Direct analysis of several Fusarium mycotoxins in cereals by capillary gas chromatography-mass spectrometry

Development of an immunoaffinity chromatography and LC-MS/MS method for the determination of 6 zearalenones in animal feed

A novel and simple method for detecting 6 zearalenones in animal feed using liquid chromatography coupled with triple quadrupole mass spectrometry (LC-MS/MS) and immunoaffinity columns (IAC) was developed. The chromatographic peaks of the 6 zearalenones were successfully identified by comparing their retention times and mass spectrum with reference standards. The mobile phase was composed of mobile phase A (water) and B (0.5% formic acid in ACN). Method validation was performed with linearity, sensitivity, selectivity, accuracy and precision. The limits of detection (LODs) for the instrument used to study zearalenones ranged from 0.3 to 1.1 μg/kg, and the limits of quantification (LOQs) ranged from 1.0 to 2.2 μg/kg. Average recoveries of the 6 zearalenones ranged from 82.5% to 106.4%. Method replication resulted in intra-day and inter-day peak area variation of <3.8%. The developed method was specific and reliable and is suited for the routine analysis of zearalenones in animal feed.

Natural occurrence, analysis, and prevention of mycotoxins in fruits and their processed products

Mycotoxins are small toxic chemical products formed as the secondary metabolites by fungi that readily contaminate foods with toxins in the field or after harvest. The presence of mycotoxins, such as aflatoxins, ochratoxin A, and patulin, in fruits and their processed products is of high concern for human health due to their properties to induce severe acute and chronic toxicity at low-dose levels. Currently, a broad range of detection techniques used for practical analysis and detection of a wide spectrum of mycotoxins are available. Many analytical methods have been developed for the determination of each group of these mycotoxins in different food matrices, but new methods are still required to achieve higher sensitivity and address other challenges that are posed by these mycotoxins. Effective technologies are needed to reduce or even eliminate the presence of the mycotoxins in fruits and their processed products. Preventive measures aimed at the inhibition of mycotoxin formation in fruits and their processed products are the most effective approach. Detoxification of mycotoxins by different physical, chemical, and biological methods are less effective and sometimes restricted because of concerns of safety, possible losses in nutritional quality of the treated commodities and cost implications. This article reviewed the available information on the major mycotoxins found in foods and feeds, with an emphasis of fruits and their processed products, and the analytical methods used for their determination. Based on the current knowledge, the major strategies to prevent or even eliminate the presence of the mycotoxins in fruits and their processed products were proposed.

Multiclass mycotoxin analysis in food, environmental and biological matrices with chromatography/mass spectrometry

Mold metabolites that can elicit deleterious effects on other organisms are classified as mycotoxins. Human exposure to mycotoxins occurs mostly through the intake of contaminated agricultural products or residues due to carry over or metabolite products in foods of animal origin such as milk and eggs, but can also occur by dermal contact and inhalation. Mycotoxins contained in moldy foods, but also in damp interiors, can cause diseases in humans and animals. Nephropathy, various types of cancer, alimentary toxic aleukia, hepatic diseases, various hemorrhagic syndromes, and immune and neurological disorders are the most common diseases that can be related to mycotoxicosis. The absence or presence of mold infestation and its propagation are seldom correlated with mycotoxin presence. Mycotoxins must be determined directly, and suitable analytical methods are necessary. Hundreds of mycotoxins have been recognized, but only for a few of them, and in a restricted number of utilities, a maximum acceptable level has been regulated by law. However, mycotoxins seldom develop alone; more often various types and/or classes form in the same substrate. The co-occurrence might render the individual mycotoxin tolerance dose irrelevant, and therefore the mere presence of multiple mycotoxins should be considered a risk factor. The advantage of chromatography/mass spectrometry (MS) is that many compounds can be determined and confirmed in one analysis. This review illustrates the state-of-the-art of mycotoxin MS-based analytical methods for multiclass, multianalyte determination in all the matrices in which they appear. A chapter is devoted to the history of the long-standing coexistence and interaction among humans, domestic animals and mycotoxicosis, and the history of the discovery of mycotoxins. Quality assurance, although this topic relates to analytical chemistry in general, has been also examined for mycotoxin analysis as a preliminary to the systematic literature excursus. Sample handling is a crucial step to devise a multiclass analytical method; so when possible, it has been treated separately for a better comparison before tackling the instrumental part of the whole analytical method. This structure has resulted sometimes in unavoidable redundancies, because it was also important to underline the interconnection. Most reviews do not deal with all the possible mycotoxin sources, including the environmental ones. The focus of this review is the analytical methods based on MS for multimycotoxin class determination. Because the final purpose to devise multimycotoxin analysis should be the assessment of the danger to health of exposition to multitoxicants of natural origin (and possibly also the interaction with anthropogenic contaminants), therefore also the analytical methods for environmental relevant mycotoxins have been thoroughly reviewed. Finally, because the best way to shed light on actual risk assessment could be the individuation of exposure biomarkers, the review covers also the scarce literature on biological fluids.

