Simultaneous detection of 12 mycotoxins in cereals using RP-HPLC-PDA-FLD with PHRED and a post-column derivatization system

High performance liquid chromatography coupled with post - Column derivatization methods in food analysis: Chemistries and applications in the last two decades

High performance liquid chromatography coupled with post-column derivatization is used for increasing the sensitivity and selectivity of the desirable analytes after the chromatographic separation. The transformation of the analytes can be conducted through the addition of a suitable reagent in the eluted stream or the ultraviolet irradiation of the eluted analytes, forming detectable derivatives for ultraviolet or fluorescence detectors. This review focuses on the developed methods using high performance liquid chromatography coupled with post-column derivatization for the determination of substances in food samples during the last two decades. The significance of the determination of each analyte in foods and the existing guidelines in each case are discussed. Preparation of the samples and the analytical methods are commented. For each analyte, official methods and commercially available systems and reagents are mentioned, as well.

Development of an Immunofluorescent Capillary Sensor for the Detection of Zearalenone Mycotoxin

A capillary-based immunofluorescence sensor was developed and incorporated in a flow injection analysis system. The light-guiding capillary was illuminated axially by a 473 nm/5 mW solid state laser through a tailored optofluidic connector. High sensitivity of the system was achieved by efficiently collecting and detecting the non-guided fluorescence signal scattered out along the wall of the capillary. The excitation was highly suppressed with bandpass and dichroic filters by simultaneously exploiting the guiding effect inside the capillary. The glass capillary used as a measuring cell was silanized in liquid phase by 3-aminopropyltriethoxysilane (APTS), and the biomolecules were immobilized using glutaraldehyde inside the capillary. The applicability of the developed system was tested with a bovine serum albumin (BSA)-anti-BSA-IgG model-molecule pair, using a fluorescently labeled secondary antibody. Based on the results of the BSA-anti-BSA experiments, a similar setup using a primary antibody specific for zearalenone (ZON) was established, and a competitive fluorescence measurement system was developed for quantitative determination of ZON. For the measurements, 20 µg/mL ZON-BSA conjugate was immobilized in the capillary, and a 1:2500 dilution of the primary antibody stock solution and a 2 µg/mL secondary antibody solution were set. The developed capillary-based immunosensor allowed a limit of detection (LOD) of 0.003 ng/mL and a limit of quantification (LOQ) of 0.007 ng/mL for ZON in the competitive immunosensor setup, with a dynamic detection range of 0.01-10 ng/mL ZON concentrations.

Ultra-fast RP-HPLC-FD-DAD for quantification of total aflatoxins in maize, rice, wheat, peanut and poultry feed without sample clean up, and population exposure risk assessment in Katsina, Nigeria: an optimization study

This study reports the development and validation of a simple, yet efficient method called the ultra-fast reverse phase high-performance liquid chromatography with fluorescence and photodiode array detector (UF-RP-HPLC-FD-DAD) to extract and quantify the total aflatoxin from grains and poultry feed. The proposed method is used to determine the total aflatoxin content in 150 samples of maize, rice, wheat, peanut and poultry feed obtained from open markets in a state in Nigeria. The extent of consumer exposure to aflatoxins and the risk of developing hepatocellular carcinoma (HCC) are evaluated. The UF-RP-HPLC-FD-DAD method was found to be satisfactorily accurate, sensitive and reliable as ascertained by its excellent validation outcomes (R² > 0.999, LoD < 0.08 ng g^-1, LoQ < 0.2 ng g^-1, recovery = 90-102%). The aflatoxin levels in food grains and poultry feed samples obtained in this study implied a moderate dietary exposure of between 10.67 and 20.77 ng/kg BW/day, in which the risk of developing HCC was estimated to be between 6.27 and 21.40% per 100,000 adults/year. Hence, greater monitoring of marketed food and feed is required, besides the deployment of strict controls and preventive techniques to minimize the population's exposure to a high dietary level of aflatoxins.

Development and validation of quantitative thin layer chromatographic technique for determination of total aflatoxins in poultry feed and food grains without sample clean-up

OBJECTIVE

The purpose of this work is to develop and validate an appropriate solvent solution and quantitative thin layer chromatography (TLC) method for determining the aflatoxins content of chicken feeds and dietary grains.

