Stable isotope dilution analysis of the fusarium mycotoxin zearalenone

Detection of Mycotoxins in Highly Matrix-Loaded House-Dust Samples by QTOF-HRMS, IM-QTOF-HRMS, and TQMS: Advantages and Disadvantages

The analysis of (trace) contaminants in environmental samples represents an important tool for exposure assessment and for the evaluation of potential risks to human health. Currently, mass spectrometric detection using triple quadrupole (TQMS) systems is the established method of choice. However, screening methods using high resolution mass spectrometry (HRMS) find increasing application as they provide advantages such as enhanced selectivity. A complex composition of environmental samples is known to have enormous effects on mass analyzers. The present work therefore compares the impact of a highly matrix-loaded sample material like house-dust on the performance of mass spectrometric detection of the emerging indoor contaminant group of mycotoxins by quadrupole time-of-flight (QTOF) and TQMS after ultrahigh-performance liquid chromatographic separation. Furthermore, the role of ionization efficiencies of different ion sources in instrument sensitivity was compared using an electrospray ionization source and a newly developed heated electrospray ion source (Bruker VIP-HESI) during QTOF experiments. Finally, it was evaluated whether an additional dimension of separation enables increased sensitivity in QTOF-HRMS detection by applying mycotoxins in house-dust to an (trapped) ion mobility spectrometry instrument. The sensitivity of the QTOF detection was positively influenced by the application of the VIP-HESI ion source, and overall HRMS instruments provided enhanced selectivity resulting in simplified data evaluation compared to the TQMS. However, all performed experiments revealed strong signal suppression due to matrix components. QTOF results showed more severe effects, enabling a more sensitive detection of mycotoxins in house-dust by applying TQMS detection.

Determination of Urinary Mycotoxin Biomarkers Using a Sensitive Online Solid Phase Extraction-UHPLC-MS/MS Method

In the course of assessing the human exposure to mycotoxins, biomarker-based approaches have proven to be important tools. Low concentration levels, complex matrix compositions, structurally diverse analytes, and the large size of sample cohorts are the main challenges of analytical procedures. For that reason, an online solid phase extraction-ultra high-performance liquid chromatography-tandem mass spectrometry (online SPE-UHPLC-MS/MS) method was developed, allowing for the sensitive, robust, and rapid analysis of 11 relevant mycotoxins and mycotoxin metabolites in human urine. The included spectrum of analytes comprises aflatoxin M₁ (AFM₁), altenuene (ALT), alternariol monomethyl ether (AME), alternariol (AOH), citrinin (CIT) and its metabolite dihydrocitrinone (DH-CIT), fumonisin B₁ (FB₁), ochratoxin A (OTA), and zearalenone (ZEN) as well as α- and β-zearalenol (α- and β-ZEL). Reliable quantitation was achieved by means of stable isotope dilution, except for ALT, AME and AOH using matrix calibrations. The evaluation of method performance displayed low limits of detection in the range of pg/mL urine, satisfactory apparent recovery rates as well as high accuracy and precision during intra- and interday repeatability. Within the analysis of Zimbabwean urine samples (n = 50), the applicability of the newly developed method was shown. In addition to FB₁ being quantifiable in all analyzed samples, six other mycotoxin biomarkers were detected. Compared to the occurrence rates obtained after analyzing the same sample set using an established dilute and shoot (DaS) approach, a considerably higher number of positive samples was observed when applying the online SPE method. Owing to the increased sensitivity, less need of sample handling, and low time effort, the herein presented online SPE approach provides a valuable contribution to human biomonitoring of mycotoxin exposure.

