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An ultrasensitive biosensing platform for DNA and ochratoxin A (OTA) detection is constructed based on the luminescence quenching ability of fullerenol quantum dots (FOQDs) for the first time. As the surface of FOQDs is largely covered by hydroxyl groups, stable colloidal suspension of FOQDS in aqueous solution can be obtained, which is very advantageous for application in biosensing compared to nano-C60. FOQDs can effectively quench the fluorescence of dyes with different emission wavelengths that are tagged to bioprobes to an extent of more than 87% in aqueous buffer solution through a PET mechanism. Moreover, the nonspecific quenching of the fluorescent dyes (not bound to bioprobes) caused by FOQDs is negligible, so the background signal is extremely low which is beneficial for improving the detection sensitivity. Based on the π–π stacking interaction between FOQDs and bioprobes, such as single-stranded (ss) DNA and aptamers, a nucleic acid assay with a detection of limit of 15 pM and a highly sensitive OTA assay with a detection limit of 5 pg mL−1 in grape juice samples are developed through the simple “mix and measure” protocol based on luminescence quenching-and-recovery. This is the first demonstration of constructing biosensors utilizing the luminescence quenching ability of FOQDs through a PET mechanism, and the pronounced assay performance implies the promising potential of FOQDs in biosensing.

Background Edible oils play a vital role in our daily life, which provide human beings with energy, essential fatty acids and nutrients. The quality of edible oils can be dependent on the quality of the oilseeds they originate from, and their adulteration during processing. In recent years, near infrared spectroscopy was widely used in the rapid assessment of quality of oilseeds and edible oils. However, to the best of our knowledge, a comprehensive review on near infrared spectroscopy for the quality of oilseeds remains to be published. Scope and approach The applications of near infrared spectroscopy in the quality of oilseeds and edible oils have been emphasized in this review. This article briefly summarizes the basic knowledge of near infrared spectroscopy. In addition, we highlight the application of this technique on the detection of physicochemical properties and quality, specific nutrient components, authentication, and geographical origin traceability of oilseeds and edible oils. Moreover, the application of near infrared hyperspectral imaging technology in oilseeds has been addressed. Key findings and conclusions: Near infrared spectroscopy possesses the advantages of rapid, green and low-cost analysis. Meanwhile, it is also a nondestructive method and therefore suitable to quality analysis of oilseeds in agricultural sciences. It can be used to detect macro nutrients in oilseeds and edible oils by combining NIR and advanced chemometrics. In the future, NIR could be applied in the rapid detection and online detection of hazardous substances and nutrients in oilseeds by developing the new instrument and chemometric methods.

Volatile flavor components are critical to edible oils and influence consumption choice. Meanwhile, volatile organic compounds (VOCs) in edible oils are also potential biomarkers to detect adulterated products. However, VOCs are usually complex, unstable, and easily influenced by oil processing and even analysis conditions. Here, we report headspace solid-phase microextraction for comprehensive two-dimensional gas chromatography mass spectrometric analysis of VOCs in edible oils as being optimized and validated using central composite design (CCD). The results indicated that the optimal extraction conditions are as follows: SPE column of divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS), equilibration time of 10.3 min, and extraction time of 19.6 min at 120 °C. This method could analyze edible oils to identify characteristic flavor components. As a result, 25 VOC tags were identified and used to characterize soybean oils. Chemometric methods were used to discriminate the authentic sesame oils from those adulterated with soybean oil. The results indicated that this method is an effective approach to measure VOCs in edible oils; such measurements can report counterfeit products.

