Chromatographic analysis of natural and synthetic estrogens in milk and dairy products

Qualitative and Quantitative Detection of Typical Reproductive Hormones in Dairy Cows Based on Terahertz Spectroscopy and Metamaterial Technology

Progesterone (PROG) and estrone (E1) are typical reproductive hormones in dairy cows. Assessing the levels of these hormones in vivo can aid in estrus identification. In the present work, the feasibility of the qualitative and quantitative detection of PROG and E1 using terahertz time-domain spectroscopy (THz-TDS) and metamaterial technology was preliminarily investigated. First, the time domain spectra, frequency domain spectra, and absorption coefficients of PROG and E1 samples were collected and analyzed. A vibration analysis was conducted using density functional theory (DFT). Subsequently, a double-ring (DR) metamaterial structure was designed and simulated using the frequency domain solution algorithm in CST Studio Suite (CST) software. This aimed to ensure that the double resonance peaks of DR were similar to the absorption peaks of PROG and E1. Finally, the response of DR to different concentrations of PROG/E1 was analyzed and quantitatively modeled. The results show that a qualitative analysis can be conducted by comparing the corresponding DR resonance peak changes in PROG and E1 samples at various concentrations. The best R2 for the PROG quantitative model was 0.9872, while for E1, it was 0.9828. This indicates that terahertz spectral-metamaterial technology for the qualitative and quantitative detection of the typical reproductive hormones PROG and E1 in dairy cows is feasible and worthy of in-depth exploration. This study provides a reference for the identification of dairy cow estrus.

Simultaneous Determination of Steroids and NSAIDs, Using DLLME-SFO Extraction and HPLC Analysis, in Milk and Eggs Collected from Rural Roma Communities in Transylvania, Romania

This research aims to determine five steroids and four non-steroidal anti-inflammatory drugs in milk and egg samples collected from rural Roma communities in Transylvania, Romania. Target compounds were extracted from selected matrices by protein precipitation, followed by extract purification by dispersive liquid-liquid microextraction based on solidification of floating organic droplets. The extraction procedure was optimized using a 24 full factorial experimental design. Good enrichment factors (87.64-122.07 milk; 26.97-38.72 eggs), extraction recovery (74.49-103.76% milk; 75.64-108.60% eggs), and clean-up of the sample were obtained. The method detection limits were 0.74-1.77 µg/L for milk and 2.39-6.02 µg/kg for eggs, while the method quantification limits were 2.29-5.46 µg/L for milk and 7.38-18.65 µg/kg for eggs. The steroid concentration in milk samples was Collapse

Key Words

• dispersive liquid–liquid microextraction based on solidification of floating organic droplets (DLLME-SFO)
• eggs
• milk
• non-steroidal anti-inflammatory drugs (NSAIDs)
• rural Roma communities
• steroids

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MESH Headings

• Humans
• Animals
• Anti-Inflammatory Agents, Non-Steroidal
• Ketoprofen
• Naproxen
• Ibuprofen
• Milk
• Romania
• Chromatography, High Pressure Liquid
• Roma
• Estrone

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Grants

• Project contract no. 23 / 2020 EEA and Norway Grants

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Affiliation(s)

Mihaela Cătălina Herghelegiu Faculty of Environmental Science and Engineering, Babeș-Bolyai University, 1 Kogălniceanu Str., 400084 Cluj-Napoca, Romania
Vlad Alexandru Pănescu Faculty of Environmental Science and Engineering, Babeș-Bolyai University, 1 Kogălniceanu Str., 400084 Cluj-Napoca, Romania
Victor Bocoș-Bințințan Faculty of Environmental Science and Engineering, Babeș-Bolyai University, 1 Kogălniceanu Str., 400084 Cluj-Napoca, Romania
Radu-Tudor Coman Faculty of Medicine, “Iuliu Hațieganu” University of Medicine and Pharmacy, 8 Babeș Str., 400012 Cluj-Napoca, Romania
Vidar Berg Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås-Oslo, Norway
Jan Ludvig Lyche Faculty of Veterinary Medicine, Norwegian University of Life Sciences, 1433 Ås-Oslo, Norway
Maria Concetta Bruzzoniti Department of Chemistry, University of Turin, Via P. Giuria 5, 10125 Turin, Italy;
Mihail Simion Beldean-Galea Faculty of Environmental Science and Engineering, Babeș-Bolyai University, 1 Kogălniceanu Str., 400084 Cluj-Napoca, Romania

