[Determination of zearalenone and α-zearalenol in vegetable oil and grain products by C_(18)-Al_2O_3 solid phase extraction column purification coupled with ultra-performance liquid chromatography tandem mass spectrometry].

OBJECTIVE: To develop a method for simultaneous determination of zearalenone( ZEN) and α-zearalenol( α-ZEL) in vegetable oil and grain products by solid phase extraction column purification coupled with ultra-performance liquid chromatography tandem mass spectrometry. METHODS: Firstly, ZEN and α-ZEL in grain products were extracted by hexane/ethyl acetate( 50 : 50, V/V), and then extracted as vegetable oil by acetonitrile-water solution( 90: 10, V/V), and purified by C_(18)-Al_2O_3 solid phase extraction column. ZEN and α-ZEL was separated by UPLC with acetonitrile-water gradient elution on C_(18) column( 2. 1 mm × 100 mm, 1. 6 µm), and qualified/quantified by mass spectrometry with ESI negative MRM mode with ~(13)C_(18)-zearalenone as internal standard. RESULTS: The linearity of ZEN and α-ZEL ranged from 1. 0-500 ng/mL. The limit of detection for ZEN and α-ZEL in vegetable oil and grain products was 0. 3 and 0. 2 µg/kg, respectively. The limit of quantification for ZEN and α-ZEL in vegetable oil and grain products was 1. 0 and 0. 5 µg/kg. The average recoveries of ZEN and α-ZEL for spiked samples of 1. 0-100 µg/kg were 93. 5%-108. 0% and 92. 0%-105. 0%. The relative standard deviations of ZEN and α-ZEL were 3. 2%-8. 5% and 4. 6%-7. 8%( n = 6). 55 samples sold in Hangzhou supermarkets were analyzed. ZEN was detected in all corn germ oil with median and maximum contents of 126. 2 and 453. 1 µg/kg. α-ZEL was detected in 50% corn germ oil with median and maximum contents of 2. 0 and 5. 0µg/kg. CONCLUSION: The method possesses several advantages including sensitivity, precision, good efficiency of purification, simplicity and economy, and it is applicable to the batch analysis of zearalenone and α-zearalenol in vegetable oil and grain products.

Effect of rainfall timing and tillage on the transport of steroid hormones in runoff from manure amended row crop fields.

Runoff generated from livestock manure amended row crop fields is one of the major pathways of hormone transport to the aquatic environment. The study determined the effects of manure handling, tillage methods, and rainfall timing on the occurrence and transport of steroid hormones in runoff from the row crop field. Stockpiled and composted manure from hormone treated and untreated animals were applied to test plots and subjected to two rainfall simulation events 30days apart. During the two rainfall simulation events, detection of any steroid hormone or metabolites was identified in 8-86% of runoff samples from any tillage and manure treatment. The most commonly detected hormones were 17ß-estradiol, estrone, estriol, testosterone, and α-zearalenol at concentrations ranging up to 100-200ngL-1. Considering the maximum detected concentrations in runoff, no more than 10% of the applied hormone can be transported through the dissolved phase of runoff. Results from the study indicate that hormones can persist in soils receiving livestock manure over an extended period of time and the dissolved phase of hormone in runoff is not the preferred pathway of transport from the manure applied fields irrespective of tillage treatments and timing of rainfall.

Optimisation and validation of a new analytical method for the determination of four natural and synthetic hormones using LC-ESI-MS/MS.