An overview of conventional and emerging analytical methods for the determination of mycotoxins

Mycotoxins are a group of compounds produced by various fungi and excreted into the matrices on which they grow, often food intended for human consumption or animal feed. The high toxicity and carcinogenicity of these compounds and their ability to cause various pathological conditions has led to widespread screening of foods and feeds potentially polluted with them. Maximum permissible levels in different matrices have also been established for some toxins. As these are quite low, analytical methods for determination of mycotoxins have to be both sensitive and specific. In addition, an appropriate sample preparation and pre-concentration method is needed to isolate analytes from rather complicated samples. In this article, an overview of methods for analysis and sample preparation published in the last ten years is given for the most often encountered mycotoxins in different samples, mainly in food. Special emphasis is on liquid chromatography with fluorescence and mass spectrometric detection, while in the field of sample preparation various solid-phase extraction approaches are discussed. However, an overview of other analytical and sample preparation methods less often used is also given. Finally, different matrices where mycotoxins have to be determined are discussed with the emphasis on their specific characteristics important for the analysis (human food and beverages, animal feed, biological samples, environmental samples). Various issues important for accurate qualitative and quantitative analyses are critically discussed: sampling and choice of representative sample, sample preparation and possible bias associated with it, specificity of the analytical method and critical evaluation of results.

Analytical methods for determination of mycotoxins: a review

Mycotoxins are small (MW approximately 700), toxic chemical products formed as secondary metabolites by a few fungal species that readily colonise crops and contaminate them with toxins in the field or after harvest. Ochratoxins and Aflatoxins are mycotoxins of major significance and hence there has been significant research on broad range of analytical and detection techniques that could be useful and practical. Due to the variety of structures of these toxins, it is impossible to use one standard technique for analysis and/or detection. Practical requirements for high-sensitivity analysis and the need for a specialist laboratory setting create challenges for routine analysis. Several existing analytical techniques, which offer flexible and broad-based methods of analysis and in some cases detection, have been discussed in this manuscript. There are a number of methods used, of which many are lab-based, but to our knowledge there seems to be no single technique that stands out above the rest, although analytical liquid chromatography, commonly linked with mass spectroscopy is likely to be popular. This review manuscript discusses (a) sample pre-treatment methods such as liquid-liquid extraction (LLE), supercritical fluid extraction (SFE), solid phase extraction (SPE), (b) separation methods such as (TLC), high performance liquid chromatography (HPLC), gas chromatography (GC), and capillary electrophoresis (CE) and (c) others such as ELISA. Further currents trends, advantages and disadvantages and future prospects of these methods have been discussed.

