gallic acid and nickel as safe reagents and water as the safest solvent. Low boiling point solvents were applied as desorption solvents that underwent temperature-assisted evaporation in the preconcentration step. Performing the evaporation using a low-temperature water bath for a short period of time streamlines the preconcentration section. Into the solution of interest enriched with sodium sulfate, a mg amount of NiGA MOF was added alongside vortexing to extract the analytes. Following centrifugation and discarding the supernatant, a μL level of diethyl ether was added onto the analyte-loaded NiGA MOF particles and vortexed. The analyte-enriched diethyl ether phase was transferred into a conical bottom glass test tube and located in a water bath set at the temperature of 35 °C under a laboratory hood. After the evaporation, a μL level of 1,2-dibromoethane was added to the test tube and vortexed to dissolve the analytes from the inner perimeter of the tube. One microliter of the organic phase was injected into a gas chromatograph equipped with flame ionization detection. Appreciable extraction recoveries (61-98%), high enrichment factors (305-490), low limits of detection (0.80-1.74 μg L-1) and quantification (2.64-5.74 μg L-1), and wide linear ranges (5.74-1000 μg L-1) were obtained at the optimum conditions.

A fully green sample preparation method for synthetic antioxidants determination in edible oils based on natural feather fiber-supported liquid extraction

The current study proposed a novel feather fiber-supported liquid extraction (FF-SLE) method for extracting analytes from oil samples. The natural feather fibers were used as the oil support material and directly loaded in the plastic tube of a disposable syringe to construct the low-cost extraction device (∼0.5 CNY). The edible oil without any pretreatment including dilution was added directly to the extraction device, followed by the addition of the green extraction solvent of ethanol. As an example, the proposed method was applied to extract nine synthetic antioxidants from edible oils. The optimized extraction conditions for processing 0.5 g of oil were obtained when the syringe dimension was 5 mL, the extraction solvent was 0.5 mL of ethanol, the amount of feather fibers was 200 mg of duck feather fibers and the static extraction time was 10 min. The applications to seven kinds of feathers and seven kinds of edible oils all indicated the excellent oil removal efficiencies (>98.0%). Combined with high-performance liquid chromatography-ultraviolet, a quantification method was validated with satisfied linearity (R²≥0.994), accuracy (95.8-114.6%) and precision (≤8.3%) with the limits of detection ranging from 50 to 100 ng/g. The proposed FF-SLE method was simple, effective, convenient, low-cost, green and environmental-friendly for the extraction of analytes from oil samples prior to instrument analysis.

Detection of Synthetic Antioxidants: What Factors Affect the Efficiency in the Chromatographic Analysis and in the Electrochemical Analysis?

Antioxidants are food additives largely employed to inhibit oxidative reactions in foodstuffs rich in oils and fat lipids, extending the shelf life of foodstuffs and inhibiting alterations in color, flavor, smell, and loss of nutritional value. However, various research has demonstrated that the inadequate use of synthetic antioxidants results in environmental and health problems due to the fact that some of these compounds present toxicity, and their presence in the human body, in high concentrations, is related to the development of some cancer types and other diseases. Therefore, the development of analytical methods for identifying and quantifying synthetic antioxidants in foodstuffs is fundamental to quality control and in ensuring consumer food safety. This review describes the recent chromatographic and electrochemical techniques used in the detection of synthetic phenolic antioxidants in foodstuffs, highlighting the main characteristics, advantages and disadvantages of these methods, and specific typical features, which include extraction methods for sample preparation and materials used in the working electrode construction, considering chromatographic and voltammetric methods, since these specific features influence the efficiency in the analysis.