A rapid liquid chromatographic-tandem mass spectrometric method was developed for the simultaneous determination of four natural and synthetic hormone residues (progesterone, testosterone, trenbolone acetate and zeranol) in animal tissue samples. Sample preparation was optimised to minimise time and solvent consumption. Meat samples were mechanically homogenised and digested in a procedure that gave similar recoveries to those enzymatically hydrolysed by Helix pomatia. Efficient extraction was achieved using acidified acetonitrile (1% acetic acid). Chromatographic conditions were optimised to minimise matrix effects. Analytes were separated using a C18 column with gradient elution using ammonium formate solution in methanol (MeOH)/water (1:9) and MeOH mobile phases. Finally, residues were qualitatively and quantitatively determined by electrospray ionisation tandem mass spectrometry in multiple reaction monitoring mode. Different parameters for LC-MS/MS (e.g., declustering potential and collision energy) were optimised using API 6500QT; all analytes were measured using positive-mode electrospray ionisation (ESI+) except zeranol which was measured in negative mode (ESI-). Due to LC-MS/MS signal enhancement/suppression, the determination of hormones was based on matrix-matched standard calculations. The method was validated for the four hormones on meat samples at different fortification levels and showed accepted performance criteria according to European Commission Decision 2002/657/EC. Decision limits and detection capabilities were estimated for all analytes.

Sorption, uptake, and biotransformation of 17ß-estradiol, 17α-ethinylestradiol, zeranol, and trenbolone acetate by hybrid poplar.

Hormonally active compounds may move with agricultural runoff from fields with applied manure and biosolids into surface waters where they pose a threat to human and environmental health. Riparian zone plants could remove hormonally active compounds from agricultural runoff. Therefore, sorption to roots, uptake, translocation, and transformation of 3 estrogens (17ß-estradiol, 17α-ethinylestradiol, and zeranol) and 1 androgen (trenbolone acetate) commonly found in animal manure or biosolids were assessed by hydroponically grown hybrid poplar, Populus deltoides x nigra, DN-34, widely used in riparian buffer strips. Results clearly showed that these hormones were rapidly removed from 2 mg L(-1) hydroponic solutions by more than 97% after 10 d of exposure to full poplar plants or live excised poplars (cut-stem, no leaves). Removals by sorption to dead poplar roots that had been autoclaved were significantly less, 71% to 84%. Major transformation products (estrone and estriol for estradiol; zearalanone for zeranol; and 17ß-trenbolone from trenbolone acetate) were detected in the root tissues of all 3 poplar treatments. Root concentrations of metabolites peaked after 1 d to 5 d and then decreased in full and live excised poplars by further transformation. Metabolite concentrations were less in dead poplar treatments and only slowly increased without further transformation. Taken together, these findings show that poplars may be effective in controlling the movement of hormonally active compounds from agricultural fields and avoiding runoff to streams.

Evaluation of the combination of a dispersive liquid-liquid microextraction method with micellar electrokinetic chromatography coupled to mass spectrometry for the determination of estrogenic compounds in milk and yogurt.

In this work, the suitability of a methodology based on dispersive liquid-liquid microextraction (DLLME) has been evaluated for the extraction of four endoestrogens (estriol, 17α-estradiol, 17ß-estradiol, and estrone), an exoestrogen (17α-etynylestradiol), and a mycotoxin (zearalenone), together with some of their major metabolites (2-methoxyestradiol, α-zearalanol, ß-zearalanol, α-zearalenol, and ß-zearalenol) from different types of milk (whole and skimmed cow milk and semiskimmed goat milk) and whole natural yogurt. The methodology includes a previous protein precipitation with acidified ACN and a defatting step with n-hexane. Separation of the analytes, determination, and quantification were developed by MEKC coupled to ESI-MS using a BGE containing an aqueous solution of ammonium perfluorooctanoate as MS friendly surfactant. Calibration, precision, and accuracy studies of the described DLLME-MEKC-MS/MS method were evaluated obtaining a good linearity and LODs in the low micrograms per liter range.

Development and application of an immunoaffinity column enzyme immunoassay for mycotoxin zearalenone in complicated samples.