Rapeseed (Brassica napus L.) is rich in phenols, vitamins, carotenoids, and mineral elements, such as selenium. Additionally, it contains the active ingredients sulforaphane and indole-3-carbinol, which have been demonstrated to have pharmacological effects. In this study, sulforaphane and indole-3-carbinol were extracted and quantified from rapeseeds using quick, easy, cheap, effective, rugged and safe (QuEChERS) method coupled with ultra high performance liquid chromarography tandem mass spectrometry (UHPLC-MS/MS). The major parameters for extraction and purification efficiency were optimized, including the hydrolysis reaction, extraction condition and type and amount of purification adsorbents. The limit of detection (LOD) and the limit of quantification (LOQ) for sulforaphane were 0.05 &mu, g/kg and 0.15 &mu, g/kg, and for indole-3-carbinol were 5 &mu, g/kg and 15 &mu, g/kg, respectively. The developed method was used to successfully analyze fifty rapeseed samples. The QuEChERS coupled with UHPLC-MS/MS simultaneously detect sulforaphane and indole-3-carbinol in vegetable matrix and evaluate the quality and nutrition of rapeseed samples.

Food adulteration is a challenge faced by consumers and researchers. Due to DNA fragmentation during oil processing, it is necessary to discover metabolic markers alternative to DNA for adulteration detection of edible oils. However, the contents of metabolic markers vary in response to various factors, such as plant species, varieties, geographical origin, climate, and cultivation measures. Thus, it is difficult to identify a universal marker for all adulterants that may be present in some authentic samples. Currently, the specificity and selectivity of metabolic biomarkers are difficult to validate. Therefore, this study developed a screening strategy based on plant metabolic networks by developing a targeted analytical method for 56 metabolites in a metabolic network, using liquid/liquid extraction–liquid chromatography–tandem mass spectrometry (LC-MS/MS). We identified a chain of 11 metabolites that were related to isoflavonoid biosynthesis, which were detected in soybean oils but not rapeseed oils. Through multiple-marker mutual validation, these metabolites can be used as species-specific universal markers to differentiate soybean oil from rapeseed oil. Moreover, this method provides a model for screening characteristic markers of other edible vegetable oils and foods.

Aflatoxins, highly toxic and carcinogenic to humans, are synthesized via multiple intermediates by a complex pathway in several Aspergilli, including Aspergillus flavus. Few analytical methods are available for monitoring the changes in metabolite profiles of the aflatoxin biosynthesis pathway under different growth and environmental conditions. In the present study, we developed by a D-optimal mixture design a solvent system, methanol/dichloromethane/ethyl acetate/formic acid (0.36/0.31/0.32/0.01), that was suitable for extracting the pathway metabolites. The matrix effect from dilution of cell extracts was negligible. To facilitate the identification of these metabolites, we constructed a fragmentation ion library. We further employed liquid chromatography coupled with high-resolution mass spectroscopy (UHPLC-HRMS) for simultaneous quantification of the metabolites. The limit of detection (LOD) and limit of quantitation (LOQ) were 0.002-0.016 and 0.008-0.05 μg/kg, respectively. The spiked recovery rates ranged from 81.3 to 100.3% with intraday and interday precision less than 7.6%. Using the method developed to investigate the time-course aflatoxin biosynthesis, we found that precursors, including several possible toxins (with a carcinogenic group similar to aflatoxin B1), occurred together with aflatoxin, and that production increased rapidly at the early growth stage, peaked on day four, and then decreased substantially. The maximum production of aflatoxin B1 and aflatoxin B2 occurred 1 day later. Moreover, the dominant branch pathway was the one for aflatoxin B1 formation. We revealed that the antiaflatoxigenicity mechanism of Leclercia adecarboxylata WT16 was associated with a factor upstream of the aflatoxin biosynthesis pathway. The design strategies can be applied to characterize or detect other secondary metabolites to provide a snapshot of the dynamic changes during their biosynthesis.