Prenatal Exposure to Emerging Plasticizers and Synthetic Antioxidants and Their Potency to Cross Human Placenta

Gestational exposure to environmental chemicals and subsequent permeation through the placental barrier represents potential health risks to both pregnant women and their fetuses. In the present study, we explored prenatal exposure to a suite of 46 emerging plasticizers and synthetic antioxidants (including five transformation products of 2,6-di-tert-butyl-4-hydroxytoluene, BHT) and their potency to cross human placenta based on a total of 109 maternal and cord serum pairs. Most of these chemicals have rarely or never been investigated for prenatal exposure and associated health risks. Eleven of them exhibited detection frequency greater than 50% in maternal blood, including dibutyl fumarate (DBF), 2,6-di-tert-butylphenol (2,4-DtBP), 1,3-diphenylguanidine (DPG), methyl-2-(benzoyl)benzoate (MBB), triethyl citrate (TEC), BHT, and its five metabolites, with a median concentration from 0.05 to 3.1 ng/mL. The transplacental transfer efficiency (TTE) was determined for selected chemicals with valid measurements in more than 10 maternal/cord blood pairs, and the mean TTEs exhibited a large variation (i.e., 0.29-2.14) between chemicals. The determined TTEs for some of the target chemicals were comparable to the predicted values by our previously proposed models developed from molecular descriptors, indicating that their transplacental transfer potency could be largely affected by physicochemical properties and molecular structures. However, additional biological and physiological factors may influence the potency of environmental chemicals to cross human placenta. Overall, our study findings raise concern on human exposure to an increasing list of plastic additives during critical life stages (e.g., pregnancy) and potential health risks.

Rapid and sensitive detection of tert-butylhydroquinone in soybean oil using a gold-based paper sensor

tert-Butylhydroquinone (TBHQ) residues in foods pose a threat to human health. Therefore, it is necessary to develop a rapid method for TBHQ detection. In this study, a sensitive monoclonal antibody 5C3 (IgG2a subclass) against TBHQ was produced. It possessed a half maximal inhibitory concentration of 7.43 ng mL^-1. A gold nanoparticle-based immunochromatographic assay (ICA) was established for the rapid and sensitive screening of TBHQ in soybean oil. Qualitative analysis results were obtained within 10 min and observed with the naked eye. The visual limit of detection (LOD) was 50 ng g^-1 and the cut-off value was 1000 ng g^-1. A hand-held strip reader was used for quantitative analysis, in which the calculated LOD was defined as 18.68 ng g^-1. The average recoveries of TBHQ ranged from 89.55% ± 2.70% to 100.66% ± 3.02% for soybean oil, with a coefficient of variation of 2.89%-7.05%. Therefore, our developed ICA is a useful tool for the rapid and on-site detection of TBHQ in real food samples.

Alarming impact of the excessive use of tert-butylhydroquinone in food products: A narrative review

Tert-butyl hydroquinone (TBHQ) is a food additive commonly used as a more effective protectant in the food, cosmetic and pharmaceutical industries. However, the long-term exposure to TBHQ at higher doses (0.7 mg/kg) results in substantial danger to public health and brings a series of side effects, including cytotoxic, genotoxic, carcinogenic, and mutagenic effects. As a result, the global burden of chronic diseases has fascinated consumers and governments regarding the safety assessment of food additives. Regarding contradictory reports of various research about the application of food additives, the accurate monitoring of food additives is urgent. Notwithstanding, there are reports of the therapeutic effects of TBHQ under pathologic conditions through activation of nuclear factor erythroid 2-related factor 2. Thus, further investigations are required to investigate the impact of TBHQ on public health and evaluate its mechanism of action on various organs and cells. Therefore, this review aimed to investigate TBHQ safety through an overview of its impacts on different tissues, cells, and biological macromolecules as well as its therapeutic effects under pathologic conditions.

Trace analysis of multiple synthetic phenolic antioxidants in foods by liquid chromatography-tandem mass spectrometry with complementary use of electrospray ionization and atmospheric pressure chemical ionization

This study presented a universal LC-MS/MS method for trace analysis of multiple synthetic phenolic antioxidants (SPAs) in foods by complementary use of electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). The analytes included not only the well-known BHT and BHA but also 18 high molecular weight SPAs. The method utilized APCI to achieve sensitive analysis of BHT, Irganox 1010, Irganox 330, and Irganox 3125 based on the finding that APCI significantly improved the sensitivity of these weakly acidic or slightly polar SPAs, and utilized ESI to obtain sensitive analysis of other SPAs. Additionally, the method avoided background contamination by using effective measures including installation of a trapping column in the LC system. Method performance assessment showed satisfactory sensitivity, linearity, accuracy, and precision for analysis of SPAs in vegetable oil, milk powder, and baby fruit puree. Method application revealed widespread contamination of foods with BHT, Irganox 1010, and Irganox 1076.