Zearalenone and its metabolites: occurrence, detection, toxicity and guidelines

Zearalenone is a mycotoxin produced by some Fusarium species in food and feed. From a global perspective, Fusarium mycotoxins may be considered as metabolites of particular importance to animal health and productivity. The aim of this review is to collect and summarise information concerning the properties of zearalenone, its derivatives and their biotransformation. Data on the occurrence and toxicity of zearalenone and a comparison of analytical methods used in zearalenone identification and quantification will also be discussed. As our awareness and understanding of the risks associated with zearalenone exposure increase, some countries set official or recommended limits in certain commodities.

Multiresidue determination of thermolabile insecticides in cereal products by gas chromatography-mass spectrometry: Evaluation with on-column injection and conventional hot splitless injection

This communication presents a study on the simultaneous determination of thermolabile N-methylcarbamate and organophosphorus insecticides in cereal products by gas chromatography-mass spectrometry. The thermal stability of the multiple insecticides was evaluated with conventional hot splitless injection and on-column injection. The results obtained by GC-MS with these two injection techniques were compared in terms of the recovery, the limit of detection, the limit of qualification, and the reproducibility. With on-column injection, the pesticide recoveries in cereal samples were better than 82%, with relative standard deviations lower than 5.4%. The limits of qualification for most insecticides were in the range of 0.009-0.08 mg/kg, i. e. lower than the maximum residue limits established for insecticides in cereal products by the European Union. The long-term stability using on-column injection for analysis of insecticides in real samples was evaluated and normal chromatographic performance could be obtained within 50 analyses. The results revealed that it was possible for application of on-column injection in the analysis of thermolabile multiple insecticides in food sample after comprehensive sample clean-up, despite the highly contaminated nature of the column system.

Chromatographic methods for the simultaneous determination of mycotoxins and their conjugates in cereals

About 300-400 mycotoxins are known today. To some extent these compounds show very different physicochemical properties, which led to a vast quantity of analytical methods for single toxins or certain classes of mycotoxins in a variety of matrices. Due to synergistic effects of co-occurring toxins, endeavors have been made to simultaneously detect and quantify several classes of mycotoxins. This paper discusses several of the published LC-MS/MS multi-mycotoxin-methods and also introduces a new method, which allows the concurrent detection and quantification of 90 major mycotoxins and other secondary fungal metabolites in cereals. Even more, known plant derived metabolites of mycotoxins, like zearalenone-4-glucoside or deoxynivalenol-3-glucoside are included in this method. The significance of mycotoxin conjugates is briefly discussed as well.

Fusarium toxins of the scirpentriol subgroup: a review

Scirpentriol and its seven acetylated derivatives comprise a family of type-A trichothecene toxins produced by several species of Fusarium fungi. Out of this group 4,15-diacetoxyscirpenol has attracted most attention. It elicits toxic responses in several species and was detected in a variety of substrates. Out of the three possible monoacetylated derivatives 15-monoacetoxyscirpenol and the parent alcohol scirpentriol received some attention, whereas the remaining members of the family were mentioned in few reports. The present review deals with the structure, biosynthesis, analysis and toxicity of scirpentriol toxins. Formation by Fusarium species as well as culture conditions used for toxigenicity studies are reviewed; data about the natural occurrence of scirpentriol toxins in different cereal types, cereal associated products as well as in non-grain matrices including potato and soya bean are reported. Basing on literature reports about the toxicity of scirpentriol toxins an attempt is made to summarise the state of knowledge for risk evaluation for human and animal health.

Selective Sample Cleanup by Reusable Sol−Gel Immunoaffinity Columns for Determination of Deoxynivalenol in Food and Feed Samples

The paper describes the development of a simple and highly selective method for the determination of deoxynivalenol (DON) in food and feed samples. It combines sample cleanup with sol-gel immunoaffinity columns containing monoclonal anti-DON antibodies and quantification of DON by high-performance liquid chromatography with ultraviolet detection. The sol-gel immunoaffinity columns are as selective as commercial DON immunoaffinity columns but superior with regard to production costs, storage stability, and reusability. In applying the method for the analysis of maize, wheat, and spaghetti samples, it offers detection limits (LOD, S/N = 3) of 240, 200, and 207 ng/g, and recoveries of 83, 99, and 97%, respectively.