In natural science, models could grant new insights into phenomena or scientific problems which are hard to be observed or otherwise explained to overcome the limitations of human beings. Routinely, scientists strive to develop new methods for data acquisition, preprocessing, variable selection, modeling and valuation with the help of statistics and machine learning theories. Theoretically, the aim of these methods is global or local optimization in the space of variables and linear/nonlinear combinations for classification or regression. However, the relationships between responses and features are often complex and therefore sometimes far from linear or fixed nonlinear model. In this study, we proposed the relational variable (e.g. ratio between two variables) for more accurate prediction performance of models and illustrated its application on three classic data. We found that the selected relational variables could significantly improve the accuracy of prediction. The software was complemented on the MATLAB R2015a platform in Windows Server 2012 R2 standard. The Matlab codes used in this study are publicly available at http://www.libpls.net .

Delamination of layer semiconductor materials into two-dimensional sheets can bring superior properties such as surface area, intrinsic carrier mobility and band structure. In this study, inerratic nanosized graphitic carbon nitride (g-C3N4) sheets with the lateral size of approximately 100 ± 50 nm are conveniently fabricated by ultrasonic exfoliation of bulk g-C3N4 that derived from thermolysis of dicyandiamide after recrystallization. The nanosized g-C3N4 sheets exhibit excellently higher photocatalytic performance toward aflatoxin B1 (AFB1) degradation under visible light than that of bulk g-C3N4. And the enhanced photocatalytic mechanisms are mainly due to the better photogenerated charges separation and larger surface area of nanosized g-C3N4 sheets, which are systematically confirmed by physicochemical and photoelectric characterization. Through identification of products structure, it is found that the initial photodegradation intermediate (C17H14O7) or main products (C14H16O4 and C12H10O4) of AFB1 after 2 h irradiation over bulk g-C3N4 and nanosized g-C3N4 sheets are different, which may be attributed to the photoactivities and number of active groups from both catalysts during photoreaction. Therefore, this work may provide referential information for preparation of inerratic nanosized sheets and understand the related photodegradation mechanism of aflatoxin B1.

A method based on comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOF/MS) was developed to analyze steroidal compounds in vegetable oils, which could provide better separation and higher sensitivity than conventional one dimensional gas chromatography, and allowed determination of 31 sterols and triterpene alcohols in one injection. Furthermore, the approach also permitted separation and detection of small amounts of other compounds (may be steroidal compounds whose molecular structures have not been confirmed), which were obscured in the lower-resolution single-column technique. With the help of the GC × GC system, a more elaborate and complete information regarding the distributions and concentrations of free phytosterols and triterpene alcohols in safflower seed oil, soybean oil, rapeseed oil, sunflower seed oil and peanut oil were obtained. The proposed method could potentially open a new opportunity for the more in-depth knowledge of the steroidal compounds of vegetable oils.

Geometric architecture of composite photocatalytic system creates a favorable chance for enhanced photocatalytic activity, which is a challenging and rewarding direction in this area. Here, a novel and highly efficient three-components composite consisting of dispersive WO3 nanowires, g-C3N4 nanosheets and RGO as solid electron mediator was successfully designed, synthesized and characterized. The WO3/RGO/g-C3N4 composite exhibited markedly enhanced activity for the photocatalytic degradation of aflatoxin B1 under visible-light irradiation compared with single and binary catalysts. It was found that the synergistic effects coexisted in this ternary composites that depended on the geometric architecture and interface combination of components. The Z-scheme system formed when RGO was as an interlayer between WO3 and g-C3N4, while the mechanism was the heterojunction-type in absence of RGO. It was found that the O2−, h+ and OH were main active radicals during photodegradation of AFB1 over ternary composites, which was proved by the radical trapping tests and ESR detection. Finally, a probable enhanced photocatalytic degradation mechanism of ternary composites and the degradation products were also proposed. This work may not only provide beneficial information to design and synthesis of effective composites system, but also present a new way to remove the refractory natural pollutant.