Porous carbon derived from ZIF-8 modified molecularly imprinted electrochemical sensor for the detection of tert-butyl hydroquinone (TBHQ) in edible oil

In this manuscript, ZIF-8 derived nanoporous carbon material (ZC) was prepared and used as modification material to construct a molecularly imprinted electrochemical sensor for the direct detection of tert-butyl hydroquinone (TBHQ) in edible oil. Electrochemical characterizations, scanning electron microscopy and X-ray diffraction show that ZC has excellent conductivity, high electrochemical active area and stable porous framework structure. Using TBHQ as template and o-phenylenediamine as functional monomer, the sensor was constructed. Experimental parameters such as the number of polymerization cycle, polymerization speed, and pH of the measured solution, removal and rebinding time were studied. Under optimized conditions, the prepared sensor showed a wider linear range from 1.0 μmol L^-1 to 75.0 μmol L^-1 with the detection limit of 0.42 μmol L^-1 (S/N = 3). Meanwhile, the sensor also expressed good selectivity, repeatability, reproducibility, stability and successfully applied for the determination of TBHQ in real edible oil, giving satisfactory results.

Ultrasensitive detection of cytotoxic food preservative tert-butylhydroquinone using 3D cupric oxide nanoflowers embedded functionalized carbon nanotubes

Accurate detection of cytotoxic food preservative tert-butylhydroquinone (TBHQ) has significant importance in maintaining food quality and safety. TBHQ is a chronic hazard to aquatic life and its use in applications involving direct human exposure and frequent release to environment makes its quantification critical to maintain safety. Hence, we report development of a sensitive electrochemical sensor for TBHQ determination at nanomolar level in commonly used edible oils and water sample. Novel cupric oxide (CuO) decorated amine functionalized carbon nanotubes (NH₂-CNTs) were prepared for development of TBHQ sensor. 3D CuO nanoflowers and NH₂-CNTs were synthesized using hydrothermal and ultrasound-assisted method respectively. Techniques such as SEM, elemental mapping, XRD, FTIR, micro Raman, XPS, EIS, and UV-Visible spectroscopy were taken to affirm significant characterizations of synthesized materials. We have observed outstanding electrocatalytic activity towards TBHQ detection using the sonochemically prepared nanocomposite modified screen printed carbon electrode (SPCE). The proposed sensor exhibited ultra-low detection limit at 3 nM and exceptional sensitivity at 37.7 μA μM^-1 cm^-2. Furthermore, TBHQ sensor showcased outstanding anti-interference, stability, reproducibility, and repeatability. The practical feasibility of TBHQ detection was validated using real sample analysis resulting in excellent recovery in the range 95.90-104.87% and a maximum RSD of mere 2.71%.

Synthetic phenolic antioxidants: Metabolism, hazards and mechanism of action

Synthetic phenolic antioxidants can interact with peroxides produced by food. This paper reviews correlation between BHA, BHT and TBHQ metabolism and harms they cause and provides a theoretical basis for rational use of BHA, BHT and TBHQ in food, and also put some attention on the transformation and metabolic products of PG. We introduce BHA, BHT, TBHQ, PG and their possible metabolic pathways, and discuss possible harms and their specific mechanisms responsible. Excessive addition or incorrect use of synthetic phenolic antioxidants results in carcinogenicity, cytotoxicity, oxidative stress induction and endocrine disrupting effects, which warrant attention. BHA carcinogenicity is related to production of metabolites TBHQ and TQ, and cytotoxic effect of BHA is the main cause of apoptosis induction. BHT carcinogenicity depends on DNA damage degree, and tumour promotion is mainly related to production of quinone methylation metabolites. TBHQ carcinogenicity is related to induction of metabolite TQ and enzyme CYP1A1.