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Novel fluorescence approach for trace quantification of levonorgestrel in breast milk based on click reaction with benzonitrofurazan azide (NBD-AZ)

Although the great importance of oral contraceptive agents in birth control, their existence in breast milk became a cause for concern, since infant exposure to these hormones is associated with many health problems. Consequentially, developing a sensitive bioanalytical method for monitoring their concentrations in breast milk is an urgent demand to examine the safety or the risk of these compounds on infants. Levonorgestrel is one of the most common contraceptive hormones under concern. Despite the high sensitivity of the fluorometric methods, detection of Levonorgestrel by them is confined because its structure does not exhibit any fluorescence. For the first time, we proposed a promising click fluorescent probe, 4-azido-7-nitrobenzoxadiazole to react with the alkyne group of Levonorgestrel, to give a highly fluorescent triazole derivative that exhibited strong signal at wavelength of 544 nm after excitation at 470 nm. Reaction parameters impacting the fluorescence were cautiously studied and optimized. The suggested approach has been successfully applied in Levonorgestrel estimation in breast milk samples with linearity of (0.4-80 ng.ml-1) and low detection limit of 0.12 ng.ml-1without interferences from any biological components and with mean % recovery of 97.84 ± 2.73. Accuracy, sensitivity, selectivity, simplicity, and low-cost makes this approach a convincing, promising, and appealing alternative over reported analytical methods for Levonorgestrel bioanalysis in different matrices.

Simultaneous determination of twelve natural estrogens in dairy milk using liquid-liquid extraction and solid-phase extraction coupled with gas chromatography-mass spectrometry

There have been many analytical methods for natural estrogens in commercial dairy milk samples, but in most of which, only four major estrogens (estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-estradiol (αE2)) were included. This work developed an effective GC-MS analytical method for simultaneous analysis of twelve natural estrogens in commercial dairy milk sample, in which eight far-less well-known natural estrogens (2-hydroxyestone (2OHE1), 4-hydroxyestrone (4OHE1), 2-hydroxyestradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 16-epiestriol (16epiE3), 16α-hydroxyestrone (16αOHE1), 16-ketoestradiol (16ketoE2) and 17epiestriol (17epiE3)) were included besides the four major natural estrogens. With liquid-liquid extraction and solid phase extraction, twelve natural estrogens in commercial dairy milk could be effectively extracted. The established method showed good linearity (R2 > 0.9991), low limits of detections (LODs, 0.02-0.11 ng/g), as well as excellent recoveries (64-117%) with satisfactory low relative standard deviations (RSDs, 0.8-14.7%). This established method was applied to seven commercial dairy milk samples, and all the twelve natural estrogens were frequently detected except for 4OHE2 without detection in any sample. Our results showed that the concentration contribution ratios of the eight far-less well-known natural estrogens in commercial dairy milk samples contributed to 32-83%, while the corresponding contribution ratios based on estrogen equivalence (EEQ) were 21-62%. This work highlighted the high abundance of the eight far-less well-known natural estrogens in commercial dairy milk based on both concentration and EEQ, which has been neglected for a long time.

Twelve natural estrogens and ten bisphenol analogues in eight drinking water treatment plants: Analytical method, their occurrence and risk evaluation