The zearalenone (ZEA) monoclonal antibody (mAb) 2D3, one of the highest sensitivity antibodies, was developed. Based on this mAb, it was established of an immunoaffinity column (IAC) coupled with an indirect competitive enzyme-linked immunosorbent assay (icELISA). After optimization, the icELISA allowed an IC50 against ZEA of 0.02 µg L(-1). The mAb 2D3 exhibited a high recognition of ZEA (100%) and ß-zearalenol (ß-ZOL, 88.2%). Its cross-reactivity with α-zearalenol (α-ZOL) and ß-zearalanol (ß-ZAL) were found to be 4.4% and 4.6%, respectively. The IAC-icELISA method was employed to analyze ZEA contamination in food samples, compared with high-performance liquid chromatography (HPLC). The spiked assay for ZEA demonstrated the considerable recoveries for IAC-icELISA (83-93%) and HPLC (94-108%) methods. Results showed that the mAb 2D3 and IAC-icELISA method posed potential applications in sensitively determination of ZEA in maize.

Liquid chromatography incorporating ultraviolet and electrochemical analyses for dual detection of zeranol and zearalenone metabolites in mouldy grains.

BACKGROUND: Zeranol (Z) is a semi-synthetic mycotoxin that is used in some countries as a growth-promoting agent in livestock. In view of the known oestrogenic actions by Z and certain Z analogues, significant concerns exist with regard to the presence of Z residues in human foods and the potential for untoward effects, including carcinogenicity within the reproductive system. In order to confirm that foods are free from harmful Z residues, regulators need a quick and reliable analytical method that can be used for routine confirmation of Z-positive samples identified by enzyme-linked immunosorbent assay (ELISA) screening. In this study the authors have developed and validated a simple and rapid high-performance liquid chromatography method incorporating ultraviolet (UV) absorbance (wavelength 274 nm) and electrochemical (EC) dual-mode detection for simultaneous determination of Z-related mycotoxins produced from mouldy grain matrices, including rice, soybean and corn flakes. RESULTS: Recoveries for all analytes were around 80% and the limits of detection ranged from 10 to 25 ng mL(-1) for UV and from 50 to 90 ng mL(-1) for EC detection with good accuracy and reproducibility. Differential profiles and occurrence rates of Z, ß-zearalenol, ß-zearalanol and α-zearalenol in naturally moulded grain matrices were observed, indicating different metabolite patterns and possibly grain-specific effects of mycotoxin exposure for humans and animals. The strength of this dual detection method lies in its selectivity characterised by a carbon screen-printed electrode such that aflatoxin interference is precluded. CONCLUSION: The combined dual detection technique affords quick and reliable semi-confirmative and quantitative information on multiple types of Z analogues in mouldy grains without the necessity of using expensive mass spectrometry. The method is considered a superior supplement to ELISA, which only screens total Z immunoreactivity.

Determination of zearalenone and its metabolites in endometrial cancer by coupled separation techniques.

This study presents a selective method of isolation of zearalenone (ZON) and its metabolite, α-zearalenol (α-ZOL), in neoplastically changed human tissue by accelerated solvent and ultrasonic extractions using a mixture of acetonitrile/water (84/16% v/v) as the extraction solvent. Extraction effectiveness was determined through the selection of parameters (composition of the solvent mixture, temperature, pressure, number of cycles) with tissue contamination at the level of nanograms per gram. The produced acetonitrile/water extracts were purified, and analytes were enriched in columns packed with homemade molecularly imprinted polymers. Purified extracts were determined by liquid chromatography (LC) coupled with different detection systems (diode array detection--DAD and mass spectrometry--MS) involving the Ascentis RP-Amide as a stationary phase and gradient elution. The combination of UE-MISPE-LC (ultrasonic extraction--molecularly imprinted solid-phase extraction--liquid chromatography) produced high (R≈95-98%) and repeatable (RSD<3%) recovery values for ZON and α-ZOL.

Quantitative screening of stilbenes and zeranol and its related residues and natural precursors in veal liver by gas chromatography-mass spectrometry.