Ultra-sensitive and selective determination of a phenolic food additive using protein capped gold nanoclusters: a dual in-line fluorometric and colorimetric sensing probe

The application of red luminescence BSA-AuNCs towards the selective determination of food additive tert-butylhydroquinone (TBHQ) was demonstrated by both fluorometric and colorimetric methods.

The Sirtuin-1 relied antioxidant and antiaging activity of 5,5'-diferulic acid glucoside esters derived from corn bran by enzymatic method

Maize is the food crop with the highest total output in the world. However, corn bran is only a by-product with low price. The 5,5'-diferulic acid glucoside esters (DFG) were obtained from corn bran using the enzymatic method. DFG showed obvious antioxidant capacity in cell, Caenorhabditis elegans (C. elegans) and in mouse. DFG decreased ROS and MDA content in 500 μM H₂ O₂ stimulated ARPE-19 cells to 48.6% and 32.2%, respectively. DFG decreased ROS content in C. elegans to 49.1% and MDA content in acute ethanol (50%, 12 ml/kg) stimulated mouse to 30.4%. DFG also increased SOD protein content significantly in cell, C. elegans and mouse to 175.5%, 120.1%, and 126.2%, respectively. DFG significantly extended the lifespan of C. elegans both under heat stress and natural situation. The median survival time was prolonged to 133.3% and 116.7%, respectively. This capacity relied on the SIR-2.1 activity. SIR-2.1 is an ortholog of human Sirtuin-1 (SIRT-1). DFG also upregulated SIRT-1 and PCG-1α expression level obviously in H₂ O₂ -stimulated ARPE-19 cells (to 134.4% and 127.1%, respectively) and in acute ethanol stimulated mouse eyes (to 135.1% and 111.5%, respectively) and liver (to 123.3% and 113.6%, respectively). These results indicate that DFG has multiple bioactivities. Our research provides a new application prospect of corn bran. And to our best knowledge, this is the first time, the sirtuins-relied lifespan extension activity of the 5,5'-diferulic acid extracted from corn bran was reported. PRACTICAL APPLICATIONS: The traditional method for extracting diferulic acid from corn bran is to use the strong alkali. Obviously, this is not welcomed by the food industry. We employed the biological enzyme method in a relatively mild pH range during the extraction process. It is more environmentally friendly and more economical. DFG can be added as a raw material for functional foods like yogurt, fruit juice, and cereals. As well, the solid precipitate obtained after extraction can also be used as high-quality dietary fiber to produce functional food. Meanwhile, concerning for the 5,5'-diferulic acid derived from corn bran, the relevant research is still not abundant. And to our best knowledge, we have reported for the first time about the effect of this kinds of diferulic acid on prolonging life span and its SIRT-1-dependent activity. It also provides a new perspective for the study of diferulic acid.

Simultaneous determination of carbendazim and chlorothalonil pesticide residues in peanut oil using excitation-emission matrix fluorescence coupled with three-way calibration method