Aspergillus flavus can cause crop loss and produce mycotoxin that bring serious threats to human health. The large usage of chemical pesticides or fungicides might cause environmental problems and fungal resistance. Therefore, developing the novel, low possibility of resistance and pro-environment way to control and reduce this fungi is meaningful. Herein, an efficient, environmental-friendly and photocatalytic method to disinfect Aspergillus flavus was demonstrated on magnetic and Z-schematic composites. The composites were composed of rhombic NiFe2O4 nanosheets and g-C3N4 nanosized sheets, and 0.2 g-C3N4/NiFe2O4 (mass ratio) showed the excellent activity with above 90% disinfection rate under 90 min visible light irradiation. The efficient disinfection activities were ascribed to the favorable charges separation, well photoelectric properties and suitable band structure. It was found that the •O2− and •OH were the main active radical species in photocatalytic disinfection. The attack of these species could cause the destruction of fungal cell structure and the leakage of intracellular contents as proved by the fluorescence staining of spores, biological scanning electron microscope and the detection of extracellular protein and DNA. Moreover, the composites also showed high photocatalytic disinfection activity of Aspergillus flavus on peanuts, which can reduce aflatoxin B1 from 315.21 µg kg−1 to 18.50 µg kg−1. This efficient method might be considered as a potential way to control the contamination of Aspergillus flavus, and as a reference to the mitigation of other pathogenic fungi in future.

To develop effective adulteration detection methods is essential as food quality and safety draw particular concern all over the world. In this study, Monte Carlo one-class partial least squares (MCOCPLS) was proposed and employed as a novel one class classification model for authentication identification by using virgin olive oil (VOO) as an example. Monte Carlo sampling was proposed for selecting variable subspace to improve the performance of one-class partial least squares (OCPLS) classifier. MCOCPLS was used to establish a one-class model, the performance of which was validated by an independent test set consisting of 5000 adulterated oils simulated by the Monte Carlo method. The prediction for the best model of MCOCPLS reaches a correct rate of 99.10%. Moreover, authentic VOOs were analyzed and assessed for the adulteration risk. In conclusion, the proposed MCOCPLS method could be used to effectively detect olive oils adulterated with other vegetable oils at a concentration of as low as 3%. Therefore, MCOCPLS provides an effective tool and new insights in adulteration detection for edible oils and other foods.

Multivariate and untargeted adulterations are real cases of oil adulteration in practice. In this study, one-class support vector machine (OC-SVM) was used to build the model for detecting multivariate and untargeted adulterations of sesame oil. The predictive model was subsequently validated by an independent test set. The results indicated that the OC-SVM model could completely detect the adulterated oils. Moreover, oils adulterated with different levels of mixed edible oils were simulated by Monte Carlo method and employed to determine the lowest adulteration level of the predictive model. Compared with earlier studies, the OC-SVM model proposed for sesame oil in this study is more robust to detect untargeted and multivariate adulteration.

Sesame is a nutritional agricultural product with medicinal properties. Accurate determination of micronutrients is important for the improvement of sesame quality and nutrition assessments. Our previous study showed that 10 antioxidants&mdash, d-homoproline, vitamin B2, coniferyl aldehyde, hesperidin, phloretin, N-acetyl-l-leucine, l-hyoscyamine, ferulic acid, 5-methoxypsoralen, and 8-methoxypsoralen&mdash, in sesame were potential characteristic nutrients in sesame. Herein, simultaneous detection of 10 different types of antioxidants was developed by using ultrasound-assisted extraction coupled with liquid chromatography-tandem mass spectrometry (UAE-LC-MS/MS) with the help of response surface methodology. The significant variables and levels were screened and optimized by combining the single factor experiment, Plackett&ndash, Burman test, and Box&ndash, Behnken design. The optimal conditions for extraction of target antioxidants in sesame were methanol solution of 75.0%, liquid-to-material ratio of 20:1 (mL/g), extraction temperature of 50 &deg, C, extraction power of 410.0 W, extraction time of 65 min. The total yield of targets was 21.74 &mu, g/g under the optimized conditions. The mobile phase used was 0.1% formic acid in acetonitrile and 0.1% formic acid in water, and the column was a Thermo Syncronis C18 reverse phase column (100 mm &times, 2.1 mm, 3 &mu, m). All targets required only one injection and could be quickly separated and assayed within 7 min. The limits of detection and limits of quantification for these 10 nutritional compounds ranged from 0.01 to 0.11 &micro, g/kg and from 0.04 to 0.34 &micro, g/kg, respectively. The validation results indicated that the method had reasonable linearity (R2 &ge, 0.9990), good recoveries (71.1%&ndash, 118.3%), satisfactory intra-day precision (&le, 9.6%) and inter-day precision (&le, 12.9%), and negligible matrix effects (&le, 13.8%). This simultaneous quantification method was accurate, fast, and robust for the assessment of sesame nutrition.