MATERIALS AND METHODS

To obtain the optimal mobile phase, samples were extracted with methanol/water (3:1) + 5% sodium chloride and partitioned using several solvent systems using preparative TLC. Camag TLC scanner 3 was used to scan the TLC plates at 366 nm and quantify them using JustTLC software. The method was tested for linearity, specificity, accuracy, precision, sensitivity, and robustness in accordance with ICH recommendations, and then utilized to screen 132 Nigerian poultry/food samples for total aflatoxins (TAFs).

RESULTS

The best separation of aflatoxins was achieved using acetonitrile and dichloromethane (3:17) mobile phase over an average run time of 45 min, resulting in linear calibration curves (R2 > 0.99) in the concentration range limit of quantitation (LoQ) to 50 ng/spot with a limit of detection of <2.0 ng/g and a LoQ of <4.0 ng/gm for all aflatoxins in all spiked samples. When the proposed TLC method was compared to an optimized high-performance liquid chromatography method, an excellent linear regression was obtained (R2 > 95%). Seventy seven (58.33%) of the 132 samples examined were positive for aflatoxins, with mean values ranging from 3.57 ± 2.55 to 37.31 ± 34.06 ng/gm for aflatoxin B1 and 6.67 ± 0.00 to 38.02 ± 31.52 ng/gm for TAFs, respectively.

CONCLUSIONS

The results demonstrate the feasibility of using the suggested TLC method in conjunction with a novel solvent solution (free of carcinogenic chloroform) for the rapid and accurate measurement of TAFs in foods/feeds.

Effective Detoxification of Aflatoxin B1 and Ochratoxin A Using Magnetic Graphene Oxide Nanocomposite: Isotherm and Kinetic Study

One of the approaches for reducing exposure to mycotoxins is to lessen their bioavailability by applying nanocomposite adsorbents. Magnetic graphene oxide (MGO) is a new class of nanostructured multifunctional nanocomposite materials, which play a vital role as an adsorbent. The primary aim of this study is to apply response surface methodology (RSM) to optimize the influence of pH within the range of 3 to 7, time (3–7 h), and temperature (30–50 °C), on the simultaneous detoxification of aflatoxin B1 (AFB1) and ochratoxin A (OTA) by using MGO. The optimal condition was obtained at pH 5, 5 h, and 40 °C. Further investigation of the adsorption evaluation was carried out by studying different parameters, such as the influence of contact time, initial mycotoxins concentration, and temperature. According to the experimental data, it can be concluded that the pseudo-second-order kinetic model and the Freundlich isotherm fitted well. The capability of adsorption for the Freundlich model was calculated as 153 and 95 ng/g for AFB1 and OTA, respectively. The thermodynamic study showed that the sorption studies act spontaneously as an exothermic process. These findings suggest that the application of MGO as a nanocomposite is of great significance for the detoxification of mycotoxins.

Development of an Improved Method of Sample Extraction and Quantitation of Multi-Mycotoxin in Feed by LC-MS/MS

A multi-mycotoxin chromatographic method was developed and validated for the simultaneous quantitation of aflatoxins (AFB1, AFB2, AFG1 and AFG2), ochratoxin A (OTA), zearalenone (ZON), deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), fumonisins (FB1, FB2 and FB3), T-2 toxin (T-2) and HT-2 toxin (HT-2) in feed. The three most popular sample preparation techniques for determination of mycotoxins have been evaluated, and the method with highest recoveries was selected and optimized. This modified QuEChERS (quick, easy, cheap, effective, rugged and safe) approach was based on the extraction with acetonitrile, salting-out and cleanup with lipid removal. A reconstitution process in methanol/water was used to improve the MS responses and then the extracts were analyzed by LC-MS/MS. In this method, the recovery range is 70–100% for DON, DAS, FB1, FB2, FB3, HT-2, T-2, OTA, ZON, AFG1, AFG2, AFB1 and AFB2 and 55% for NIV in the spike range of 2–80 µg/kg. Method robustness was determined with acceptable z-scores in proficiency tests and validation experiments.