Characterization and application of isotope-substituted (13C15)-deoxynivalenol (DON) as an internal standard for the determination of DON

The powerful combination of liquid chromatography and mass spectrometry (MS) is often limited by matrix effects during ionization in the MS ion source. The use of fully isotope-substituted (13C15)-deoxynivalenol ((13C15)-DON) as an internal standard (IS) corrects matrix effects and improves the accuracy of analytical methods using mass spectrometry for the quantitative determination of the Fusarium mycotoxin deoxynivalenol (DON). The IS was characterized with respect to its chromatographic purity by liquid chromatography-ultraviolet light and its isotope distribution by time-of-flight mass spectrometry. Its low-energy collision-induced dissociation behaviour was compared with DON. Moreover, this work describes the successful application of (13C15)-DON as IS for the determination of DON in maize using high-performance liquid chromatography (HPLC) electrospray (ESI) with tandem mass spectrometry. The results demonstrate that the IS can successfully correct for fluctuations during extraction and clean-up of the sample as well as the ionization of DON in the MS ion source. Random variations in ionization affect the IS in the same way as the analyte. Recoveries for DON in maize of 76% +/- 1.9% (external calibration) or 101% +/- 2.4% (internal calibration) were reached, respectively, after sample clean-up.

Trends in detection of warfare agents. Detection methods for ricin, staphylococcal enterotoxin B and T-2 toxin

An overview of the different detection methods available for ricin, staphylococcal enterotoxin B (SEB) and T-2 toxin is presented here. These toxins are potential biological warfare agents (BWA). The aim of this review is not to cover all the papers that had been published but rather to give an overall picture of the trend in the detection methodologies for potential biological warfare agents as we do see the emerging threats from these three toxins. The advantages and disadvantages of each methodology as well as the detection limit will be reviewed. It seems that mass spectrometry has created a niche for analysis of proteinaceous toxins, ricin and SEB as well as molecular toxin, T-2 toxin given its high sensitivity, high selectivity, high specificity and capability to identify and quantify unknown agents simultaneously in a short time frame. But its main drawbacks are its sophisticated instrumentation and its high cost. Improvised immunoassay may be an alternative.

New possibilities of matrix-assisted laser desorption ionization time of flight mass spectrometry to analyze barley malt quality. Highly sensitive detection of mycotoxins

The occurrence of mycotoxins in agricultural commodities is a major health concern for livestock, humans, and the environment. Barley and subsequently malt quality is of fundamental importance to obtain good quality beer. Classical methods of analysis often require tedious, laborious, and expensive processes. Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) instrumentation enables highly sensitive and fast analysis and/or detection using a very small sample. The possibilities of MALDI-TOF MS for he identification and/or detection of trichothecene mycotoxins (deoxynivalenol (DON) and nivalenol (NIV), respectively) in barley malt were examined, and it was found that almost all classical MALDI matrices failed to ionize the compounds being studied. This detailed study of the ionization conditions and the search for unconventional matrices led to the discovery of suitable MALDI matrices, which enable ionization of trichothecene mycotoxins. These were: fine powdered synthetic diamond, sodium azide, or hydrazine hydrate. It is possible to detect 8.5 x 10(-12) mol (2.5 ng) of deoxynivalenol or 64 x 10(-12) mol (20 ng) of nivalenol in just 1 microL of barley malt extract (equivalent to 600 microg of DON in 1 kg of barley malt). The procedure developed enables fast determination of DON and NIV in barley, malt, or similar products.