Dried urine spots as sampling technique for multi-mycotoxin analysis in human urine

A simple and effective approach for HPLC-MS/MS based multi-mycotoxin analysis in human urine samples was developed by application of dried urine spots (DUS) as alternative on-site sampling strategy. The newly developed method enables the detection and quantitation of 14 relevant mycotoxins and mycotoxin metabolites, including citrinin (CIT), dihydrocitrinone (DH-CIT), deoxynivalenol (DON), fumonisin B₁ (FB₁), T-2 Toxin (T-2), HT-2 Toxin (HT-2), ochratoxin A (OTA), 2′R-ochratoxin A (2′R-OTA), ochratoxin α (OTα), tenuazonic acid and allo-tenuazonic acid (TeA + allo-TeA), zearalenone (ZEN), zearalanone (ZAN), α-zearalenol (α-ZEL), and β-zearalenol (β-ZEL). Besides the spotting procedure, sample preparation includes enzymatic cleavage of glucuronic acid conjugates and stable isotope dilution analysis. Method validation revealed low limits of detection in the range of pg/mL urine and excellent apparent recovery rates for most analytes. Stability investigation of DUS displayed no or only slight decrease of the analyte concentration over a period of 28 days at room temperature. The new method was applied to the analysis of a set of urine samples (n = 91) from a Swedish cohort. The four analytes, DH-CIT, DON, OTA, and TeA + allo-TeA, could be detected and quantified in amounts ranging from 0.06 to 0.97 ng/mL, 3.03 to 136 ng/mL, 0.013 to 0.434 ng/mL and from 0.36 to 47 ng/mL in 38.5%, 70.3%, 68.1%, and 94.5% of the samples, respectively. Additional analysis of these urine samples with an established dilute and shoot (DaS) approach displayed a high consistency of the results obtained with both methods. However, due to higher sensitivity, a larger number of positive samples were observed using the DUS method consequently providing a suitable approach for human biomonitoring of mycotoxin exposure.

Ligand-enabled ortho-C-H olefination of phenylacetic amides with unactivated alkenes

Although chelation-assisted C-H olefination has been intensely investigated, Pd(ii)-catalyzed C-H olefination reactions are largely restricted to acrylates and styrenes. Here we report a quinoline-derived ligand that enables the Pd(ii)-catalyzed olefination of the C(sp2)-H bond with simple aliphatic alkenes using a weakly coordinating monodentate amide auxiliary. Oxygen is used as the terminal oxidant with catalytic copper as the co-oxidant. A variety of functional groups in the aliphatic alkenes are tolerated. Upon hydrogenation, the ortho-alkylated product can be accessed. The utility of this reaction is also demonstrated by the late-stage diversification of drug molecules.

Multi-mycotoxin analysis using dried blood spots and dried serum spots

In this study, a rapid multi-mycotoxin approach was developed for biomonitoring and quantification of 27 important mycotoxins and mycotoxin metabolites in human blood samples. HPLC-MS/MS detection was used for the analysis of dried serum spots (DSS) and dried blood spots (DBS). Detection of aflatoxins (AFB₁, AFB₂, AFG₁, AFG₂, AFM₁), trichothecenes (deoxynivalenol, DON; DON-3-glucoronic acid, DON-3-GlcA; T-2; HT-2; and HT-2-4-GlcA), fumonisin B₁ (FB₁), ochratoxins (OTA and its thermal degradation product 2'R-OTA; OTα; 10-hydroxychratoxin A, 10-OH-OTA), citrinin (CIT and its urinary metabolite dihydrocitrinone, DH-CIT), zearalenone and zearalanone (ZEN, ZAN), altenuene (ALT), alternariols (AOH; alternariol monomethyl ether, AME), enniatins (EnA, EnA₁, EnB, EnB₁) and beauvericin (Bea) was validated for two matrices, serum (DSS), and whole blood (DBS). HPLC-MS/MS analysis showed signal suppression as well as signal enhancement due to matrix effects. However, for most analytes LOQs in the lower pg/mL range and excellent recovery rate were achieved using matrix-matched calibration. Besides validation of the method, the analyte stability in DBS and DSS was also investigated. Stability is a main issue for some analytes when the dried samples are stored under common conditions at room temperature. Nevertheless, the developed method was applied to DBS samples of a German cohort (n = 50). Besides positive findings of OTA and 2'R-OTA, all samples were positive for EnB. This methodical study establishes a validated multi-mycotoxin approach for the detection of 27 mycotoxins and metabolites in dried blood/serum spots based on a fast sample preparation followed by sensitive HPLC-MS/MS analysis. Graphical Abstract ᅟ.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry imaging of ochratoxin A and fumonisins in mold-infected food

RATIONALE

Mycotoxins are toxic secondary metabolites produced by various fungi. Their distribution within contaminated material is of high interest to obtain insight into infection mechanisms and the possibility of reducing contamination during food processing.