Bisphenol analogues (BPs) and natural estrogens (NEs) as two important groups of endocrine-disrupting compounds (EDCs) in drinking water treatment plants (DWTPs) have been hardly investigated except bisphenol A (BPA) and three major NEs including estrone (E1), 17β-estradiol (E2) and estriol (E3). In this study, a GC-MS analytical method was firstly established and validated for trace simultaneous determination of ten BPs and twelve NEs in drinking water, which included BPA, bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), bsiphenol F (BPF), bsiphenol P (BPP), bisphenol S (BPS), bisphenol Z (BPZ), bisphenol AF (BPAF), bisphenol AP (BPAP), E1, E2, E3, 17α-estradiol (17α-E2), 2-hydroestrone (2OHE1), 16hydroxyestrone (16α-OHE1), 4-hydroestrone (4OHE1), 2-hydroxyesstradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 17-epiestriol (17epiE3), 16-epiestriol (16epiE3) and 16keto-estraiol (16ketoE2). This investigation showed that eighteen out of twenty-two targeted compounds were detected in drinking source waters of eight DWTPs with concentrations ranging from not detected to 142.8 ng/L. Although the conventional treatment process of DWTP could efficiently remove both BPs and NEs with respective removal efficiencies of 74.1%-90.9% and 74.5%-100%, BPA, BPS, BPE, BPZ, E1, 2OHE1, and 2OHE2 were found in the finished drinking waters. Chlorination could remove part of BPs and NEs, but the efficiency varied greatly with DWTP and the reason was unknown. In the finished drinking waters of eight DWTPs, the highest chemically calculated estrogen equivalence (EEQ) derived from BPs and NEs was up to 6.11 ngE2/L, which was over 22 times that could do harm to zebrafish, indicating a potential risk to human health. Given the fact that many chlorination products of BPs and NEs likely have higher estrogenic activities, the estrogenic effect of BPs and NEs in finished drinking water should be accurately examined urgently with the inclusion of BPs, NEs as well as their main chlorinated by-products. This study shed new light on the occurrence, removal, and potential estrogenic effects of BPs and NEs in DWTPs.

Ten bisphenol analogues in Chinese fresh dairy milk: high contribution ratios of conjugated form, importance of enzyme hydrolysis and risk evaluation

This study investigated concentration levels of ten bisphenols (BPs) in 13 Chinese commercial fresh low temperature dairy milk samples (fresh milk) of main local and national brands with or without enzyme hydrolysis. The results showed that at least two BPs were detected in each fresh milk sample without enzyme hydrolysis and the respective mean concentrations of bisphenol AF (BPAF), bisphenol B (BPB), bisphenol C (BPC), bisphenol F (BPF), bisphenol A (BPA), bisphenol S (BPS), bisphenol AP (BPAP), bisphenol PP (BPP), bisphenol Z (BPZ), and bisphenol E (BPE) were 0.73, 0.61, 1.86, 0.87, 0.42, 0.11, 1.06, 1.42, 1.5, and 0.04 ng/mL, while their respective detection frequencies ranged from 23.1-92.3%. These results indicated the frequent detection of BPs in fresh milk samples. With enzyme hydrolysis, the respective mean concentrations of BPAF, BPA, BPB, BPC, BPF, BPS, and BPAP were increased 7.1-107.1%, indicating the long-ignored importance of enzyme hydrolysis. The respective average estimated daily intakes (EDIs) of BPA by adult and children in China via fresh milk were 32.5 and 37.5 ng/kg bw/d, indicating that BPA in fresh milk was a crucial source to human. Six out of nine other BPs had higher average EDIs than that of BPA, among which the EDI of BPAP was almost three times that of BPA, suggesting the widespread contamination of other BPs in Chinese fresh milk.

Study of the Sensing Kinetics of G Protein-Coupled Estrogen Receptor Sensors for Common Estrogens and Estrogen Analogs

Endogenous and exogenous estrogens are widely present in food and food packaging, and high levels of natural estrogens and the misuse or illegal use of synthetic estrogens can lead to endocrine disorders and even cancer in humans. Therefore, it is consequently important to accurately evaluate the presence of food-functional ingredients or toxins with estrogen-like effects. In this study, an electrochemical sensor based on G protein-coupled estrogen receptors (GPERs) was fabricated by self-assembly, modified by double-layered gold nanoparticles, and used to measure the sensing kinetics for five GPER ligands. The interconnected allosteric constants (K_a) of the sensor for 17β-estradiol, resveratrol, G-1, G-15, and bisphenol A were 8.90 × 10^-17, 8.35 × 10^-16, 8.00 × 10^-15, 5.01 × 10^-15, and 6.65 × 10^-16 mol/L, respectively. The sensitivity of the sensor for the five ligands followed the order of 17β-estradiol > bisphenol A > resveratrol > G-15 > G-1. The receptor sensor also demonstrated higher sensor sensitivity for natural estrogens than exogenous estrogens. The results of molecular simulation docking showed that the residues Arg, Glu, His, and Asn of GPER mainly formed hydrogen bonds with -OH, C-O-C, or -NH-. In this study, simulating the intracellular receptor signaling cascade with an electrochemical signal amplification system enabled us to directly measure GPER-ligand interactions and explore the kinetics after the self-assembly of GPERs on a biosensor. This study also provides a novel platform for the accurate functional evaluation of food-functional components and toxins.