An existing gas chromatography-mass spectrometry-based quantitative screening method for the regulatory analysis of the resorcylic acid lactones zeranol, taleranol, and zearalanone and the stilbene anabolic steroids diethylstilbestrol and dienestrol was extended to include natural precursors of zeranol (zearalenone, alpha-zearalenol, and beta-zearalenol) in veal liver. No changes in sample preparation were required; the instrumental conditions were selected to effect a suitable chromatographic separation and detection of the analytes. Validation experiments were performed to verify the performance and applicability of the extended method for the quantitative screening of the original and additional analytes in veal liver in the concentration range from 0.5 to 2.0 microg/kg. The limits of detection were 0.08-0.19 microg/kg. The limits of quantitation were 0.27-0.64 microg/kg. Recoveries were 29-67%. Combined relative measurement uncertainty estimates were 6-21%.

Direct determination of the estrogenic compounds 8-prenylnaringenin, zearalenone, alpha- and beta-zearalenol in beer by liquid chromatography-mass spectrometry.

A novel LC-ESI-MS method for the simultaneous determination of four of the most significant estrogenic compounds naturally occurring in beer, 8-prenylnaringenin (8-PN), zearalenone (ZON), alpha-zearalenol (alpha-ZOL) and beta-zearalenol (beta-ZOL) which requires minimal sample preparation was developed using a chemometric approach. Experimental design was applied to assess the effects of the LC-ESI-MS parameters (mobile phase flow rate, drying gas flow, nebuliser pressure and capillary potential) on the obtained signal and to optimize the values in order to provide maximum sensitivity and detectability. The proposed method is simple, consisting only of degassing the beer and diluting with water (1:1, v/v) before injection. Comparison between the two internal standards used, zearalanone (ZAN) and 4,2'-dihydroxychalcone (4,2'-DHC), showed that ZAN performs better as internal standard not only for the mycotoxins but for 8-PN as well, giving lower % RSDs. Under inter-day conditions mean recoveries were 107% for ZON, 87.8% for alpha-ZOL, 72.8% for beta-ZOL, and 77.5% for 8-PN. The corresponding % RSDs ranged between 5.0 and 8.0. The method limits of detection were 1.3, 1.4, 1.0 and 0.8 ng mL(-1) for ZON, alpha-ZOL, beta-ZOL and 8-PN, respectively. The method was applied to 15 beer samples obtained from local supermarkets and the concentration of the phytoestrogen 8-PN in beer ranged between <0.8 and 38.6 ng mL(-1), while neither ZON nor its metabolites, alpha-ZOL and beta-ZOL, were detected.

Survey of maize from south-western Nigeria for zearalenone, alpha- and beta-zearalenols, fumonisin B1 and enniatins produced by Fusarium species.

A survey for the natural occurrence of Fusarium mycotoxins in maize for human consumption in four south-western states of Nigeria using High Performance Liquid Chromatography coupled with Mass Spectroscopy (HPLC/MS) showed that 93.4% of the samples were contaminated with zearalenone (ZON), alpha- and beta-zearalenols (alpha- and beta-ZOL), fumonisin B(1) (FB(1)) or enniatins (ENNs). The fractions of contaminated samples were 73% for FB(1) (mean:117 microg kg(-1), range:10-760 microg kg(-1)); 57% for ZON (mean:49 microg kg(-1), range:115-779 microg kg(-1)) and 13% for alpha-ZOL (mean: 63.6 microg kg(-1), range:32-181 microg kg(-1)), while ENNs A1, B and B(1) were present in 3, 7 and 3% of the samples respectively. There was no beta-ZOL present above the quantification limits of 50 microg kg(-1). Only the FB(1) content was significantly different at the 95% confidence level among the four states. The Fusarium species most frequently isolated from maize seeds were F. verticillioides (70%), followed by F. sporotrichioides (42%), F. graminearum (30%), F. pallidoroseum (15%), F. compactum (12%), F. proliferatum (12%), F. equiseti (9%), F. acuminatum (8%) and F. subglutinans (4%). This is the first report of the occurrence of alpha-zearalenol and enniatins in Nigerian maize.