METHODS

Various vegetable foodstuffs were infected with fungi of the genera Fusarium and Aspergillus. The localization of the produced mycotoxins was studied by matrix-assisted laser desorption/ionization time-of flight mass spectrometry imaging (MALDI-MSI) of cryosections obtained from infected material. The results were confirmed by high-performance liquid chromatography/electrospray ionization triple quadrupole mass spectrometry (HPLC/MS/MS).

RESULTS

The mycotoxins ochratoxin A (OTA) and fumonisins of the B- and C-series (FB₁ , FB₂ , FB₃ , FB₄ , FC₁ , FC_2/3 , and FC₄ ) as well as partially hydrolyzed fumonisins (pHFB₁ , pHFB₂ , pHFB₃ , pHFC₁ , and pHFC_2/3 ) could successfully be detected by MALDI-MSI in mold-infested foodstuffs. The toxins are distributed differently in the material: OTA is co-localized with visible fungal spoilage while fumonisins could be detected throughout the whole sample.

CONCLUSIONS

This work shows the applicability of MALDI-MSI to mycotoxin analysis. It has been demonstrated that the analyzed mycotoxins are differently distributed within moldy foodstuffs. These findings show the potential of MALDI-MSI for the localization of these hazardous compounds in various plant tissues. Copyright © 2016 John Wiley & Sons, Ltd.

A comparative study of the human urinary mycotoxin excretion patterns in Bangladesh, Germany, and Haiti using a rapid and sensitive LC-MS/MS approach

An improved "dilute and shoot" LC-MS/MS multibiomarker approach was used to monitor urinary excretion of 23 mycotoxins and their metabolites in human populations from Asia (Bangladesh), Europe (Germany), and the Caribbean region (Haiti). Deoxynivalenol (DON), deoxynivalenol-3-glucuronide (DON-3-GlcA), T-2-toxin (T-2), HT-2-toxin (HT-2), HT-2-toxin-4-glucuronide (HT-2-4-GlcA), fumonisin B1 (FB1), aflatoxins (AFB1, AFB2, AFG1, AFG2, AFM1), zearalenone (ZEA), zearalanone (ZAN), their urinary metabolites α-zearalanol (α-ZEL) and β-zearalanol (β-ZEL), and corresponding 14-O-glucuronic acid conjugates (ZEA-14-GlcA, ZAN-14-GlcA, β-ZEL, α/β-ZEL-14-GlcA), ochratoxin A (OTA), and ochratoxin alpha (OTα) as well as enniatin B (EnB) and dihydrocitrinone (DH-CIT) were among these compounds. Eight urinary mycotoxin biomarkers were detected (AFM1, DH-CIT, DON, DON-GLcA, EnB, FB1, OTA, and α-ZEL). DON and DON-GlcA were exclusively detected in urines from Germany and Haiti whereas urinary OTA and DH-CIT concentrations were significantly higher in Bangladeshi samples. AFM1 was present in samples from Bangladesh and Haiti only. Exposure was estimated by the calculation of probable daily intakes (PDI), and estimates suggested occasional instances of toxin intakes that exceed established tolerable daily intakes (TDI). The detection of individual mycotoxin exposure by biomarker-based approaches is a meaningful addition to the classical monitoring of the mycotoxin content of the food supply.

Preparation of 13C-labelled cis-zearalenone and its application as internal standard in stable isotope dilution analysis

Pure U-[13C18]-labelled cis-zearalenone (cis-ZEA) has been prepared and characterised as internal standard (ISTD) for a reliable quantification of cis-ZEA in contaminated food and feed products. The cis-isomer of the naturally trans-configurated Fusarium mycotoxin zearalenone is often neglected. However, isomerisation easily occurs by exposure of ZEA to (UV-)light. Thus, the applicability of the new cis-ZEA ISTD was demonstrated in a long-term isomerisation study comparing naturally trans-ZEA-contaminated edible oil with spiked edible oil. To estimate the benefits of the newly prepared cis-ZEA ISTD, various approaches to quantify cis-ZEA by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) were compared. As a result, a significant bias was revealed if no appropriate cis-ZEA standards are used. Furthermore, the new ISTD was applied to the analysis of 15 edible oils by stable isotope dilution analysis in combination with HPLC-electrospray ionisation-MS/MS. One of the maize germ oils showed the presence of cis-ZEA above LOD (≯0.3 μg/kg), whereas two out of 15 maize germ oils were found to be contaminated with trans-ZEA (range 17.0-31.0 μg/kg).