A new solid phase extraction clean-up method for the determination of 12 type A and B trichothecenes in cereals and cereal-based food by LC-MS/MS

A new reliable and cost-efficient solid phase extraction-based clean-up method for the determination of 12 type A and B trichothecenes [deoxynivalenol (DON), nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, fusarenon-X, T-2 toxin, HT-2 toxin, neosolaniol, monoacetoxy-scirpenol, diacetoxyscirpenol, T-2 triol and T-2 tetraol] in cereals and cereal-based food is presented. Furthermore, the suitability for the simultaneous determination of zearalenone is examined. Toxins were extracted from cereal samples using ACN/water (80/20, v/v), purified by means of a new Bond Elut Mycotoxin column and analyzed via liquid chromatography-electrospray ionization tandem mass spectrometry. Limits of detection were calculated for the matrix wheat and ranged from 0.3 to 5 ng/g, depending on the toxin. Average recovery rates for the tested compounds in seven cereal-based matrices have been determined ranging from 65 to 104%. The relative standard deviations of the complete method ranged from 2.67 (DON, wheat) to 20.0% (T-2 toxin, oats).

Recent advances in mycotoxin determination in food and feed by hyphenated chromatographic techniques/mass spectrometry

Mycotoxins are fungal toxins produced by molds, which occur universally in food and feed derivatives, and are produced under certain environmental conditions in the field before harvest, post-harvest, during storage, processing, and feeding. Mycotoxin contamination is one of the most relevant and worrisome problem concerning food and feed safety because it can cause a variety of toxic acute and chronic effects in human and animals. In this review we report the use of mass spectrometry in connection with chromatographic techniques for mycotoxin determination by considering separately the most diffuse class of mycotoxins: patulin, aflatoxins, ochratoxin A, zearalenone, trichothecenes, and fumonisins. Although the selectivity of mass spectrometry is unchallenged if compared to common GC and LC detection methods, accuracy, precision, and sensitivity may be extremely variable concerning the different mycotoxins, matrices, and instruments. The sensitivity issue may be a real problem in the case of LC/MS, where the response can be very different for the different ionization techniques (ESI, APCI, APPI). Therefore, when other detection methods (such as fluorescence or UV absorbance) can be used for the quantitative determination, LC/MS appears to be only an outstanding confirmatory technique. In contrast, when the toxins are not volatile and do not bear suitable chromophores or fluorophores, LC/MS appears to be the unique method to perform quantitative and qualitative analyses without requiring any derivatization procedure. The problem of exact quantitative determination in GC/MS and LC/MS methods is particularly important for mycotoxin determination in food, given the high variability of the matrices, and can be solved only by the use of isotopically labeled internal standards or by the use of ionization interfaces able to lower matrix effects and ion suppressions. When the problems linked to inconstant ionization and matrix effects will be solved, only MS detectors will allow to simplify more and more the sample preparation procedures and to avoid clean-up procedures, making feasible low-cost, high-throughput determination of mycotoxins in many different food matrices.

Determination of 12 type A and B trichothecenes in cereals by liquid chromatography-electrospray ionization tandem mass spectrometry

A new sensitive method for the simultaneous determination of 12 trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, fusarenon X, T-2 toxin, HT-2 toxin, neosolaniol, monoacetoxyscirpenol, diacetoxyscirpenol, T-2 triol, and T-2 tetraol) by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) is presented. The development of the method and investigations on the matrix influence on the MS signal are described in particular. The matrix effect was thereby minimized by using an internal standard, a special mobile phase, and specific fragmentation parameters. The sample was extracted with acetonitrile/water (84:16, v/v), and the extract was cleaned up with a MycoSep 227 column. Quantification was based on the internal standard de-epoxy-deoxynivalenol. Calibration curves were linear between 16 and 1600 ng/g, and the limits of detection ranged from 0.18 to 5.0 ng/g. The developed method was applied for the determination of trichothecenes in 120 naturally contaminated wheat and oat samples.

