Determination of zeranol, taleranol, zearalanone, α-zearalenol, β-zearalenol and zearalenone in urine by LC-MS/MS

Endocrine-disrupting compounds and metabolomic reprogramming in breast cancer

Endocrine-disrupting chemicals pose a growing threat to human health through their increasing presence in the environment and their potential interactions with the mammalian endocrine systems. Due to their structural similarity to hormones like estrogen, these chemicals can interfere with endocrine signaling, leading to many deleterious effects. Exposure to estrogenic endocrine-disrupting compounds (EDC) is a suggested risk factor for the development of breast cancer, one of the most frequently diagnosed cancers in women. However, the mechanisms through which EDCs contribute to breast cancer development remain elusive. To rapidly proliferate, cancer cells undertake distinct metabolic programs to utilize existing nutrients in the tumor microenvironment and synthesize macromolecules de novo. EDCs are known to dysregulate cell signaling pathways related to cellular metabolism, which may be an important mechanism through which they exert their cancer-promoting effects. These altered pathways can be studied via metabolomic analysis, a new advancement in -omics technologies that can interrogate molecular pathways that favor cancer development and progression. This review will summarize recent discoveries regarding EDCs and the metabolic reprogramming that they may induce to facilitate the development of breast cancer.

A comparison of four liquid chromatography-mass spectrometry platforms for the analysis of zeranols in urine

Targeted biomonitoring studies quantifying the concentration of zeranols in biological matrices have focused on liquid chromatography interfaced to mass spectrometry (LC-MS). The MS platform for measurement, quadrupole, time-of-flight (ToF), ion trap, etc., is often chosen based on either sensitivity or selectivity. An instrument performance comparison of the benefits and limitations using matrix-matched standards containing 6 zeranols on 4 MS instruments, 2 low-resolution (linear ion traps), and 2 high-resolution (Orbitrap and ToF) was undertaken to identify the best measurement platform for multiple biomonitoring projects characterizing the endocrine disruptive properties of zeranols. Analytical figures of merit were calculated for each analyte to compare instrument performance across platforms. The calibration curves had correlation coefficients r = 0.989 ± 0.012 for all analytes and LODs and LOQs were ranked for sensitivity: Orbitrap > LTQ > LTQXL > G1 (V mode) > G1 (W mode). The Orbitrap had the smallest measured variation (lowest %CV), while the G1 had the highest. Instrumental selectivity was calculated using full width at half maximum (FWHM) and as expected, the low-resolution instruments had the broadest spectrometric peaks, concealing coeluting peaks under the same mass window as the analyte. Multiple peaks from concomitant ions, unresolved at low resolution (within a unit mass window), were present but did not match the exact mass predicted for the analyte. For example, the high-resolution platforms were able to differentiate between a concomitant peak at 319.1915 from the analyte at 319.1551, included in low-resolution quantitative analyses demonstrating the need to consider coeluting interfering ions in biomonitoring studies. Finally, a validated method using the Orbitrap was applied to human urine samples from a pilot cohort study.

Preparation of highly sensitive monoclonal antibody against α-zearalanol based on the similar antigen determinant structure to zearalanone

In this study, we report a new method to prepare highly sensitive monoclonal antibody against α-zearalanol (ZAL) based on a similar antigen determinant structure. Zearalanone (ZAN), structural analogs of ZAL, was modified by oximation to obtain ZAN-O. ZAN-O was then coupled with bovine serum albumin using 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide (EDC) to synthesise the artificial complete antigen ZAN-O-BSA. ZAN-O-BSA was used to immunise the BALB/c mice. The splenocytes of the immunised mice were fused with myeloma NS0 cells. During the process of cell fusion, ZAL was used as an inhibitor instead of ZAN to screen the hybridoma cell lines that can secrete monoclonal antibodies against ZAL. The sensitivity (half inhibitory concentration, IC50) of the prepared monoclonal antibody was 0.475 ng/ml, the limit of detection (LOD) was 0.050 ng/ml, the linear range of detection was 0.066-3.399 ng/ml, the affinity constant Kaff was 6.18×107 l/mol, the cross-reactivity rate with structural analogues, such as β-zearalanol, α-zearalenol, β-zearalenol, ZAN and zearalenone were 28.07, 13.16, 15.83, 60.28 and 7.95% respectively. The cross-reactivity with other mycotoxin and carrier proteins were all less than 0.05%. The prepared monoclonal antibody can be used to establish a highly sensitive immunoassay for the detection of ZAL.