Rapeseed is an important oilseed with proper fatty acid composition and abundant bioactive components. Canada and China are the two major rapeseed-producing countries all over the world. Meanwhile, Canada and Mongolia are major importers of rapeseed due to the great demand for rapeseed in China. To investigate the metabolites in rapeseeds from three countries, ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS)-based metabolomics was employed to analyze rapeseeds from China, Canada, and Mongolia. As results, 67, 53, and 68 metabolites showed significant differences between Chinese and Canadian, Chinese and Mongolian, and Canadian and Mongolian rapeseeds, respectively. Differential metabolites were mainly distributed in the metabolic pathways including phenylpropanoid biosynthesis, flavone and flavonol biosynthesis, and ubiquinone and other terpenoid-quinone biosynthesis. Among the differential metabolites, contents of sinapate and sinapine were higher in Chinese rapeseeds, while the contents of brassicasterol, stigmasterol, and campestanol were higher in Canadian rapeseeds. These findings might provide insight into the metabolic characteristics of rapeseeds from three countries to guide processing and consumption of the products of rapeseed.

High complexity of identification for non-target triacylglycerols (TAGs) is a major challenge in lipidomics analysis. To identify non-target TAGs, a powerful tool named accurate MS n spectrometry generating so-called ion trees is used. In this paper, we presented a technique for efficient structural elucidation of TAGs on MS n spectral trees produced by LTQ Orbitrap MS n , which was implemented as an open source software package, or TIT. The TIT software was used to support automatic annotation of non-target TAGs on MS n ion trees from a self-built fragment ion database. This database includes 19108 simulate TAG molecules from a random combination of fatty acids and corresponding 500582 self-built multistage fragment ions (MS ≤ 3). Our software can identify TAGs using a “stage-by-stage elimination” strategy. By utilizing the MS 1 accurate mass and referenced RKMD, the TIT software can discriminate unique elemental composition candidates. The regiospecific isomers of fatty acyl chains will be distinguished using MS 2 and MS 3 fragment spectra. We applied the algorithm to the selection of 45 TAG standards and demonstrated that the molecular ions could be 100% correctly assigned. Therefore, the TIT software could be applied to TAG identification in complex biological samples such as mouse plasma extracts.

A novel magnetic carboxylated multi-walled carbon nanotubes (c-MWCNT-MNPs) was proposed for magnetic solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry to determine phenolic compounds in sesame oil. In this study, c-MWCNT-MNPs were acquired by simply dispersing Fe3O4 magnetic nanoparticles into carboxylated multi-walled carbon nanotubes. The major parameters affecting extraction efficiency were optimized, including the type and volume of desorption solvents, extraction and desorption time, washing solution, and sorbent amount. The limit of quantifications and limit of detections were from 0.03μg/kg to 43.00μg/kg and from 0.01μg/kg to 13.60μg/kg, respectively. The recoveries of phenolic compounds in vegetable oils were in the range of 83.8-125.9% with inter-day and intra-day precisions of less than 13.2%. It was confirmed that this method was simple, rapid and reliable with an excellent potential for routine analysis of phenolic compounds in oil samples.