Mycotoxin Determination in Animal Feed: An LC-FLD Method for Simultaneous Quantification of Aflatoxins, Ochratoxins and Zearelanone in This Matrix

Mycotoxins are toxic compounds for humans and animals that are produced by fungi. Mycotoxin contamination in feed is a global safety concern and effective control of these compounds in this matrix is needed. This study proposes a simple, cost-effective analytical method based on liquid chromatography coupled with a fluorescence detector, which is suitable for the routine monitoring of some of the most important mycotoxins in feed: aflatoxins (G2, G1, B2, and B1), zearalenone, and ochratoxins A and B. Mycotoxin extraction, chromatographic separation and quantification are carried out simultaneously for all mycotoxins. The extraction procedure is performed using acetonitrile, water and orthophosphoric acid (80:19:1). Purification of the extract is carried out using an OASIS PRIME HLB solid-phase extraction cartridge followed by a dispersive liquid–liquid microextraction procedure. Aflatoxins G1 and B1 are derivatized post-column (photochemical reactor at 254 nm) to increase their signal. The method has been validated in feed for pigs, cows, sheep, and poultry with very satisfactory results. The detection limits are 2 μg/kg for aflatoxins B1 and G1, 0.64 μg/kg for aflatoxins B2 and G2, 42 μg/kg for zearalenone, and 5 μg/kg for ochratoxins A and B. These values are low enough to allow for monitoring of these mycotoxins in feed. Global recovery values were between 73.6% and 88.0% for all toxins with a relative standard deviation (RSD) % < 7%. This methodology will facilitate laboratory control and analysis of mycotoxins in feed.

HPLC-DAD-FLD Method for Simultaneous Determination of Mycotoxins in Wheat Bran

Aflatoxins, deoxynivalenol, ochratoxin A and zearalenone are the most important mycotoxins that everyone on its own, in groups or simultaneously contaminate cereals. The external layers of cereal grains (bran) apart from health promoting ingredients are also the most contaminated part with reference to mycotoxin's presence. Therefore, consumption of a high fiber wheat-based diet represent an increased risk to consumer's health. The objective of this study was to develop a simple and reliable high performance liquid chromatography method for the simultaneous determination of these mycotoxins in wheat bran (WB). A double extraction was applied with phosphate buffered saline/methanol and for the clean-up a multi-immunoaffinity column was utilized. The detection was carried out with diode-array and fluorescence detectors linked with a post-column photochemical reactor. After optimization of the chromatographic conditions, all mycotoxins were eluted within ~26 min. Limits of detection for each mycotoxin (0.12-12.58 µg/kg) were below the maximum levels provisioned by European Union regulations. Good linearity was observed for the analytes (r2 ≥ 0.9980). The recovery of analyzed mycotoxins ranged from 70.2 to 105.8%, with a relative standard deviation <12%. The method was successfully applied to quantify mycotoxins in 34 WB samples obtained after pearling of grains that were collected from different regions of Greece.

Solid phase extraction as sample treatment for the determination of Ochratoxin A in foods: A review

Ochratoxin A (OTA) is a mycotoxin produced by two main types of fungi, Aspergillus and Penicillium species. OTA is a natural contaminant found in a large number of different matrices and is considered as a possible carcinogen for humans. Hence, low maximum permitted levels in foods have been established by competent authorities around the world, making essential the use of very sensitive analytical methods for OTA detection. Sample treatment is a crucial step of analytical methodology to get clean and concentrated extracts, and therefore low limits of quantification. Solid phase extraction (SPE) is a useful technique for rapid and selective sample preparation. This sample treatment enables the concentration and purification of analytes from the sample solution or extract by sorption on a solid sorbent. This review is focused on sample treatment procedures based on SPE prior to the determination of OTA in food matrices, published from 2010.

Advanced LC-MS-based methods to study the co-occurrence and metabolization of multiple mycotoxins in cereals and cereal-based food

Liquid chromatography (LC) coupled with mass spectrometry (MS) is widely used for the determination of mycotoxins in cereals and cereal-based products. In addition to the regulated mycotoxins, for which official control is required, LC-MS is often used for the screening of a large range of mycotoxins and/or for the identification and characterization of novel metabolites. This review provides insight into the LC-MS methods used for the determination of co-occurring mycotoxins with special emphasis on multiple-analyte applications. The first part of the review is focused on targeted LC-MS approaches using cleanup methods such as solid-phase extraction and immunoaffinity chromatography, as well as on methods based on minimum cleanup (quick, easy, cheap, effective, rugged, and safe; QuEChERS) and dilute and shoot. The second part of the review deals with the untargeted determination of mycotoxins by LC coupled with high-resolution MS, which includes also metabolomics techniques to study the fate of mycotoxins in plants.