Analytical procedures for determination of phenolics active herbal ingredients in fortified functional foods: an overview

Fortification of foods with phenolic compounds is becoming increasingly popular due to their beneficial physiological effects. The biological activities reported include antioxidant, anticancer, antidiabetic, anti-inflammatory, or neuroprotective effects. However, the analysis of polyphenols in functional food matrices is a difficult task because of the complexity of the matrix. The main challenge is that polyphenols can interact with other food components, such as carbohydrates, proteins, or lipids. The chemical reactions that occur during the baking technologies in the bakery and biscuit industry may also affect the results of measurements. The analysis of polyphenols found in fortified foods can be done by several techniques, such as liquid chromatography (HPLC and UPLC), gas chromatography (GC), or spectrophotometry (TPC, DPPH, FRAP assay etc.). This paper aims to review the available information on analytical methods to fortified foodstuffs while as presenting the advantages and limitations of each technique.

Fabric Phase Sorptive Extraction of Selected Steroid Hormone Residues in Commercial Raw Milk Followed by Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry

Hormones in edible matrices, such as milk, are a subject of concern because of their adverse effects on the endocrine system and cell signaling and the consequent disruption of homeostasis in human consumers. Therefore, the assessment of the presence of hormones in milk as potential endocrine-disrupting compounds is warranted. However, the complexity of milk as a sample matrix and the ultra-low concentration of hormones pose significant analytical challenges. Fabric phase sorptive extraction (FPSE) has emerged as a powerful analytical technique for the extraction of emerging pollutants from complex aqueous matrices. FPSE allows for substantially simplified sample handling and short extraction and desorption times, as well as the decreased use of organic solvents. It is considered a green alternative to traditional extraction methodologies. In this work, the FPSE technique was evaluated to perform the simultaneous extraction of 15 steroid hormones from raw milk without employing any sample pretreatment steps. Clean and preconcentrated hormone solutions obtained from FPSE of raw milk were analyzed using ultra-high-performance liquid chromatography–tandem mass spectrometry to achieve low detection limits, which ranged from 0.047 to 1.242 ng·mL⁻¹. Because of the presence of many interferents in milk, such as proteins, lipids, and sugar, the effect of fat content on the extraction procedure was also thoroughly studied. Additionally, for the first time, the effect of lactose on the extraction of steroid hormones was evaluated, and the results showed that the extraction efficiencies were enhanced in lactose-free samples. Finally, the optimized methodology was applied to commercial samples of cow and goat milk, and no measurable concentrations of the studied hormones were detected in these samples.

Fast and simple determination of estrogens in milk powders by magnetic solid-phase extraction using carbon nitride composites prior to HPLC

A graphitic carbon nitride (g-C₃N₄/Fe₃O₄)-based magnetic solid-phase extraction (MSPE) approach was established for fast and simple analysis of estrogens in milk powders. The composites were characterized by X-ray diffractometer, scanning electron microscope, and Brunauer-Emmett-Teller surface area and pore size distribution analyzer. Compared with the bulk g-C₃N₄, g-C₃N₄/Fe₃O₄ gave a narrower distribution of mesopores and provided an enhanced surface area from 77.1 to 113.7 m²/g. Polar analytes of estrogens were selected as model compounds and the extraction of four estrogens was achieved in n-hexane using 15 mg of adsorbent within only 2 min. Possible extraction mechanism of g-C₃N₄/Fe₃O₄ for these estrogens was explored in terms of the polarity of the analytes and the adsorption performance of the adsorbent. The hydrophobicity and the hydrogen-bond interaction between the estrogens and g-C₃N₄ were responsible for the efficient adsorption. Combined with HPLC, MSPE with the prepared adsorbent gave the enhancement factors of 20 to 24 and the linear ranges of 2-200 μg/kg for 17β-estradiol and 17α-ethinylestradiol, 1.5-150 μg/kg for estrone, and 3-300 μg/kg for hexestrol. The detection limits and quantification limits for the estrogens in milk powders were 0.5-0.9 μg/kg and 1.5-3.0 μg/kg, respectively. The recoveries varied from 75.1 to 97.2%, with the intra-day and inter-day precisions ≤ 14.2%. Furthermore, the enrichment of the analytes and the clean-up of fat and protein interferences were achieved simultaneously with one-step g-C₃N₄-based MSPE. The present method was convenient, fast, and sensitive, and therefore could be successfully applied for the determination of estrogens in milk powders. Graphical abstract.