Analytical methods for the determination of zeranol residues in animal products: a review.

Analytical methods for zeranol residues are reviewed. Zeranol was a widely used as an anabolic promoter, and it could give rise to very low residues in the edible tissues of food animals. Zeranol was officially banned in Europe due to safety concerns because of its potential carcinogenic and endocrine-disrupting biological activity. A few analytical methods for determination of zeranol are reported in the literature and most of the methods such as thin-layer chromatography (TLC), gas chromatography-mass spectrometry (GC/MS), high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC/MS) and immunoassay are reviewed in this paper. Specific aspects of analysing zeranol such as sample selection, sample handling, method selection and chromatographic conditions are discussed. The instrumental methods such as LC/MS and GC/MS provide sensitive and specific techniques, but are very laborious and expensive. These methods are suitable for confirmation but not for screening of large numbers of samples. A rapid, sensitive and specific assay is needed to detect positive samples in routine analysis, and immunoassay offers practical advantages over the conventional instrumental methods in rapid analysis of zeranol residues. Immunochemical methods such as enzyme-linked immunoabsorbant assay (ELISA) are simple, rapid and cost-effective, with adequate sensitivity and specificity to detect small molecules. This review can be considered as a basis for further research aimed at identifying the most efficient approaches for the analysis of zeranol.

Modification of mRNA expression after treatment with anabolic agents and the usefulness for gene expression-biomarkers.

With this feasibility study a first step towards a new monitoring system for hormonal treatments was done. Screening of regulation and function of anabolic sex steroids via modified gene expression of mRNA in various tissues could be a new approach to trace treatments with unknown drugs or newly combined cocktails. In the study, uterus, liver and muscle tissue from 24 cycling heifers were taken after the animals were treated either with Melengestrol Acetate (MGA), Finaplix-H (200 mg Trenbolone Acetate) or Ralgro (36 mg Zeranol) for 56 days. In every treatment group always two heifers were given 1-fold, 3-fold and 10-fold doses of the standard preparation, the control group without any treatment consisted of two animals. The different tissue gene expression profiles were investigated via the candidate gene approach. Totally 57 candidate genes were selected according to their functionality by screening the actual literature and composed to functional groups: angiogenesis, apoptosis, cell cycle, endocrine factors, energy metabolism, inflammatory factors, muscle function, oncogenes, protein metabolism and transcription factors. Gene expression was measured using quantitative real-time RT-PCR (qRT-PCR) technology. From 24 tested candidate genes in the liver, 17 showed a significant regulation. Eight genes were influenced by MGA, 9 by Finaplix-H, and 4 by Ralgro. For the muscle tissue 19 genes were tested with the result that in the neck muscle 11 genes were regulated and in the hind limb muscle 8 genes. In the neck 5 genes were affected by MGA, 6 by Finaplix-H and 3 by Ralgro. Only 2 genes were influenced by MGA in the hind limb muscle. Finaplix-H affected 6 and Ralgro 4 genes. In the uterus 29 target genes were tested and 13 were significantly influenced by the anabolic sex steroids. Under Finaplix-H treatment eight target genes were regulated and Ralgro and MGA showed a significant regulation in four target genes. The highest gene expression changes under anabolic treatment were observed in the uterus. The analyzed genes showed significant regulations but further studies, testing different animal husbandry conditions will be needed to identify meaningful expression patterns for the different tissues. With the investigation of the regulation and possible function of anabolic sex steroids via gene expression, a preparatory work for the development of an expression pattern for drug screening was made.

Multiresidue determination of zeranol and related compounds in bovine muscle by gas chromatography/mass spectrometry with immunoaffinity cleanup.