Advanced hyphenated chromatographic-mass spectrometry in mycotoxin determination: current status and prospects

Mass spectrometric techniques are essential for advanced research in food safety and environmental monitoring. These fields are important for securing the health of humans and animals, and for ensuring environmental security. Mycotoxins, toxic secondary metabolites of filamentous fungi, are major contaminants of agricultural products, food and feed, biological samples, and the environment as a whole. Mycotoxins can cause cancers, nephritic and hepatic diseases, various hemorrhagic syndromes, and immune and neurological disorders. Mycotoxin-contaminated food and feed can provoke trade conflicts, resulting in massive economic losses. Risk assessment of mycotoxin contamination for humans and animals generally depends on clear identification and reliable quantitation in diversified matrices. Pioneering work on mycotoxin quantitation using mass spectrometry (MS) was performed in the early 1970s. Now, unambiguous confirmation and quantitation of mycotoxins can be readily achieved with a variety hyphenated techniques that combine chromatographic separation with MS, including liquid chromatography (LC) or gas chromatography (GC). With the advent of atmospheric pressure ionization, LC-MS has become a routine technique. Recently, the co-occurrence of multiple mycotoxins in the same sample has drawn an increasing amount of attention. Thus, modern analyses must be able to detect and quantitate multiple mycotoxins in a single run. Improvements in tandem MS techniques have been made to achieve this purpose. This review describes the advanced research that has been done regarding mycotoxin determination using hyphenated chromatographic-MS techniques, but is not a full-circle survey of all the literature published on this topic. The present work provides an overview of the various hyphenated chromatographic-MS-based strategies that have been applied to mycotoxin analysis, with a focus on recent developments. The use of chromatographic-MS to measure levels of mycotoxins, including aflatoxins, ochratoxins, patulin, trichothecenes, zearalenone, and fumonisins, is discussed in detail. Both free and masked mycotoxins are included in this review due to different methods of sample preparation. Techniques are described in terms of sample preparation, internal standards, LC/ultra performance LC (UPLC) optimization, and applications and survey. Several future hyphenated MS techniques are discussed as well, including multidimensional chromatography-MS, capillary electrophoresis-MS, and surface plasmon resonance array-MS.

Simultaneous multiple mycotoxin quantification in feed samples using three isotopically labeled internal standards applied for isotopic dilution and data normalization through ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry

RATIONALE

Mycotoxins are typically present in grain and are also concentrated in distillers dried grains with solubles (DDGS), common feed ingredients for food animals. The diversity of mycotoxins and feed matrices has made the routine detection and quantification of mycotoxins in feed both complex and prohibitively expensive.

METHODS

Ultra-performance liquid chromatography/electrospray ionization triple quadrupole detection (UPLC/ESI-TQD) (tandem mass spectrometry, MS/MS) with (13) C-labeled isotopic dilution was used to analyze internal standard isotopologues of three mycotoxin molecules, as well as 29 other structurally differing mycotoxin molecules from four common feed matrices: corn, wheat, barley, or DDGS. Mycotoxins were extracted via a single-step procedure using a mixture of acetonitrile/water/formic acid. Labeled isotopologues were used as a surrogate to account for extraction quality and as internal standards for the evaluation of the feed matrix signal suppression/enhancement (SSE) contributed by each mycotoxin and by each matrix. The SSE was corrected by matrix-matched calibration with blank certified reference feed material.

RESULTS

The limits of detection for individual mycotoxins in buffer ranged from 0.01 to 206.7 µg/mL but could increase by up to four times depending on the matrix effect. The accuracy and precision were enhanced by the use of isotopically labeled standards. The recoveries were somewhat negatively affected by the SSE contributed by each matrix. Each mycotoxin was successfully detected and assigned to one of four SSE categories: high (-66%), intermediate (-48%), low (-19%) signal suppression and signal enhancement (> +300%).