Development of Multiple Heart-Cutting Two-Dimensional Liquid Chromatography Coupled to Quadrupole-Orbitrap High Resolution Mass Spectrometry for Simultaneous Determination of Aflatoxin B1, B2, G1, G2, and Ochratoxin A in Snus, a Smokeless Tobacco Product

The combination of multiple heart-cutting two-dimensional liquid chromatography (MHC-LC/LC) and quadrupole-orbitrap high-resolution mass spectrometry (HRMS) for simultaneous determination of the aflatoxins and ochratoxin A in snus is presented in this work. A C18 capillary column was used as the first dimension (1D) to isolate the aflatoxins and ochratoxin A from the complex matrices; then, a 2-position/10-port high-pressure valve equipped with two 60 μL loops was employed to transfer the heart-cuts of 1D-LC into a pentafluorophenyl (PFP) column for the second dimension (2D) separation. With the better separation of the MHC-LC/LC system, the sensitivity of the method was improved, which is essential for the trace mycotoxins analysis. Furthermore, HRMS performed in parallel reaction monitoring mode was employed to eliminate the interferences, and the sample pretreatment procedure was simplified. A new approach utilizing ethyl acetate with 1% formic acid/water solution was adopted to extract aflatoxins and ochratoxin A in snus, which provided parallel recoveries for aflatoxins and ochratoxin A with higher responses in comparison with the QuEChERS method. A dynamic range between 0.2 and 20 μg/kg was achieved with LOQs of 0.05 μg/kg for aflatoxin B₁, 0.1 μg/kg for aflatoxin B₂, G₁, G₂, and 1.0 μg/kg for ochratoxin A in dry mass of product. The results revealed that the established method exhibited good repeatability and recovery and could be used as a rapid and reliable approach for routine analysis of aflatoxins and ochratoxin A in snus.

Recent Advances in Mycotoxin Determination for Food Monitoring via Microchip

Mycotoxins are one of the main factors impacting food safety. Mycotoxin contamination has threatened the health of humans and animals. Conventional methods for the detection of mycotoxins are gas chromatography (GC) or liquid chromatography (LC) coupled with mass spectrometry (MS), or enzyme-linked immunosorbent assay (ELISA). However, all these methods are time-consuming, require large-scale instruments and skilled technicians, and consume large amounts of hazardous regents and solvents. Interestingly, a microchip requires less sample consumption and short analysis time, and can realize the integration, miniaturization, and high-throughput detection of the samples. Hence, the application of a microchip for the detection of mycotoxins can make up for the deficiency of the conventional detection methods. This review focuses on the application of a microchip to detect mycotoxins in foods. The toxicities of mycotoxins and the materials of the microchip are firstly summarized in turn. Then the application of a microchip that integrates various kinds of detection methods (optical, electrochemical, photo-electrochemical, and label-free detection) to detect mycotoxins is reviewed in detail. Finally, challenges and future research directions in the development of a microchip to detect mycotoxins are previewed.

Rapid Detection and Identification of Mycotoxigenic Fungi and Mycotoxins in Stored Wheat Grain

This study aimed to assess the occurrence of toxigenic fungi and mycotoxin contamination in stored wheat grains by using advanced molecular and analytical techniques. A multiplex polymerase chain reaction (PCR) strategy was established for rapid identification of mycotoxigenic fungi, and an improved analytical method was developed for simultaneous multi-mycotoxin determination in wheat grains by liquid chromatography-tandem mass spectrometry (LC/MS/MS) without the need for any clean-up. The optimized multiplex PCR method was highly specific in detecting fungal species containing species-specific and mycotoxin metabolic pathway genes. The method was applied for evaluation of 34 wheat grain samples collected from storage warehouses for the presence of mycotoxin-producing fungi, and a few samples were found positive for Fusarium and Aspergillus species. Further chemical analysis revealed that 17 samples contained mycotoxins above the level of detection, but only six samples were found to be contaminated over the EU regulatory limits with at least one mycotoxin. Aflatoxin B₁, fumonisins, and deoxynivalenol were the most common toxins found in these samples. The results showed a strong correlation between the presence of mycotoxin biosynthesis genes as analyzed by multiplex PCR and mycotoxin detection by LC/MS/MS. The present findings indicate that a combined approach might provide rapid, accurate, and sensitive detection of mycotoxigenic species and mycotoxins in wheat grains.