Hormones and Hormonal Anabolics: Residues in Animal Source Food, Potential Public Health Impacts, and Methods of Analysis

The demand for nutritious food, especially food of animal origin, is globally increasing due to escalating population growth and a dietary shift to animal source food. In order to fulfill the requirements, producers are using veterinary drugs such as hormones and hormone-like anabolic agents. Hormones such as steroidal (estrogens, gestagens, and androgens), nonsteroidal, semisynthetic, and synthetic or designer drugs are all growth-promoting and body-partitioning agents. Hence, in food animal production practice, farm owners use these chemicals to improve body weight gain, increase feed conversion efficiency, and productivity. However, the use of these hormones and hormonal growth-promoting agents eventually ends up with the occurrence of residues in the animal-originated food. The incidence of hormone residues in such types of food and food products beyond the tolerance acts as a risk factor for the occurrence of potential public health problems. Currently, different international and national regulatory bodies have placed requirements and legislative frameworks, which enable them to implement residue monitoring test endeavors that safeguard the public and facilitate the trading activity. To make the tests on the animal-origin food matrix, there are different sample extraction techniques such as accelerated solvent extraction, supercritical fluid extraction, solid phase extraction, solid-phase microextraction, and hollow-fiber liquid-phase microextraction. After sample preparation steps, the analytes of interest can be assayed by screening and confirmatory methods of analysis. For screening, immunological tests such as ELISA and radioimmunoassay are used. Detection and determination of the specific residues will be done by chromatographic or instrumental analysis. Mainly, among high-performance liquid chromatography, liquid chromatography with mass spectrometry (LC-MS, LC-MS/MS), and gas chromatography with mass spectrometry (GC-MS and GC-MS/MS) methods, LC-MS/MS is being preferred because of easier sample preparation without a derivatization step and high detection and quantification capacity.

Ionic liquid-supported magnetite nanoparticles as electrode modifier materials for estrogens sensing

This paper reports the application of a carbon paste electrode modified with magnetite nanoparticles and the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate in the electroanalytical determination of 17β-estradiol and estriol. These estrogens are potential endocrine disruptors and thus it is relevant the development of devices for their monitoring. Transmission electron microscopy, scanning electron microscopy and zeta potential techniques were applied to characterization of the modifier materials. In cyclic voltammetry experiments, irreversible oxidation peaks were observed for 17β-estradiol and estriol at +0.320 V and +0.400 V, respectively. The anodic currents obtained were approximately three times greater than those provided by the unmodified electrode due to the presence of magnetic nanoparticles and the ionic liquid, which improved the sensitivity of modified electrode. For the analysis, the parameters of the square-wave voltammetry (scan increment, amplitude and frequency) were optimized by Box-Behnken factorial design for each estrogen. For 17β-estradiol in B-R buffer pH 12.0, the calibration plot was linear from 0.10 to 1.0 μmol L^-1, with a detection limit of 50.0 nmol L^-1. For estriol in B-R buffer pH 11.0, the linear range was 1.0 to 10.0 μmol L^-1, with a detection limit of 300.0 nmol L^-1. The modified electrode was applied in the determination of 17β-estradiol and estriol in pharmaceutical formulations and the results were comparable to those obtained using UV/VIS spectrometry. Statistical tests were applied to evaluate the results and it was concluded that there was no significant difference regarding the precision and accuracy of the data provided by the two methods.