To monitor capsaicinoids in serum on-site, three new monoclonal antibodies (mAbs) were firstly proposed using a conjugate of 4-[(4-hydroxy-3-methoxybenzyl) amino]-4-oxobutanoic acid as the immunogen. Among them, the YQQD8 mAb showed the highest sensitivity and cross-reactivity to major capsaicinoids, such as capsaicin, dihydrocapsaicin and N-vanillylnonanamide. A competitive indirect enzyme-linked immunosorbent assay (icELISA) and a time-resolved fluorescent immunochromatographic assay (TRFICA) were established based on this mAb. The linear range was 1.1-27.0ngmL(-1) for icELISA and 1.9-62.5ngmL(-1) for TRFICA and the limit of detection (LOD) of TRFICA was 1.5ngmL(-1). To decrease the interference of sample components and increase accuracy, serum samples were diluted four times before assays. As a result, the linear range of serum samples was 4.6-107.9ngmL(-1) for icELISA and 7.6-250.0ngmL(-1) for TRFICA. Both icELISA and TRFICA showed good recoveries (91.0-112.8% for icELISA and 87.6-111.5% for TRFICA) and concordant results in spiked experiments. Overall, this is the first report of immunoassay based on the mAbs for quantitative determination of major capsaicinoids, and the results demonstrate that both methods can meet the demands of rapid on-site assay for capsaicinoids in serum samples.

Highly predictive multivariate calibration model depends on samples in training set. In this study, we introduced an outlier detection method and developed its improvement for shorter run time. Improved Monte-Carlo outlier detection (IMCOD) was proposed to establish cross-prediction models for determining normal samples, which were subsequently used to analyze the distribution of prediction errors for all of dubious samples together. Four real datasets were employed to illustrate and validate the performance of IMCOD. After sample selection for training set of NIR of soy flour samples, the Root Mean Square Error of Prediction (RMSEP) of PLS model decreased from 1.4811 to 0.7650. This method benefits the establishment of a good model for QSAR and NIR datasets.

Two nanoprobes based on gold nanoparticles (AuNPs) and magnetic nanoparticles (MNPs) were synthesized, respectively. A double- nanoprobe based immunoassay with sensitivity, rapidity, and reproducibility was developed for the determination of phenanthrene (Phe) and related low-mass polycyclic aromatic hydrocarbons (PAHs) in water samples. The AuNPs probe was used as signal amplification probe, which can improve the sensitivity of the immunoassay. The MNPs probe was used as immobilization of Phe, which can lead to speed up reaction of antigen-antibody by the suspension property and dispersed nature. The linear range and the limit of detection (LOD) were 0.14–6.55 ng/mL and 0.08 ng/mL, respectively. Compared with the traditional ELISA, the sensitivity of the double-probe based immunoassay was improved about 30 times and the time for determination was shorten 104 min. The recoveries of Phe and related low-mas PAHs from tap water, contaminated water and river water were 90.5–109.8%, 91.2–108.0% and 93.0–107.8%, respectively. The correlation coefficient of the results between the developed immunoassay and GC–MS/MS was 0.9977. The developed double- nanoprobe based immunoassay was sensitive, rapid and good reproducibility for the determination of Phe and related low-mas PAHs in environmental water.