A novel fluorescence application for simultaneous determination of two common fungicide pesticides (carbendazim and chlorothalonil) in peanut oil is presented. Using the strategy of combining excitation-emission matrix (EEM) fluorescence with three-way calibration methods, the proposed approach successfully achieved quantitative analysis of carbendazim and chlorothalonil pesticide residues in peanut oil, even with highly overlapped spectra. It needs little preparation, using "mathematical separation" instead of "analytical separation" to achieve concentration prediction of target analytes in complex systems. Each analyte was performed using fluorescence spectroscopy after instrument spectral correction and scatter removal. Then the data were modeled with two three-way calibration algorithms, including alternating trilinear decomposition (ATLD) and alternating penalty trilinear decomposition (APTLD). The results indicated that APTLD performed slightly better than ATLD for this system. The carbendazim and chlorothalonil can be recognized simultaneously with the correlation coefficients all above 0.96 between resolved spectra and actual spectra. Satisfactory results have been achieved with the average recoveries (mean ± standard deviation) of carbendazim and chlorothalonil being 100.2 ± 6.7% and 99.7 ± 6.7%, respectively. Moreover, as for carbendazim and chlorothalonil, the sensitivity (SENs) are 1.50 × 10² and 3.80 × 10² mL ng^-1, the limits of detection (LODs) are 11 ng mL^-1 and 4.3 ng mL^-1, the limit of quantitation (LOQ) are 33.33 ng mL^-1 and 13.03 ng mL^-1, respectively. The above results demonstrated that the proposed method is sensitive, fast and accurate for direct quantitative analysis of multiple pesticide residues in complex matrix such as that of peanut oil.

Occurrence of plastic additives in outdoor air particulate matters from two industrial parks of Tarragona, Spain: Human inhalation intake risk assessment

Plastic additives include several kinds of chemicals that are added to the polymer matrix to improve the final product quality and prevent deterioration effects. They are used in a large quantity of materials, so their presence in the environment is expected. This study has developed and validated a method based on gas chromatography-mass spectrometry after pressurised liquid extraction to determine sixteen plastic additives including UV-stabilizers, aromatic and phenolic antioxidants and some of their degradation products in particulate matter (PM₁₀) from outdoor air. Apparent recoveries were above 85% for most of compounds and low detection limits (pg m^-3) were achieved. This is the first study to determine these types of contaminant in the PM₁₀ of outdoor air from two locations surrounded by different industries. Various compounds were found in almost all samples; BHT, BHT-Q, 2,4-DTBP, BHT-CHO, UV320, UV328, Irgafos168 and Iragonx1076, with concentrations ranging from < MQL to 2860 pg m^-3. Estimated daily intakes (EDIs) via ambient inhalation were calculated for each polymer additive and for different subpopulation groups classified by age. Two possible exposure scenarios (low, based on geometric mean, and high, 95th percentile) were simulated, and 0.51 ng kg_bw^-1 day^-1 was the EDI in the worst case scenario for children.

Determination of the antioxidant propyl gallate in meat by using a screen-printed electrode modified with CoSe2 nanoparticles and reduced graphene oxide

A voltammetric sensor is described for the quantitation of propyl gallate (PG). A screen-printed carbon electrode (SPCE) was modified with reduced graphene sheets that were decorated with cobalt diselenide nanoparticles (CoSe₂@rGO). The material was hydrothermally prepared and characterized by several spectroscopic techniques. The modified SPCE displays excellent electrocatalytic ability towards PG. Differential pulse voltammetry, with a peak voltage at 0.34 V (vs. Ag/AgCl) has a sensitivity of 12.84 μA·μM^-1·cm^-2 and a detection limit as low as 16 nM. The method is reproducible, selective, and practical. This method was applied to the determination of PG in spiked meat samples, and the result showed an adequate recovery. Graphical abstract Schematic of a new method for fast and sensitive electrochemical determination of the food additive propyl gallate in meat.

Enzymatic biosensor of horseradish peroxidase immobilized on Au-Pt nanotube/Au-graphene for the simultaneous determination of antioxidants

A new electrochemical method has been proposed for the simultaneous determination of butylated hydroxyanisole (BHA) and propyl gallate (PG) in food matrices based on enzymatic biosensors. Spiny Au-Pt nanotubes (SAP NTs) was first synthesized and demonstrated to exhibit intrinsic peroxidase and catalase-like activity. The structure of SAP NTs provides large surface area and favorable medium for electron transfer, on which HRP were immobilized and acted as enzymatic biosensor for the simultaneous detection of BHA and PG. The results revealed that BHA and PG both have well-defined oxidation waves with peak potentials of 624 and 655 mV, respectively. Under the optimal conditions, the method behaved satisfactory analytical performance towards BHA and PG with a wide linear range of 0.3-50 mg L(-1) and 0.1-100 mg L(-1), as well as a detection limit of 0.046 mg L(-1) and 0.024 mg L(-1) (3σ/slope), respectively. Besides, the proposed method exhibits good sensitivity, stability and reproducibility, providing an alternative to fabricate electrode and construct sensitive biosensors.