A Quantitative and Confirmatory Method Employing Liquid Chromatography Coupled to Hybrid High-Resolution Mass Spectrometry and QuEChERS for the Determination of Thirty-Seven Growth Promoter Residues in Bovine Urine

In this work, 37 growth promoters were quantitatively determined in bovine urine using a QuEChERS approach with acetonitrile, NaCl, and MgSO₄:PSA for sample extraction. The analytes were separated and detected by liquid chromatography coupled to hybrid high-resolution mass spectrometry. The method was validated in accordance with the Decision 657/2002/EC guidelines, in which recoveries fell within the range 84-113%, relative standard varied between 2 and 32%, and detection limit between 0.1 and 2.5 μg L^-1. An adequate performance was evidenced during a proficiency test evaluation, and the developed method has been applied to routine analysis of growth promoters in Brazil. A highlight is the easiness of sample extraction combined with a quantitative determination of forbidden drugs using high-resolution mass spectrometry, which enables retrospective analysis in a surveillance perspective.

Towards A New Approach for the Description of Cyclo⁻2,4-Dihydroxybenzoate, A Substance Which Effectively Mimics Zearalenone in Imprinted Polymers Designed for Analyzing Selected Mycotoxins in Urine

A method of purifying cyclododecyl 2,4-dihydroxybenzoate as a potential replacement template molecule for preparation of molecularly-imprinted polymers for isolation of zearalenone in urine was developed. Full physicochemical characteristics of cyclododecyl 2,4-dihydroxybenzoate for the first time included crystallographic analysis and molecular modelling, which made possible the determination of the similarity between the cyclododecyl 2,4-dihydroxybenzoate and zearalenone molecules. The obtained molecularly-imprinted polymers show very high in vitro selectivity towards zearalenone due to specific interactions (e.g., hydrogen bonding, molecular recognition interaction). The achieved extraction recovery exceeds 94% at the tested concentration levels (20–500 ng·mL⁻¹) with a relative standard deviation below 2%. Immunosorbents were found to have lower recoveries (below 92.5%) and RSD value between 2 and 4% for higher concentrations of the studied substance (400 ng·mL⁻¹).

Determination of Trace Zearalenone and Its Metabolites in Human Serum by a High-Throughput UPLC-MS/MS Analysis

This paper described an improved method for high-throughput and sensitive determination of zearalenone and its five metabolites (zearalanone, α-zearalenol, β-zearalenol, α-zearalanol and β-zearalanol) in human serum. Serum samples were measured both before and after enzyme hydrolysis to assess the free and total amount of each compound by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) in multi reaction monitoring (MRM) mode following off-line 96-well μElution solid-phase extraction (SPE). All the analytes were completely separated on a C18 column within 6 min. It enabled multi-sample preparation at the same time eliminating tedious evaporation and reconstitution steps, allowing 96 (one plate) samples to be processed and analyzed within 24 h. Using an isotope labelled internal standard (13C-ZEN), high recoveries were achieved for all the compounds in the range 91.6%–119.5%, with intra-day and inter-day relative standard deviations (RSDs) of less than 8%. The limits of detection (LOD) and the limits of quantification (LOQ) were 0.02–0.06 ng mL−1 (0.6–2 fmol) and 0.1–0.2 ng mL−1 (3–6 fmol), respectively, demonstrating a notable enhancement in sensitivity compared to the existing methods. The validated method was applied to the analysis of paired urine and serum samples collected from 125 healthy individuals in Henan Province, locating in the middle area of China. ZEN metabolites in human serum were significantly lower than those in urine. Only one serum sample was positive for ZEN after enzyme digestion, whereas at least one of ZEN biomarkers was detected in 75.2% of the paired urine samples. Some comparison and discussion were also included in this paper.