Vitamin K1 is one of the important hydrophobic vitamins in fat-containing foods. Traditionally, lipase is employed in the determination of vitamin K1 to remove the lipids, which makes the detection complex, time-consuming, and insensitive. In this study, the determination of vitamin K1 in fat-containing foods was developed based on ultrasound-assisted extraction (UAE), solid-phase extraction (SPE) combined with liquid chromatography&ndash, tandem mass spectrometry (LC-MS/MS). The optimal conditions for extraction of vitamin K1 were material&ndash, liquid ratio of 1:70 (g/mL), extraction temperature of 50 &deg, C, extraction power of 700 W, extraction time of 50 min, material-wash fluid ratio of 1:60 (g/mL), and 8 mL of hexane/anhydrous ether (97:3, v/v) as the elution solvent. Then, vitamin K1 was analyzed on a ZORBAX SB-C18 column (50 mm &times, 2.1 mm, 1.8 &mu, m) by gradient elution with water (0.01% formic acid) and methanol (0.01 formic acid + 2.5 mmol/L ammonium formate) as the mobile phase. The limit of detection (LOD) and limit of quantification (LOQ) were 0.05 and 0.16 &mu, g/kg, respectively. Calibration curve was linear over the range of 10&ndash, 500 ng/mL (R2 &gt, 0.9988). The recoveries at three spiked levels were between 80.9% and 119.1%. The validation and application indicated that the proposed method was simple and sensitive in determination of vitamin K1 in fat-containing foods.

A method was developed to simultaneously determine eight bioactive compounds in edible oil based on ultrasound-assisted saponification, liquid-liquid extraction and liquid chromatography coupled with tandem mass spectrometry. Central composite design was employed to optimize ultrasonic temperature and time of saponification. Sample treatment was conducted by ultrasound-assisted saponification at temperature of 75 °C for 40 min. Limits of detection and limits of quantification ranged from 2.0 to 3.2 and from 6.1 to 10.0 ng/mL, respectively. Linear correlations were obtained (R2 > 0.99) and the recoveries at three spiked levels were between 81.7% and 112.0%. This method was employed to determine eight compounds in camellia oils and olive oils. As results, the contents of stigmasterol, δ-tocopherol, γ-tocopherol, β-carotene and lutein in camellia oils were significantly higher than those in olive oils (p

Adulteration of edible oils has attracted attention from more researchers and consumers in recent years. Complex multispecies adulteration is a commonly used strategy to mask the traditional adulteration detection methods. Most of the researchers were only concerned about single targeted adulterants, however, it was difficult to identify complex multispecies adulteration or untargeted adulterants. To detect adulteration of edible oil, identification of characteristic markers of adulterants was proposed to be an effective method, which could provide a solution for multispecies adulteration detection. In this study, a simple method of multispecies adulteration detection for camellia oil (adulterated with soybean oil, peanut oil, rapeseed oil) was developed by quantifying chemical markers including four isoflavones, trans-resveratrol and sinapic acid, which used liquid chromatography tandem mass spectrometry (LC-MS/MS) combined with solid phase extraction (SPE). In commercial camellia oil, only two of them were detected of daidzin with the average content of 0.06 ng/g while other markers were absent. The developed method was highly sensitive as the limits of detection (LODs) ranged from 0.02 ng/mL to 0.16 ng/mL and the mean recoveries ranged from 79.7% to 113.5%, indicating that this method was reliable to detect potential characteristic markers in edible oils. Six target compounds for pure camellia oils, soybean oils, peanut oils and rapeseed oils had been analyzed to get the results. The validation results indicated that this simple and rapid method was successfully employed to determine multispecies adulteration of camellia oil adulterated with soybean, peanut and rapeseed oils.

In this study, magnetic graphene nanocomposite Fe3O4/rGO was synthesized by facile one-pot solvothermal method. The nanocomposite was successfully used as magnetic solid phase extraction (MSPE) adsorbents for the determination of aflatoxins in edible vegetable oils through the &pi, &ndash, &pi, stacking interactions. MSPE parameters including the amount of adsorbents, extraction and desorption time, washing conditions, and the type and volume of desorption solvent were optimized. Under optimal conditions, good linear relationships were achieved. Limits of detection of this method were as low as 0.02 &micro, g/kg and 0.01 &micro, g/kg for aflatoxin B1 and B2, respectively. Finally, the magnetic graphene nanocomposite was successfully applied to aflatoxin analysis in vegetable oils. The results indicated that the recoveries of the B-group aflatoxins ranged from 80.4% to 106.0%, whereas the relative standard deviations (RSDs) were less than 8.1%. Owing to the simplicity, rapidity and efficiency, Fe3O4/rGO magnetic solid phase extraction coupled with high-performance liquid chromatography fluorescence with post-column photochemical derivatization (Fe3O4/rGO MSPE-HPLC-PCD-FLD) is a promising analytical method for routine and accurate determination of aflatoxins in lipid matrices.