Risks to human and animal health related to the presence of deoxynivalenol and its acetylated and modified forms in food and feed

Deoxynivalenol (DON) is a mycotoxin primarily produced by Fusarium fungi, occurring predominantly in cereal grains. Following the request of the European Commission, the CONTAM Panel assessed the risk to animal and human health related to DON, 3-acetyl-DON (3-Ac-DON), 15-acetyl-DON (15-Ac-DON) and DON-3-glucoside in food and feed. A total of 27,537, 13,892, 7,270 and 2,266 analytical data for DON, 3-Ac-DON, 15-Ac-DON and DON-3-glucoside, respectively, in food, feed and unprocessed grains collected from 2007 to 2014 were used. For human exposure, grains and grain-based products were main sources, whereas in farm and companion animals, cereal grains, cereal by-products and forage maize contributed most. DON is rapidly absorbed, distributed, and excreted. Since 3-Ac-DON and 15-Ac-DON are largely deacetylated and DON-3-glucoside cleaved in the intestines the same toxic effects as DON can be expected. The TDI of 1 μg/kg bw per day, that was established for DON based on reduced body weight gain in mice, was therefore used as a group-TDI for the sum of DON, 3-Ac-DON, 15-Ac-DON and DON-3-glucoside. In order to assess acute human health risk, epidemiological data from mycotoxicoses were assessed and a group-ARfD of 8 μg/kg bw per eating occasion was calculated. Estimates of acute dietary exposures were below this dose and did not raise a health concern in humans. The estimated mean chronic dietary exposure was above the group-TDI in infants, toddlers and other children, and at high exposure also in adolescents and adults, indicating a potential health concern. Based on estimated mean dietary concentrations in ruminants, poultry, rabbits, dogs and cats, most farmed fish species and horses, adverse effects are not expected. At the high dietary concentrations, there is a potential risk for chronic adverse effects in pigs and fish and for acute adverse effects in cats and farmed mink.

Aflatoxins in cereals: worldwide occurrence and dietary risk assessment

The worldwide occurrence of aflatoxins (AFB1, AFB2, AFG1, AFG2), genotoxic mycotoxins, in raw maize, rice, sorghum and wheat samples collected since the year 2000 was evaluated using published data and occurrence data from the GEMS/Food database (https://extranet.who.int/gemsfood). Dietary risk assessments were conducted using GEMS/Food total aflatoxin occurrence and food consumption data obtained from the 17 Cluster Diets. Risk characterisation arising from aflatoxin exposure was conducted using both cancer risk and margin of exposure (MOE) approaches. A total of 89 publications were retrieved from the literature, reporting data related to 18,097 samples, of which 37.6% were positive for at least one aflatoxin. The total upper bound (UB) mean for all samples analysed was 13.6 μg/kg, and was higher for rice (24.6 μg/kg) and sorghum (25.9 μg/kg). Of data related to the analysis of 4,536 samples reported to GEMS/Food database, 12.7% were positive for at least one aflatoxin. The total UB mean was 1.9 μg/kg, and was higher for rice (2.4 μg/kg) and maize (1.6 μg/kg). Total intakes ranged from 3.0 ng/kg bw/day (Cluster C11) to 17.1 ng/kg bw/day (Cluster C09). On average, the consumption of rice contributed to 41.6% of the total aflatoxin intake in all clusters, followed by wheat (35.4%), maize (21.2%) and sorghum (1.8%). The lowest cancer risk was found in cluster C11 (0.057 cancers/year/105 individuals), and the highest in cluster C09 (0.467 cancers/year/105 individuals). MOE ranged from 56 (C11) to 10 (C09), indicating a potential risk to consumers. These results highlight the need for continuous action by health authorities to decrease aflatoxin contamination in cereals, as they are staple foods in diets worldwide. These actions include the enforcement of code of practices at the national level and the establishment of maximum contamination levels by the Codex System.