Dissolved Black Carbon as an Efficient Sensitizer in the Photochemical Transformation of 17β-Estradiol in Aqueous Solution

Dissolved black carbon (DBC) is an important component of the dissolved organic matter (DOM) pool. Nonetheless, little is known about its role in the photochemical processes of organic contaminants. This study investigated the effect of DBC on the phototransformation of 17β-estradiol in aqueous solutions under simulated sunlight. Four well-studied dissolved humic substances (DHS) were included as comparisons. DBC acted as a very effective sensitizer to facilitate the phototransformation of 17β-estradiol. The apparent quantum yield for 17β-estradiol phototransformation mediated by DBC was approximately six times higher than that by DHS at the same carbon concentration. Quenching experiments suggested that direct reaction with triplet-excited state DBC (³DBC*) was the predominant pathway of 17β-estradiol phototransformation. The higher mediation efficiency of DBC than DHS is likely due to the higher contents of aromatic groups and smaller molecular sizes, which facilitated the generation of ³DBC*. The apparent quantum yield of triplet-excited states production for DBC was 4-8 times higher than that for DHS. The results suggest that ³DBC* may have a considerable contribution to the overall photoreactivity of triplet-excited state DOM in aquatic systems. Our findings also imply that DBC can play an important role in the phototransformation of organic contaminants in the environments.

Reproductive drugs and environmental contamination: quantum, impact assessment and control strategies

Industrial and municipal solid wastes, noise, pesticides, fertilizers and vehicular emission are visible pollutants responsible for environmental contamination and ill-effects on health of all living systems. But, environmental contamination due to drugs or medicines used for different purposes in humans and animals goes unseen largely and can affect the health of living system severely. During the last few decades, the usage of drugs has increased drastically, resulting in increased drug load in soil and water. Contraceptive and fertility drugs are extensively and effectively used in humans as well as animals for different purposes. Usage of these reproductive drugs in humans is increased manifold to manage reproductive problems and/or for birth control with changing lifestyles. These drugs are excreted in urine and faeces as metabolite or conjugated forms, leading to contamination of water, milk and animal produce, which are consumed directly by humans as well as animals. These drugs are not eliminated even by water treatment plant. Consumption of such contaminated water, milk, meat and poultry products results in reproductive disorders such as fertility loss in men and increase risk of different types of cancers in humans. Therefore, assessment of impact of environmental contamination by these drugs on living system is of paramount importance. The purpose of this review article is to provide a comprehensive analysis of various research and review reports on different contraceptive and fertility drugs used in human and animals, their occurrence in the environment and their ill-effects on living systems. The approaches to control this invisible menace have also been proposed.

Multiclass analytical method for the determination of natural/synthetic steroid hormones, phytoestrogens, and mycoestrogens in milk and yogurt

Within this study, a new method enabling monitoring of various estrogenic substances potentially occurring in milk and dairy products was proposed. Groups of compounds fairly differing in physico-chemical properties and biological activity were analyzed: four natural estrogens, four synthetic estrogens, five mycoestrogens, and nine phytoestrogens. Since they may pass into milk mainly in glucuronated and sulfated forms, an enzymatic hydrolysis was involved prior to the extraction based on the QuEChERS methodology. For the purification of the organic extract, a dispersive solid-phase extraction (d-SPE) with sorbent C18 was applied. The final analysis was performed by ultra-high-performance liquid chromatography (UHPLC) coupled with triple quadrupole tandem mass spectrometry (MS/MS). Method recovery ranged from 70 to 120% with a relative standard deviation (RSD) value lower than 20% and limits of quantification (LOQs) in the range of 0.02-0.60 μg/L (0.2-6.0 μg/kg dry weight) and 0.02-0.90 μg/kg (0.2-6.0 μg/kg dry weight) for milk and yogurt, respectively. The new procedure was applied for the investigation of estrogenic compounds in 11 milk samples and 13 yogurt samples from a Czech retail market. Mainly phytoestrogens were found in the studied samples. The most abundant compounds were equol and enterolactone representing 40-90% of all estrogens. The total content of phytoestrogens (free and bound) was in the range of 149-3870 μg/kg dry weight. This amount is approximately 20 times higher compared to non-bound estrogens.