Capsaicin and dihydrocapsaicin were selected as adulteration markers to authenticate vegetable oils. In this study, a method of immunoaffinity chromatography (IAC) combined with liquid chromatography-tandem mass spectrometry was established for the determination of capsaicin and dihydrocapsaicin in vegetable oils. In this method, immunosorbents were obtained by covalently coupling highly specific capsaicinoid polyclonal antibodieswith CNBr-activated Sepharose 4B, and then packed into a polyethylene column. In this paper, the major parameters affecting IAC extraction efficiency, including loading, washing and eluting conditions, were also investigated. The IAC column displayed high selectivity for capsaicin and dihydrocapsaicin with the maximum capacity of 240 ng. The limit of detection (LOD) and limit of quantification (LOQ) for capsaicin were calculated as 0.02 and 0.08 μg kg−1, and for dihydrocapsaicin were 0.03 and 0.10 μg kg−1. The recoveries of capsaicin and dihydrocapsaicin in oil samples were in the range of 87.3–95.2% with the relative standard deviation (RSD) of less than 6.1%. The results indicated that capsaicinoid compounds could not be found in edible vegetable oils. Therefore, the proposed method is simple, reliable and adequate for routine monitoring of capsaicinoid compounds in vegetable oils and has an excellent potential for detection of adulteration with inedible waste oil.

A simple and rapid detection technology was proposed based on ion mobility spectrometry (IMS) fingerprints to determine potential adulteration of sesame oil. Oil samples were diluted by n-hexane and analyzed by IMS for 20s. Then, chemometric methods were employed to establish discriminant models for sesame oils and four other edible oils, pure and adulterated sesame oils, and pure and counterfeit sesame oils, respectively. Finally, Random Forests (RF) classification model could correctly classify all five types of edible oils. The detection results indicated that the discriminant models built by recursive support vector machine (R-SVM) method could identify adulterated sesame oil samples (⩾ 10%) with an accuracy value of 94.2%. Therefore, IMS was shown to be an effective method to detect the adulterated sesame oils. Meanwhile, IMS fingerprints work well to detect the counterfeit sesame oils produced by adding sesame oil essence into cheaper edible oils.

Aflatoxins, a group of extremely hazardous compounds because of their genotoxicity and carcinogenicity to human and animals, are commonly found in many tropical and subtropical regions. Ultraviolet (UV) irradiation is proven to be an effective method to reduce or detoxify aflatoxins. However, the degradation products of aflatoxins under UV irradiation and their safety or toxicity have not been clear in practical production such as edible oil industry. In this study, the degradation products of aflatoxin B₁ (AFB₁) in peanut oil were analyzed by Ultra Performance Liquid Chromatograph-Thermo Quadrupole Exactive Focus mass spectrometry/mass spectrometry (UPLC-TQEF-MS/MS). The high-resolution mass spectra reflected that two main products were formed after the modification of a double bond in the terminal furan ring and the fracture of the lactone ring, while the small molecules especially nitrogen-containing compound may have participated in the photochemical reaction. According to the above results, the possible photodegradation pathway of AFB₁ in peanut oil is proposed. Moreover, the human embryo hepatocytes viability assay indicated that the cell toxicity of degradation products after UV irradiation was much lower than that of AFB₁, which could be attributed to the breakage of toxicological sites. These findings can provide new information for metabolic pathways and the hazard assessment of AFB₁ using UV detoxification.