Survival of the biocontrol agents Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116 on the spikes of barley in the field

Fusarium head blight (FHB) caused by Fusarium graminearum is a devastating disease that results in extensive yield losses to wheat and barley. A green fluorescent protein (GFP) expressing plasmid pRP22-GFP was constructed for monitoring the colonization of two biocontrol agents, Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116, on the spikes of barley and their effect on suppression of FHB. Survival and colonization of the Brevibacillus brevis ZJY-1 and Bacillus subtilis ZJY-116 strains on spikes of barley were observed by tracking the bacterial transformants with GFP expression. Our field study revealed that plasmid pRP22-GFP was stably maintained in the bacterial strains without selective pressure. The retrieved GFP-tagged strains showed that the bacterial population fluctuation accorded with that of the rain events. Furthermore, both biocontrol strains gave significant protection against FHB on spikes of barley in fields. The greater suppression of barley FHB disease was resulted from the treatment of barley spikes with biocontrol agents before inoculation with F. graminearum.

Rapid simultaneous determination of major type A- and B-trichothecenes as well as zearalenone in maize by high performance liquid chromatography-tandem mass spectrometry

A novel method for the simultaneous determination of the Fusarium mycotoxins nivalenol, deoxynivalenol, fusarenon-X, 3-acetyl-deoxynivalenol, the sum of 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol, diacetoxy-scirpenol, HT-2 toxin, T-2 toxin and zearalenone in maize has been developed using gradient RP-LC with atmospheric pressure chemical ionization triple quadrupole mass spectrometry (LC-APCI-MS/MS). Swift clean-up of maize samples was performed with MycoSep #226 columns. Quantification of zearalenone was performed with zearalanone as internal standard (IS), while no IS was used for the trichothecenes. Detection of the mycotoxins was carried out in the multiple reaction monitoring (MRM) mode. Method performance characteristics were estimated after analysis of spiked blank maize samples. Calibration curves were linear between 10 and 1000 microg/kg and the limits of detection ranged from 0.3 to 3.8 microg/kg depending on the mycotoxin. Moreover, the accuracy of the method was confirmed by comparing analytical data to certified values from reference materials for deoxynivalenol and zearalenone.

Towards smaller and faster gas chromatography–mass spectrometry systems for field chemical detection

Gas chromatography-mass spectrometry (GC-MS) is already an important laboratory method, but new sampling techniques and column heating approaches will expand and improve its usefulness for detection and identification of unknown chemicals in field settings. In order to demonstrate commercially-available technical advances for both sampling and column heating, we used solid phase microextraction (SPME) sampling of both water and air systems, followed by immediate analysis with a resistively heated analytical column and mass spectrometric detection. High-concern compounds ranging from 140 to 466 amu were analyzed to show the applicability of these techniques to emergency situations impacting public health. A field portable (about 35 kg) GC-MS system was used for analysis of water samples with a resistively heated analytical column externally mounted as a retrofit using the air bath oven of the original instrument design to heat transfer lines. The system used to analyze air samples included a laboratory mass spectrometer with a dedicated resistive column heating arrangement (no legacy air bath column oven). The combined sampling and analysis time was less than 10 min for both air and water sample types. By combining dedicated resistive column heating with smaller mass spectrometry systems designed specificallyfor use in the field, substantially smaller high performance field-portable instrumentation will be possible.

Analysis of Trichothecenes in Barley Tea and Beer by Liquid Chromatography/Tandem Mass Spectrometry

A simple method for analysis of trichothecenes [Type A: diacetoxyscirpenol, neosolaniol, HT-2 toxin, and T-2 toxin, Type B: deoxynivalenol, nivalenol, fusarenon-X, 3-acetyldeoxynivalenol, 15-acetyldeoxynivarenol] in barley tea and beer using liquid chromatography tandem mass spectrometry (LC/MS/MS) was developed. Trichothecenes were extracted with ethyl acetate-methanol (19:1). The solvent was evaporated to dryness and the residue was dissolved in water-methanol (3:1) for injection into the LC/MS/MS. The LC separation was performed with an octadecylated silica column at a flow-rate of 0.2 mL/min, using a mobile phase consisting of water, methanol and acetonitrile. MS/MS was used in multiple reaction monitoring, employing electrospray ionization (ESI-MRM). The recoveries of trichothecenes from drinks at 1 microg/L (Type A) and 10 microg/L (Type B) were 52.5-115.2% (barley tea) and 68.1-127.5% (beer). Five barley tea and ten beer samples were analyzed by this method. Trichothecenes were not detected in them. This method may have applications in quality assurance.