CONCLUSIONS

An improved LC/MS method was validated, which offers a practical and economical means for large-scale detection and quantification of multiple mycotoxins in common animal-feed matrices, including DDGS.

New approach via gene knockout and single-step chemical reaction for the synthesis of isotopically labeled fusarin c as an internal standard for the analysis of this fusarium mycotoxin in food and feed samples

The gold standard for quantitation of contaminants with high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) is the use of isotopically labeled standards. Herein, we report a new strategy for the synthesis of isotopically labeled 21-d3-fusarin C via a genetically modified Fusarium strain, followed by a one-step derivatization reaction. Fusarin C is a Fusarium mycotoxin, which is mutagenic after metabolic activation. Its occurrence has been demonstrated recently in corn-based samples, but up to now, little is known about the contamination of other grain samples. To collect further data, the quantitation method was enhanced by application of the 21-d3-fusarin C and the use of a QTRAP 5500 mass spectrometer. This new method has a limit of detection (LOD) of 1 μg/kg, a limit of quantitation (LOQ) of 4 μg/kg, and a recovery rate of 99%. A total of 21 corn samples and 13 grain samples were analyzed, with resulting fusarin C levels varying from not detectable to 24.7 μg/kg.

Stable isotope dilution assay for the accurate determination of mycotoxins in maize by UHPLC-MS/MS

A fast, easy-to-handle and cost-effective analytical method for 11 mycotoxins currently regulated in maize and other cereal-based food products in Europe was developed and validated for maize. The method is based on two extraction steps using different acidified acetonitrile–water mixtures. Separation is achieved using ultrahigh-performance liquid chromatography (UHPLC) by a linear water–methanol gradient. After electrospray ionisation, tandem mass spectrometric detection is performed in dynamic multiple reaction monitoring mode. Since accurate mass spectrometric quantification is hampered by matrix effects, uniformly [(13)C]-labelled mycotoxins for each of the 11 compounds were added to the sample extracts prior to UHPLC-MS/MS analysis. Method performance parameters were obtained by spiking blank maize samples with mycotoxins before as well as after extraction on six levels in triplicates. The twofold extraction led to total recoveries of the extraction steps between 97% and 111% for all target analytes, including fumonisins. The [(13)C]-labelled internal standards efficiently compensated all matrix effects in electrospray ionisation, leading to apparent recoveries between 88% and 105% with reasonable additional costs. The relative standard deviations of the whole method were between 4% and 11% for all analytes. The trueness of the method was verified by the measurement of several maize test materials with well-characterized concentrations. In conclusion, the developed method is capable of determining all regulated mycotoxins in maize and presuming similar matrix effects and extraction recovery also in other cereal-based foods.

Determination of aflatoxins in animal feeds by liquid chromatography/tandem mass spectrometry with isotope dilution

The objective of the present study is to develop a simple, fast method for detection of aflatoxins in animal feeds. Simultaneous quantitation of four aflatoxins (AFB(1), AFB(2), AFG(1) and AFG(2)) in animal feeds was achieved in a single liquid chromatography/tandem mass spectrometry (LC/MS/MS) run. The solid-phase extraction cleanup step is eliminated with the stable isotope dilution method. Matrix effects were observed and overcome by isotope dilution. The method was tested in a variety of animal feed matrices and proved to be accurate and reliable. Method ruggedness tests resulted in recoveries of 78% to 122% with an intra-day assay precision of 2% to 15% and an inter-day assay precision of 3% to 17%. These results indicate that this method is suitable for quantitation of aflatoxins in animal feeds.

Zearalenone occurrence and human exposure

Among the mycotoxins zearalenone (ZEA) is of interest because of the oestrogenic effects that it, and certain of its metabolites possess. The fungi that produce ZEA are found worldwide, particularly in cereal grains and derived products. This has prompted many surveys to detect these compounds in commodities and foods. As a result, the widespread occurrence of ZEA in foods is well documented. Previous summaries including extensive reports by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the European Commission's Scientific Cooperation on Questions Relating to Food (SCOOP), and others, have provided significant information on the occurrence of ZEA in commodities and foods. Publication of occurrence data has continued at a rapid pace, and certain of that data, as well as highlights from previous intake and exposure assessments, are summarised herein. Comparing estimates of intake (exposure) with previous estimates of tolerable daily intakes, suggests that, for many of the countries where exposure assessments have been done, the populations are exposed to levels that would be considered safe. The situation may be different in populations that consume large quantities of foods that are susceptible to contamination, or in instances where contamination is atypically high. For much of the world estimates of exposure have not been reported, meaning that for much of the world, the true extent of the relevance of ZEA to human health remains uncharacterised.