Hollow fiber membrane-coated functionalized polymeric ionic liquid capsules for direct analysis of estrogens in milk samples

Protein removal process is always time-consuming for the analysis of milk samples. In this work, hollow fiber membrane-coated functionalized polymeric ionic liquid (HF-PIL) capsules were synthesized and used as solid-phase microextraction (SPME) sorbent for direct analysis of estrogens in milk samples. The functionalized PIL monolith sorbent was obtained by copolymerization between 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer and 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL-crosslinking agent. A group of four capsules were installed as SPME device, to determine four kinds of estrogens (estrone, diethylstilbestrol, hexestrol, and 17α-ethynylestradiol) in milk samples, coupled to high performance liquid chromatography. Extraction and desorption conditions were optimized to get satisfactory extraction efficiency. Good linearity was obtained in the range of 5-200 μg L(-1). The limits of detection were 1 μg L(-1) for diethylstilbestrol and 2 μg L(-1) for 17α-ethynylestradiol, estrone, and hexestrol. The present method was applied to analyze the model analytes in different milk samples. Relative recoveries were in the range of 85.5-112%. The HF-PIL SPME capsules showed satisfactory extraction efficiency and high resistance to sample matrix interference.

Application of the yeast-based reporter gene bioassay for the assessment of estrogenic activity in cow's milk from Poland

Milk contain compounds acting through the estrogen receptor signaling. The still open question whether such estrogens pose a risk for human health, encouraged us to measure the overall estrogenic activity of cow's milk in the in vitro yeast reporter bioassay. First, we assessed the ability of the bioassay to detect estrogens frequently detected in milk. The relative potencies of 16 compounds descended in the order: 17β-estradiol (17β-E2), 17α-ethinylestradiol, diethylstilbestrol, dienestrol, 17α-E2, estrone, zearalenone, estriol, equol, genistein, 17β-E2 glucuronide, bisphenol A, apigenin, daidzein. Flavone, 4-n-nonylphenol and 4-t-octylphenol shown no activity in the bioassay.The estrogenic activities of milk samples without hydrolysis were below the detection limit, whereas in 50% of the deconjugated samples they varied between 0.29 and 0.49 ng EEQ mL(-1). We also compared the estrogenic activity in raw cow's milk collected from rural and industrial locations in Poland. In our pilot study we did not observe statistically significant difference in estrogenic activities in milk collected from the two locations. We found that the daily intake of estrogens with milk may be higher than estrogen levels in human serum. Further studies are warranted to evaluate the significance of milk and dairy as a source of estrogens for humans.

Analysis of Naturally Occurring Steroid Hormones in Infant Formulas by HPLC-MS/MS and Contribution to Dietary Intake

Milk is a natural fluid and as such contains small amounts of naturally occurring steroids. Human milk is recommended as the optimal source of nutrients for infants and young children, and it has been associated to several short- and long-term benefits. For this reason, its composition is used as a reference for designing infant formulas. However, the available information on the hormonal levels of these dairy products is scarce, and it is usually limited to estradiol and estrone. In the present study, six natural sex hormones (pregnenolone, progesterone, estrone, dehydroepiandrosterone, testosterone and androstenedione) have been extracted from sixteen milk-based infant formulas and analyzed with liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The purpose of this research was to quantify natural steroid hormones in various infant formulas, to provide food and nutrition practitioners with information to estimate intakes in children. In addition, data found in the literature was used for comparison. The findings suggest that there are certain similarities between bovine milk and dairy products for infants. Furthermore, the detected levels were in general lower than those observed in human milk and/or colostrum. The reported results represent a valuable addition to the current knowledge on natural hormone content of infant foods.