Highly Sensitive and Selective Determination of Tertiary Butylhydroquinone in Edible Oils by Competitive Reaction Induced "On-Off-On" Fluorescent Switch

As one of most common synthetic phenolic antioxidants, tertiary butylhydroquinone (TBHQ) has received increasing attention due to the potential risk for liver damage and carcinogenesis. Herein, a simple and rapid fluorescent switchable methodology was developed for highly selective and sensitive determination of TBHQ by utilizing the competitive interaction between the photoinduced electron transfer (PET) effect of carbon dots (CDs)/Fe(III) ions and the complexation reaction of TBHQ/Fe(III) ions. This novel fluorescent switchable sensing platform allows determining TBHQ in a wider range from 0.5 to 80 μg mL(-1) with a low detection limit of 0.01 μg mL(-1). Furthermore, high specificity and good accuracy with recoveries ranging from 94.29 to 105.82% in spiked edible oil samples are obtained with the present method, confirming its applicability for the trace detection of TBHQ in a complex food matrix. Thus, the present method provides a novel and effective fluorescent approach for rapid and specific screening of TBHQ in common products, which is beneficial for monitoring and reducing the risk of TBHQ overuse during food storage.

Determination of synthetic phenolic antioxidants in soft drinks by stir-bar sorptive extraction coupled to gas chromatography-mass spectrometry

The synthetic phenolic antioxidants butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and tert-butyl hydroquinone (TBHQ) were pre-concentrated by stir-bar sorptive extraction and thermally desorbed (SBSE-TD) before analysis by GC-MS. Several parameters affecting the derivatisation step and both SBSE extraction and thermal desorption were carefully optimised. When the analyses of BHA and TBHQ in their acetylated, silylated and underivatised forms were compared, the best results were obtained when the in-situ derivatisation procedure with acetic anhydride was employed. Quantification was carried out using carvacrol as the internal standard, providing quantification limits of between 0.11 and 0.15 ng ml(-1), depending on the compound. Recovery assays for samples spiked at two concentration levels, 1 and 5 ng ml(-1), provided recoveries in the 81-117% range. The proposed method was applied in the analysis canned soft drinks and the analytes were found in five of the 10 samples analysed.

Intercalation binding of food antioxidant butylated hydroxyanisole to calf thymus DNA

The binding properties of food antioxidant butylated hydroxyanisole (BHA) associated with calf thymus DNA (ctDNA) in physiological buffer (pH 7.4) were investigated. Experimental results based on fluorescence, UV-vis absorption, circular dichroism (CD), viscosity measurements and autodocking techniques confirmed the intercalation binding between BHA and ctDNA. The changes in Fourier transform infrared spectra of ctDNA induced by BHA suggested that BHA was more prone to bind to G-C rich region of ctDNA, which was further ascertained with the molecular docking studies. Analysis of the CD spectra indicated that this binding interaction led to a transformation from B-like DNA structure toward A-like conformation. The complexation of BHA with ctDNA was driven mainly by hydrogen bonds and hydrophobic forces. The binding constants of the BHA-ctDNA complex were calculated to be 2.03 × 10(4), 1.92 × 10(4) and 1.59 × 10(4)L mol(-1) at 298, 304 and 310 K, respectively. Gel electrophoresis results suggested that intercalated BHA molecules did not significantly affect plasmid DNA. Moreover, the concentration profiles and the spectra for the three reaction components (BHA, ctDNA, and BHA-ctDNA complex) of the system by resolving the augmented UV-vis spectral data matrix with the use of multivariate curve resolution-alternating least squares approach provided quantitative data to estimate the progress of BHA-ctDNA interaction. This study is expected to provide new insights into the mechanism of interaction between BHA and ctDNA.