Simultaneous determination of major B-trichothecenes and the de-epoxy-metabolite of deoxynivalenol in pig urine and maize using high-performance liquid chromatography–mass spectrometry

A selective analytical method based on high-performance liquid chromatography (HPLC), combined with atmospheric pressure chemical ionisation (APCI-) mass spectrometry (MS), has been developed for simultaneous determination of B-trichothecenes and the major metabolites of deoxynivalenol. The method allows simultaneous analysis of nivalenol (NIV), deoxynivalenol (DON), 15-acetyldeoxynivalenol (15-AcDON), 3-acetyldeoxynivalenol (3-AcDON), fusarenon X (Fus-X) and de-epoxydeoxynivalenol (DOM-1). The method is based on one-step sample clean-up using a multifunctional MycoSep column. A linear gradient mobile phase system, consisting of water:acetonitrile:methanol (H2O:ACN:MeOH) at a flow-rate of 1 ml/min, and a Polar-RP C18 column, were utilised to obtain the best resolution of all tested compounds along with column and equilibrating within 30 min. Dexamethasone (Dex) was used as internal standard. The developed method shows good repeatability for inter- and intra-day precisions as well as good linearity of calibration curves (r2 ranged from 0.9936 to 0.9998). Average recoveries for tested compounds in both matrices have been determined ranging from 63.7 to 102.3% and limit of quantification (LOQ) ranged from 25 to 150 ng/g. The utility and practical impact of the method is demonstrated using contaminated pig urine and maize samples.

Methods for the determination of deoxynivalenol and other trichothecenes in foods

Trichothecene mycotoxins are secondary metabolites of Fusarium moulds that routinely infect cereal crops. Processing can reduce, but not eliminate, trichothecenes from cereal-based foods, and the potential presence of the trichothecenes in cereal foods poses a significant health risk to consumers. Deoxynivalenol (vomitoxin, DON) is the most common of the trichothecenes detected in cereal crops and is subject to government regulation in many countries. Sensitive (ng/g) methods for the detection of trichothecenes in cereal grains and food products are needed to protect consumers, to provide data for dietary exposure estimates, and to support research into the control of moulds and subsequent toxin production. Laboratories require simple, rugged and reliable methods for routine testing, with unequivocal identification of suspect mycotoxins. A method employing gas chromatography-negative ion chemical ionisation/mass spectrometry (GC-NICI/MS) has been developed and used for the routine determination of eight of the most significant trichothecenes in a variety of commodities. This chapter discusses GC, liquid chromatographic (LC) and supercritical fluid chromatographic methods that are currently used for the analysis of trichothecene mycotoxins.

Simple and sensitive determination of citrinin in Monascus by GC-selected ion monitoring mass spectrometry

A new method for the qualitative and quantitative analysis of citrinin in Monascus by gas-chromatography-selected ion monitoring (SIM) mass spectrometry has been developed. GC separation of citrinin in Monascus extract was achieved without the need for chemical derivatization, and could be detected as a single peak when the SIM mode selected 5 prominent fragmentations (m/z of 220, 205, 177, 105 and 91). The quantitative detection limit for citrinin was approximately 1 ppb. Finally, the GC-separated analyte from Monascus extract, at a retention time of 10.89 min, was examined by the method of pattern recognition by comparison with a citrinin standard. The results show that the 2 compounds had a 94% similarity when the SIM mode was used.