Simultaneous Determination of Naturally Occurring Estrogens and Mycoestrogens in Milk by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry Analysis

A simple, fast, and reproducible method for the simultaneous determination of natural estrogens and mycoestrogens (resorcylic acid lactones) in milk by ultrahigh-performance liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry (UHPLC/ESI-MS/MS) is described. The extraction was carried out by solid-phase extraction (SPE) using graphitized carbon black as solid sorbent. The use of carbon black allowed us to avoid any type of sample pretreatment, and the extraction was performed simply by diluting milk samples in water. Correlation coefficient values were obtained in the range between 0.9991 and 1, with good recoveries (67-107% at the lowest spiked level), repeatability (4.8-16.8%), and reproducibility (3.2-16.3%). Moreover, a very low matrix effect was observed for both estrogens and mycoestrogens. With respect to a previous method based on SPE with Oasis MAX cartridges, the one here described allowed us to detect all the analytes under investigation, at the lowest tested concentration level, including free estrogens (in particular estriol). Finally, the developed UHPLC/ESI-MS/MS method was applied to the analysis of some whole milk samples from different lactating animals (cow, goat, and donkey) as well as ultrahigh-temperature-treated cow milk and powder milk samples.

Direct and indirect photodegradation of estriol in the presence of humic acid, nitrate and iron complexes in water solutions

The photochemical behavior of a natural estrogen estriol (E3) was investigated in the presence of the natural photoreactive constituents including nitrate, iron(III), and humic acid (HA). The direct photodegradation of E3 increased with increasing incident light intensity, decreasing initial concentration of E3 and increasing pH in the range of 6.0 to 10.0. The direct photodegradation of the deprotonated speciation of E3 was much faster than that of its protonated form. The presence of NO3(-) and iron(III) promoted the photochemical loss of E3 in the aqueous solutions. The quenching experiments verified that hydroxyl radicals were predominantly responsible for the indirect photodegradation of E3. HA could act as photosensitizer, light screening agent and free radical quencher. For the first time, the enhancement or inhibition effect of HA on photodegradation was found to depend on the irradiation light intensity. HA enhanced the photodegradation of E3 under sunlight or weak irradiation of simulated sunlight. In contrast, under high irradiation light intensity, HA inhibited the photodegradation. The hydroxylation photoproducts were identified using GC-MS and the photodegradation pathway of E3 was proposed.

Comparison of different mesoporous silicas for off-line solid phase extraction of 17β-estradiol from waters and its determination by HPLC-DAD

Functionalized (SBA-C₁₈ and SM-C₁₈) and non-functionalized (SBA-15 and SM) mesoporous silicas were then examined as sorbents for solid-phase extraction of 17β-estradiol in aqueous media. Experiments were run in order to test critical factors affecting the procedure extraction efficiency, including the type of sorbent, the analyte concentration, the solvent and volume used for elution and the sample volume. Among the prepared materials, SBA-C₁₈ had the highest adsorption affinity towards 17β-estradiol and under optimized conditions (200mg of sorbent, 150 mL of water sample, elution with 3 × 2 mL of methanol) this sorbent proved good extraction capacity and elution efficiency for this hormone from aqueous media (recovery near 100%). To evaluate the analytical applicability of the proposed method, it was applied to the determination of 17β-estradiol in drinking water by high performance liquid chromatography with a photodiode array detector. Calibration curves were shown to be linear between 1.25 and 100 mg L(-1)with correlation coefficients ≥0.999 (n=5) for 17β-estradiol. The instrumental detection and quantitation limits calculated were 0.38 and 1.25 mg L(-1), respectively. The relative standard deviation obtained values were ≤3% and the mean recoveries obtained were of 82%. The results suggest that SBA-C18 is a promising material for the off-line solid phase extraction of 17β-estradiol from waters.

Analytical strategies based on chromatography-mass spectrometry for the determination of estrogen-mimicking compounds in food

Food safety can be compromised by the presence of a wide variety of substances, deriving from both natural and anthropogenic sources. Among these substances, compounds exhibiting various degrees of estrogenic activity have been widely studied in environmental samples, whereas less attention has been devoted to food matrices. The aim of the present review is to give a general overview on the recent analytical methods based on gas or liquid chromatography coupled to mass spectrometry for the determination of estrogen-like compounds in foods, including new developments, improvements and upcoming trends in the field. Attention will be focused on four representative groups of compounds, i.e. natural and synthetic estrogens, mycoestrogens, phytoestrogens, and alkylphenols.