Multiresidue Determination of the Anabolic-Agent Residues Steroids, Stilbenes, and Resorcylic Acid Lactones in Bovine Urine by GC-MS/MS with Microwave-Assisted Derivatization

In this work, a GC-MS/MS method was developed for the determination of anabolic-agent residues in bovine urine. The optimized sample preparation was as follows: enzymatic hydrolysis by β-glucuronidase-sulfatase enzyme from Helix pomatia for 16 h at 37.5 °C, liquid-liquid extraction with diethyl ether, solid-phase extraction with HLB and aminopropylsilane cartridges, and microwave-assisted derivatization using 25 μL of MSTFA/NH₄I/ethanethiol and full microwave power for 2 min. The method was validated according to Decision 657/2002/EC, Codex Alimentarius, and Manual da Garantia da Qualidade Analítica guidelines. The acceptability criteria for quantitative analysis were met for α-ethinylestradiol, α-nandrolone, β-estradiol, β-zearalanol, β-zearalenol, drostanolone, ethisterone, dienestrol, diethylstilbestrol, hexestrol, megestrol, methyltestosterone, and zearalenone. The analytes α-zearalenol, α-zearalanol, and norethandrolone were validated for qualitative analysis.

High-throughput and sensitive determination of urinary zearalenone and metabolites by UPLC-MS/MS and its application to a human exposure study

Biomarker-based strategies to assess human exposure to mycotoxins have gained increased acceptance in recent years. In this study, an improved method based on UPLC-MS/MS following 96-well μElution solid-phase extraction was developed and validated for the sensitive and high-throughput determination of zearalenone (ZEN) and its five metabolites α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), and zearalanone (ZAN) in human urine samples, using ¹³C-ZEN as an internal standard for accurate quantification. Two plates of samples (n = 192) could be processed within 2 h, and baseline separation of all the analytes was achieved in a total runtime of 6 min. The proposed method allowed ZEN and its metabolites to be sensitively determined in a high-throughput way for the first time, and with significantly improved efficiency and accuracy with respect to existing methods. The limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.02 to 0.06 ng mL^-1 and from 0.05 to 0.2 ng mL^-1, respectively. The recoveries for the spiked samples were from 87.9 to 100%, with relative standard deviations (RSDs) of less than 7%. 301 urine samples collected from healthy volunteers aged 0-84 years in China were analyzed with and without enzyme hydrolysis to determine total and free ZEN biomarkers, respectively. ZEN, ZAN, α-ZEL, and β-ZEL were detected in 71.4% of the samples at levels of 0.02-3.7 ng mL^-1 after enzyme hydrolysis. The estimated mean probable daily intake (PDI) was much lower than the tolerable daily intake (TDI). Adolescents had higher exposure than children, adults, and the elderly. Graphical abstract ᅟ.

Comparison of the Multiple Reaction Monitoring and Enhanced Product Ion Scan Modes for Confirmation of Stilbenes in Bovine Urine Samples Using LC-MS/MS QTRAP® System

In accordance with Commission Decision 2002/657/EC, confirmatory methods for the detection of prohibited substances should comply with specific requirements, including the criteria for confirmation. Two strategies: multiple reaction monitoring (MRM) and enhanced product ion (EPI) scanning functions were compared for confirming the anabolic compounds from synthetic stilbenes group in bovine urine samples. In the research, twenty samples fortified at the Recommended Concentration (RC) of 1 µg L⁻¹ with diethylstilbestrol, dienestrol and hexestrol were analyzed by liquid chromatography-tandem mass spectrometry on a QTRAP 5500 instrument. The analytical procedure, validated in accordance with the Commission Decision 2002/657/EC, used in the official control of hormones in Poland was applied. The validation parameters were in agreement with 2002/657/EC performance criteria. The effectiveness of MRM and EPI scanning modes for confirmation purposes was evaluated based on the percentage of the results confirmed. In all urine samples recorded in the MRM mode, the confirmation criteria (retention time, relative intensities between transitions) have been fulfilled. The presence of stilbenes in all urine samples using EPI scan mode was confirmed too as evidenced by a good matching of stilbenes spectra in the samples to the reference spectra with critical match factor above 0.7. The results of the research show that EPI scanning function provides the same effectiveness for confirmation of banned compounds as the mostly used MRM scan mode and can be an additional tool to confirm the doubtful case results in the analysis of hormones residues, even at such low concentration levels.