Fast methods for screening of trichothecenes in fungal cultures using gas chromatography-tandem mass spectrometry

The paper presents a fast method for trichothecene profiling and chemotaxonomic studies in species of Fusarium, Stachybotrys. Trichoderma and Memnoniella. Micro scale extracted crude Fusarium extracts were derivatised using pentafluoropropionic anhydride and analysed by gas chromatography with simultaneous full scan and tandem mass spectrometric detection. It was possible to monitor for up to four compounds simultaneous, making detection of acetyl T-2 toxin, T-2 toxin, HT-2 toxin, T-2 triol. T-2 tetraol, neosolaniol, iso-neosolaniol, scirpentriol, 4,15-diacetoxyscirpenol, 15-acetoxyscirpenol, 4-acetoxyscirpentriol, nivalenol, fusarenon-X, deoxynivalenol, 15-acetyl-deoxynivalenol and 3-acetyldeoxynivalenol possible during a 23-min GC run. A slightly modified method could detect trichothecenes produced by Stachybotrys, Memnoniella and Trichoderma, by hydrolysing crude extracts prior to derivatisation with heptafluorobuturyl imidazole. All types of derivatised extracts could be reanalysed using negative ion chemical ionisation (NICI) GC-MS for molecular mass determination and verification purposes. A retention time index could be used for correction in retention time drifts between sequences and worked both in EI+ and NICI mode.

A survey of zearalenone in corn using Romer Mycosep 224 column and high performance liquid chromatography

A survey of zearalenone (ZEA) in corn from various regions of Brazil was carried out by the analysis of 380 corn samples, of which 30 samples (7.8%) were found to be contaminated in the range of 46.7-719 micrograms/kg. ZEA was extracted with acetonitrile-water (84:16, v/v), cleaned-up on a Romer Mycosep 224 column, separated, detected and quantified by high performance liquid chromatography (HPLC). The in-house method characteristics of linearity, accuracy, precision, and detection limit were defined by means of recovery tests with spiked corn samples in the range of 35.8-716 micrograms/kg and the analysis of a naturally-contaminated sample (n = 7). The mean recovery for ZEA was 99.4% and the relative standard deviation (RSD) varied from 0.7 to 26.6% in the range studied. The method has been shown to be accurate, quick and reliable for determination of zearalenone in corn.

Simultaneous determination of trichothecene mycotoxins and zearalenone in cereals by gas chromatography-mass spectrometry

Trichothecene mycotoxins are commonly distributed in crop fields in the world, and zearalenone has been found in cereals. Rapid and accurate methods for the determination of these mycotoxins is required to prevent the intoxication of humans, and to contribute to the supply of safe foods and feeds for human and livestock. Gas chromatography-mass spectrometry (GC-MS) is a useful method for the determination of these toxins. We describe here our current GC-MS analysis for the simultaneous determination of trichothecenes and zearalenone contaminants in cereals.

Quantification of deoxynivalenol in wheat using an immunoaffinity column and liquid chromatography

A simple and accurate method to quantify the mycotoxin deoxynivalenol (DON) in wheat is described. The method uses immunoaffinity chromatography for DON isolation and liquid chromatography (LC) for toxin detection and quantification. Wheat samples are extracted in water, filtered twice and applied to an immunoaffinity column. Following a water wash, DON is eluted from the column with methanol and injected onto an LC system with a UV detector for quantification. Test performance was evaluated in terms of antibody specificity, limit of detection, percentage recovery, precision, column capacity, assay linearity and comparison with the GC-electron-capture detection (ECD) method of Tacke and Casper. Specificity of the immunoaffinity column cleanup procedure was confirmed with only DON (>80%) and its 15-C derivatives (40-50%) being recognized by the antibody while 3-C DON derivatives, nivalenol, T-2 and fusarenon-X did not bind. The limit of detection is at least 0.10 microg/g. Percentage recovery for the entire assay range averages 90% with an average relative standard deviation of 8.3%. Naturally contaminated samples showed comparable precision. Column capacity was determined to be 3.3 microg. The assay showed a high degree of linearity (r2=0.999) and an optimum assay range of 0.10 to 10.0 microg/g. Comparative analysis of 28 naturally or artificially contaminated wheat samples using DONtest-HPLC and the GC-ECD method of Tacke and Casper showed that DONtest-HPLC is a statistically significant predictor of the GC-ECD method (r2=0.982).