The relationship between ergosterol and mycotoxin contamination in maize from various countries

Maize is a good substrate for fungal growth and production of toxic secondary metabolites or mycotoxins. The relationships between the fungal biomarker ergosterol (ERG) and mycotoxins such as aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEA) were investigated in maize collected from four different geographic locations. ERG and mycotoxins were measured by high-performance liquid chromatography with UV and fluorescence detection. ERG did not correlate with AFs in 139 analysed samples. OTA contamination was found in only one sample from the North American region. A significant correlation (r (2) = 0.82) was observed between ERG and ZEA. AFs and ZEA were found in 47% of all samples. Half of the samples contained more than two mycotoxins. Levels of ERG and mycotoxin contamination differed by geographical region. North American and Asian samples had higher frequencies and levels of ERG and mycotoxin contamination. No AF contamination was observed in European samples (limit of detection 0.025 μg/kg for AFB1). We conclude that samples containing less than 3 mg/kg ERG in most cases do not exceed the EU maximum limits for AFs, OTA and ZEA.

Dietary glutamate supplementation ameliorates mycotoxin-induced abnormalities in the intestinal structure and expression of amino acid transporters in young pigs

The purpose of this study was to investigate the hypothesis that dietary supplementation with glutamic acid has beneficial effects on growth performance, antioxidant system, intestinal morphology, serum amino acid profile and the gene expression of intestinal amino acid transporters in growing swine fed mold-contaminated feed. Fifteen pigs (Landrace×Large White) with a mean body weight (BW) of 55 kg were randomly divided into control group (basal feed), mycotoxin group (contaminated feed) and glutamate group (2% glutamate+contaminated feed). Compared with control group, mold-contaminated feed decreased average daily gain (ADG) and increased feed conversion rate (FCR). Meanwhile, fed mold-contaminated feed impaired anti-oxidative system and intestinal morphology, as well as modified the serum amino acid profile in growing pigs. However, supplementation with glutamate exhibited potential positive effects on growth performance of pigs fed mold-contaminated feed, ameliorated the imbalance antioxidant system and abnormalities of intestinal structure caused by mycotoxins. In addition, dietary glutamate supplementation to some extent restored changed serum amino acid profile caused by mold-contaminated feed. In conclusion, glutamic acid may be act as a nutritional regulating factor to ameliorate the adverse effects induced by mycotoxins.

Validation of a UHPLC-MS/MS method for quantification of zearalenone, α-zearalenol, β-zearalenol, α-zearalanol, β-zearalanol and zearalanone in human urine

Humans can be exposed to mycotoxins through the diet. Evaluation of exposure levels to mycotoxins can be performed by direct determination in urine. The present work proposes a sensitive ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for the determination of zearalenone (ZON) and its five metabolites (α-zearalenol [α-ZOL], β-zearalenol [β-ZOL], α-zearalanol [zeranol, α-ZAL], β-zearalanol [teranol, β-ZAL] and zearalanone [ZAN]) in human urine samples. The method involves the enzymatic hydrolysis of the samples, extraction of the analytes using liquid-liquid extraction (LLE) with ethyl acetate/formic acid (99:1 v/v) and a cleanup step using hexane, prior to their quantification by UHPLC-MS/MS, using an electrospray ionization (ESI) interface in the negative mode. Zearalenone-d6 (ZON-d6) was used as surrogate. The limits of detection and the limits of quantification ranged from 0.03 to 0.3ngmL(-1) and from 0.1 to 1.0ngmL(-1), respectively. The method was validated using matrix-matched calibration and a spike recovery assay. Recovery rates for spiked samples ranged from 96% to 104%, with relative standard deviations lower than 8.5%. This method was satisfactorily applied to 42 urine samples from Tunisian women for the determination of zearalenone and its five metabolites.

Multi-mycotoxin analysis of finished grain and nut products using high-performance liquid chromatography-triple-quadrupole mass spectrometry