A gas chromatography/mass spectrometry (GC/MS) method with immunoaffinity cleanup was developed for the determination of zeranol and related compounds, taleranol, zearalanone, and alpha-zearalenol in bovine muscle. Muscle samples were extracted with methanol and cleaned up with immunoaffinity chromatography (IAC) columns containing monoclonal antibodies raised against zeranol coupled to CNBr-activated Sepharose 4B. After derivatization, the compounds were analyzed by GC/MS. The dynamic column capacities for zeranol, taleranol, zearalanone, and alpha-zearalenol were 2639.7, 2840.3, 2731.5, and 2736.3 ng/mL Sepharose gel, respectively. The limits of detection and quantification were 0.5 and 1.0 ng/g, respectively, for all 4 compounds. Mean recoveries were 79.6-110.7% with coefficients of variation of 3.2-11.4% at spiked levels of 1.0-5.0 ng/g. This IAC-GC/MS method may be used for the determination of zeranol, taleranol, zearalanone, and alpha-zearalenol residues in bovine muscle, and possibly other tissues.

Hormone contents in peripheral tissues after correct and off-label use of growth promoting hormones in cattle: effect of the implant preparations Filaplix-H, Raglo, Synovex-H and Synovex Plus.

Certain hormonal growth promoters are licensed in several beef producing countries outside the European Union (EU). Use in compliance with Good Veterinary Practice is mandatory. As risk assessment of hormone residues in animal tissues up to now has neglected potential off-label use, the present study dealt with two topics: 1) multiple treatment with the implant preparations Finaplix-H (200 mg trenbolone acetate), Ralgro (36 mg zeranol) and Synovex-H (200 mg testosterone propionate plus 20 mg estradiol benzoate) in heifers (1-fold, 3-fold and 10-fold dose), and 2) non-approved treatment of female veal calves (1-fold dose of Synovex-H or Synovex Plus with 200 mg trenbolone acetate plus 28 mg estradiol benzoate). Residues of estradiol-17beta, estradiol-17alpha, estrone and testosterone, trenbolone-17beta, trenbolone-17alpha and trendione or zeranol, respectively, were measured in loin, liver, kidney and peri-renal fat by high performance liquid chromatography/enzyme immunoassay (HPLC/EIA) after liquid-liquid extraction and solid-phase clean-up. The hormone residues in the multiple-dose experiments were dose-dependent and partially exceeded the threshold values: in the liver in one animal after 3-fold dose and in two animals after 10-fold dose of Finaplix-H, and in the liver and kidney after 3-fold and 10-fold dose of Synovex-H. Mean hormone residues in calves were mainly below those of heifers and did not infringe threshold values.

Determination of mycotoxins produced by Fusarium isolates from banana fruits by capillary gas chromatography and high-performance liquid chromatography.

A method of analysis for trichothecenes (nivalenol, deoxynivalenol, 3- and 15-acetyldeoxynivalenol, diacetoxyscirpenol, neosolaniol, T-2 tetraol, T-2 and HT-2 toxins), zearalenone and zearalenols, and another method for determination of fumonisin B1 are described and applied to cultures of Fusarium isolated from bananas. Both methods were adapted from different techniques of extraction, clean-up and determination of these mycotoxins. The first method involves extraction with methanol-1% aqueous sodium chloride, clean-up of extracts by partition with hexane and dichloromethane, additional solid reversed-phase clean-up and analysis of two eluates by both high-performance liquid chromatography with ultraviolet detection and capillary gas chromatography. The method for fumonisin B1 implies extraction with aqueous methanol, concentration, clean-up with water and methanol on Amberlite XAD-2 column, formation of a fluorescent 4-fluoro-7-nitrobenzofurazan derivative and analysis by high-performance liquid chromatography with fluorescence detection. Both procedures give good limits of detection and recoveries, and are considered suitable for the detection and quantification of the studied toxins in corn and rice cultures of Fusarium spp. isolated from banana fruits.