Large-scale production of selected type A trichothecenes: the use of HT-2 toxin and T-2 triol as precursors for the synthesis of d 3-T-2 and d 3-HT-2 toxin

The type A trichothecenes T-2 and HT-2 toxins are toxic secondary metabolites produced by fungi of the Fusarium genus. Their occurrence in cereals, especially in oats, implies health risks for the consumer. Therefore, it is an important task to develop selective and sensitive methods for the analysis of T-2 and HT-2 toxins, and to undertake further studies on their stability and toxicity. Although most toxins are commercially available, their high prices are the limiting factor on the realization of these experiments. Thus, we developed a method for large-scale production of T-2 and HT-2 toxin as well as T-2 triol and T-2 tetraol. T-2 toxin was obtained in gram quantities by biosynthetic production with cultures of F. sporotrichioides. As HT-2 toxin was only formed as a by-product, and T-2 triol and T-2 tetraol were not generated, these compounds were produced by alkaline hydrolysis of T-2 toxin. Separation and isolation of crude toxins was achieved by fast centrifugal partition chromatography (FCPC), which is an efficient tool for the large-scale purification of natural products. Using this fast and yield effective technique, several hundred milligrams of HT-2 toxin, T-2 triol, and T-2 tetraol were obtained. Subsequent, HT-2 toxin and T-2 triol were used for the large-scale synthesis of isotope-labeled T-2 and HT-2 toxin, respectively. Using these standards, an isotope dilution-(ID)-HPLC-MS/MS method for the quantification of T-2 and HT-2 toxin in different matrices was developed.

Developments in mycotoxin analysis: an update for 2007-2008

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2007 and mid-2008. It covers the major mycotoxins: aflatoxins, Alternaria toxins, cyclopiazonic acid, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Some aspects of natural occurrence, particularly if linked to novel aspects of analytical methods, are also included. The review demonstrates the rise of LC-MS methods, the continuing interest in developing alternative and rapid methods and the modification of well-established mycotoxin analytical methods by individual laboratories to meet their own requirements.

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.

Quantification of zearalenone in various solid agroenvironmental samples using D6-zearalenone as the internal standard

Because of its pronounced estrogenicity, zearalenone may be of concern not only in the aqueous but also in the terrestrial environment. Therefore, we developed several analytical methods to quantify zearalenone in different solid matrices of agroenvironmental relevance (i.e., plant organs, soil, manure, and sewage sludge). The use of D(6)-zearalenone as the internal standard (IS) was essential to render the analytical method largely matrix-independent because it compensated for target analyte losses during extract treatment and ion suppression during ionization. Soil and sewage sludge samples were extracted with Soxhlet, whereas plant material and manure samples were extracted by liquid solvent extraction at room temperature. Absolute recoveries for zearalenone were 70-104% for plant materials, 105% for soil, 76% for manure, and 30% for sewage sludge. Relative recoveries ranged from 86 to 113% for all matrices, indicating that the IS was capable to largely compensate for losses during analysis. Ion suppression, between 8 and 74%, was in all cases compensated by the IS but influenced the method quantification levels. These were 3.2-26.2 ng/g(dryweightdw) for plant materials, 0.7 ng/g(dw) for soil, 12.3 ng/g(dw) for manure, and 6.8 ng/g(dw) for sewage sludge. Plant material concentrations varied from 86 ng/g(dw) to more than 16.7 microg/g(dw), depending on the organ and crop. Soil concentrations were between not detectable and 7.5 ng/g(dw), depending on the sampling depth. Zearalenone could be quantified in all manure samples in concentrations between 8 and 333 ng/g(dw). Except for two of the 85 investigated sewage sludge samples, zearalenone concentrations were below quantification limit.