Mycotoxins in foods have long been recognized as potential health hazards due to their toxic and carcinogenic properties. A simple and rapid method was developed to detect 26 mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, and ergot alkaloids) in corn, rice, wheat, almond, peanut, and pistachio products using high-performance liquid chromatography-triple-quadrupole mass spectrometry. Test portions of homogenized grain or nut products were extracted with acetonitrile/water (85:15, v/v), followed by high-speed centrifugation and dilution with water. Mean recoveries (± standard deviations) were 84 ± 6, 89 ± 6, 97 ± 9, 87 ± 12, 104 ± 16, and 92 ± 18% from corn, rice, wheat, almond, peanut, and pistachio products, respectively, and the matrix-dependent instrument quantitation limits ranged from 0.2 to 12.8 μg/kg, depending on the mycotoxin. Matrix effects, as measured by the slope ratios of matrix-matched and solvent-only calibration curves, revealed primarily suppression and were more pronounced in nuts than in grains. The measured mycotoxin concentrations in 11 corn and wheat reference materials were not different from the certified concentrations. Nineteen mycotoxins were identified and measured in 35 of 70 commercial grain and nut products, ranging from 0.3 ± 0.1 μg/kg (aflatoxin B1 in peanuts) to 1143 ± 87 μg/kg (fumonisin B1 in corn flour). This rapid and efficient method was shown to be rugged and effective for the multiresidue analysis of mycotoxins in finished grain and nut products.

Multiclass mycotoxin analysis in Silybum marianum by ultra high performance liquid chromatography-tandem mass spectrometry using a procedure based on QuEChERS and dispersive liquid-liquid microextraction

Ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) has been proposed for the determination of 15 mycotoxins in milk thistle (Silybum marianum), including aflatoxins, fumonisins, trichothecenes, ochratoxin A, citrinin, sterigmatocystin and zearalenone. The mycotoxins were detected by electrospray ionization in positive ion mode and multiple reaction monitoring (MRM), achieving the separation in about 4min. Sample treatment consisted of a modified method based on a first step using a QuEChERS-based procedure which allowed the determination of fumonisin B1, fumonisin B2, nivalenol, deoxynivalenol and fusarenon-X, and a subsequent clean-up based on dispersive liquid-liquid microextraction (DLLME) for the determination of the rest of mycotoxins. The method has been validated in extract and seeds of milk thistle, obtaining limits of quantification lower than those usually permitted by legislation in food matrices, with precisions lower than 10%. Recoveries were between 62.3% and 98.9%, except for zearalenone in seeds samples and citrinin in extract. The method was also applied for studying the occurrence of these mycotoxins in market samples (six samples of seeds, three of them purchased in bulk in a street vendor, and one natural extract of milk thistle), and HT-2, T-2 and zearalenone have been found in some of the samples. To the best of our knowledge, this is the first time that this type of treatment has been used for these complex food matrices, allowing the analyses of the most important mycotoxins.

Developments in mycotoxin analysis: an update for 2010-2011

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2010 and mid-2011. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Analytical methods for mycotoxins continue to be developed and published. Despite much interest in immunochemical methods and in the rapid development of LC-MS methodology, more conventional methods, sometimes linked to novel clean-up protocols, have also been the subject of research publications over the above period. Occurrence of mycotoxins falls outside the main focus of this review; however, where relevant to analytical method development, this has been mentioned.

Quantitative analysis of mycotoxins in cereal foods by collision cell fragmentation-high-resolution mass spectrometry: performance and comparison with triple-stage quadrupole detection

A liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method for the simultaneous determination of aflatoxins (B(1), B(2), G(1), G(2)), ochratoxin A, deoxynivalenol, zearalenone, T-2 and HT-2 toxins in wheat flour, barley flour and crisp bread was developed. Mycotoxin fragmentation patterns obtained by high-energy collision dissociation (HCD) were investigated to obtain quantitative and confirmatory information (two characteristic masses per mycotoxin) using Orbitrap™-based high-resolution mass spectrometry. LC-HRMS (full-scan) detection carried out by HCD allows the monitoring of the pseudo-molecular ion and an additional characteristic fragment (for each mycotoxin) with mass accuracy in the range 0.1-3.9 ppm, meeting current European regulatory requirements for LC-MS confirmatory analysis. A sample preparation procedure based on polymeric solid-phase extraction cartridges was applied, allowing recoveries higher than 74% for nine mycotoxins, with a relative standard deviation lower than 13%. Detection limits in the range 0.5-3.4 µg kg(-1) were obtained for three cereal matrices. A critical comparison between the proposed method and a validated method based on triple quadrupole mass spectrometry showed similar performance in terms of detection limits, recoveries and repeatability, and matrix effects. Based on an efficient sample extraction and clean-up, the LC-HCD-HRMS method reported here represents a reliable and robust alternative tool for mycotoxin analysis in food matrices as compared with well-established triple quadrupole-based approaches.