Thin-layer chromatographic detection of zeranol and estradiol in fortified plasma and tissue extracts with Fast Corinth V.

In an attempt to improve sensitivity of thin-layer chromatographic (TLC) analysis and selectivity of visualizing agents for detection of estrogenic anabolic hormones, several dyes were screened for their chromogenic interactions with estrone, estradiol, diethylstilbestrol (DES), zeranol (zearalanol), zearalanone, and mycotoxins, zearalenone and zearalenol. Fast Corinth V salt was selected for its relatively high sensitivity. These anabolic compounds were separated by TLC and visualized with Corinth V and the results compared to iodine and starch visualization. Fortified bovine plasma and tissues (kidney, liver and muscle) and chicken muscles were analyzed after a clean-up procedure using solid-phase dual columns of alumina and anion-exchange resin. Iodine-starch clearly detected 4 ng of estradiol and DES while zeranol and zearalenone were detected at higher levels (10 ng). Fast Corinth V showed distinct spots with 2 ng of zeranol and 4 ng of zearalenone while faint spots were observed with estradiol and estrone standards. DES was not detectable at these levels. Less background interference was observed with Corinth V than with iodine-starch. The former confirmed spots detected by iodine-starch. This study suggests its selectivity for detection of zeranol and its metabolite, zearalanone, in the presence of steroidal compounds.

Determination of alpha- and beta-zearalenol and zearalenone in cereals by gas chromatography with ion-trap detection.

A method for determination of estrogenic mycotoxins, alpha- and beta-zearalenol and zearalenone, in cereals (wheat, barley, oats, corn) is described. After extraction with ethylacetate, clean-up involved a base treatment and partition with water; derivatization was by trimethylsilylation. For quantitation and confirmation a capillary gas chromatograph combined with a selective mass detector (ion trap), working in the electron impact-mode was used. The detection limit for the complete method is 1 microgram/kg for each of the three mycotoxins in full scan. Recoveries from spiked cereals were 82-86%.

Distribution of zeranol in bovine tissues determined by selected ion monitoring capillary gas chromatography/mass spectrometry.

Bovine tissues, including liver, muscle, kidney, bile, serum, and urine, have been quantified by selected ion monitoring capillary gas chromatography/mass spectrometry to establish the distribution of the anabolic drug, zeranol, and its metabolites, taleranol and zearalanone, after administration of zeranol to 9 bovine animals. The method used to isolate, confirm, and quantify zeranol is undergoing validation by the United States Department of Agriculture, Food Safety Inspection Service (FSIS). Application of this method demonstrates utility in determining residue levels of zeranol in a variety of tissues with levels ranging over 4 orders of magnitude (i.e., 100 parts per trillion (ppt) to 1 part per million (ppm]. The analyte levels determined in this study complement previously reported pharmacokinetic data on the distribution of zeranol in addition to providing more specific information for taleranol and zearalanone. In this quantitative study it is shown that the liver is the main organ of deposition for zeranol, taleranol, and zearalanone, that taleranol is the main metabolite in the bovine, and that zeranol is efficiently eliminated.

Determination of zeranol/zearalenone and their metabolites in edible animal tissue by liquid chromatography with electrochemical detection and confirmation by gas chromatography/mass spectrometry.

A sensitive method is described for the determination and confirmation of zeranol and zearalenone, as well as their isomers and metabolites, in edible animal tissue. The analytes are extracted from tissue with methanol, hydrolyzed enzymatically, cleaned up by acid-base partitioning, determined by liquid chromatography (LC) with electrochemical (EC) detection, and confirmed by gas chromatography/mass spectrometry (GC/MS). LC analysis is performed by isocratic elution with a buffered mobile phase using a Nova-Pak reverse-phase C18 column with amperometric EC detection at +0.90 V. Capillary GC/MS analysis of the trimethylsilyl derivatives provides mass spectral confirmations.