Simultaneous determination of resorcylic acid lactones, β and α trenbolone and stilbenes in bovine urine by UHPLC/MS/MS

Treatment of cattle with α-zearalanol (zeranol, α-ZAL), a resorcylic acid lactone (RAL), is illegal in European Union countries. Zearalenone, a common contaminant of cattle feed, is also a RAL and there is evidence that it, or its metabolites, can be converted in vivo to α-ZAL (or to β-zearalanol, β-ZAL). To determine whether an animal has been treated with α-ZAL it is necessary to quantify separately all the RALs. This work presents the simultaneous determination in urine of RALs, β-trenbolone (β-TB) and its metabolite α-trenbolone (α-TB) and the stilbenes diethylstilbestrol (DES), dienestrol (DEN) and hexestrol (HEX) using Ultra High Performance Liquid Chromatography/Mass Spectrometry (UHPLC/MS/MS). Several chromatographic UHPLC columns were tested in order to achieve chromatographic separation of the analytes and the results are shown. Baseline separation of all compounds was not possible, so that careful consideration of the MRM transitions was necessary. The separation chosen for the validation work used a 100mm×2.1mm×1.7μm Phenyl column eluting with a gradient of acetonitrile/methanol/water. The method validation according to EU Decision 657/2002 included linearity, within laboratory reproducibility and trueness, decision limit (CC_α) and detection capability (CC_β). For all compounds the method was linear in the range 2-12μg/l (1 and 6μg/l for DES) with determination coefficients greater than 0.97 and linear residuals below 20%. Within laboratory reproducibility was lower than 25% and trueness less than 11% for all compounds and concentration levels. CC_α ranged from 0.6μg/l (DES) to 1.6 (α-TB) and CC_β was 0.8μg/l (α-zearalenol) to 1.9μg/l (α-TB).

Determination of chloramphenicol and zeranols in pig muscle by immunoaffinity column clean-up and LC-MS/MS analysis

An immunoaffinity column clean-up and LC-MS/MS method was successfully developed for simultaneous determination of chloramphenicol, zearalanone, α-zearalanol, β-zearalanol, zearalenone, α-zearalenol and β-zearalenol in pig muscle. The sample was extracted with diethyl ether after enzymatic digestion by β-glucuronidase/sulfatase. The extracted solution was evaporated to dryness and the residue was then dissolved in 1 ml of 50% acetonitrile solution. After filtration and dilution with phosphate buffer solution (PBS), the reconstituted solution was cleaned-up with an IAC-CZ immunoaffinity column and then analysed by HPLC-MS/MS. The established method were validated by linearity (r ≥ 0.9990), precision (RSD ≥ 2.9%), average recovery (74.5-105.0%) and limit of detection (0.04-0.10 μg kg(-1)). The developed method is rapid, reliable, sensitive, accurate and has good applicability for real samples.

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

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

Developments in mycotoxin analysis: an update for 2012-2013

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2012 and mid-2013. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxins, patulin, trichothecenes and zearalenone. A wide range of analytical methods for mycotoxin determination in food and feed were developed last year, in particular immunochemical methods and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)-based methods. After a section on sampling and sample preparation, due to the rapid spread and developments in the field of LC-MS/MS multimycotoxin methods, a separate section has been devoted to this area of research. It is followed by a section on mycotoxins in botanicals and spices, before continuing with the format of previous reviews in this series with dedicated sections on method developments for the individual mycotoxins.