Determination of thyreostats in muscle and thyroid tissues by QuEChERS extraction and ultra-performance liquid chromatography tandem mass spectrometry

Hormones residues in bovine animals: Sampling, analysis and health risk assessment

The use of hormones for breeding animal livestock has been banned since 1981 under the Council Directive 81/602/EC. So far, each country should monitor the use of anabolic hormones in animal production to protect the consumer's health against these unwanted residues. This paper presents the research results on steroid and non-steroid hormones residues carried out in Lebanon from 2018 to 2020. Using a newly developed and validated LC-MS/MS method, the detection and the quantification of hormones in bovine matrices were done. The targeted matrices were muscle, liver, kidney, and bile. A total of two-hundred and forty-seven samples were collected from different slaughterhouses located in six different cities in Lebanon. Interestingly, only four hormones were found: testosterone, progesterone, epitestosterone, and 6 propyl 2thiouracil. Based on the obtained data, the estimated daily intake, hazard quotient, and hazard index were calculated to evaluate an exposure assessment.

Improved Thyreostatic Drug Detection in Animal Tissues Using Liquid Chromatography-High-Field Asymmetric Waveform Ion Mobility Spectrometry-Mass Spectrometry

Thyreostatic drugs (thyreostats) interfere with thyroid function and have been used illegally in animals slaughtered for food. Thyreostat use leads to poorer quality meat, and the drug residues can cause adverse effects in humans. These drugs, with the exception of thiouracil, do not occur naturally and require sensitive methodologies for their detection in animal tissues. Because thyreostats are low-molecular-weight polar analytes, liquid chromatography-mass spectrometry (LC-MS) is typically used for detection and, in particular, triple quadrupole mass spectrometry with selective reaction monitoring (i.e., LC-SRM). However, LC-SRM thyreostat methods suffer from chemical background noise and endogenous interferences arising from the complex tissue matrix. An improved high-field asymmetric waveform ion mobility spectrometry interface (FAIMS Pro), which separates ions based on differential ion mobility, was combined with LC-SRM to minimize these interferences. Using the same samples and conditions, LC-FAIMS-SRM showed improvements in the signal-to-noise ratio (S/N) of up to 50 times compared with our validated LC-SRM method. In addition, wider linear ranges, including substantial improvements in the lower limit of quantification (approximately an order of magnitude for tapazole and methylthiouracil), were observed with LC-FAIMS-SRM.

Mass Spectrometry-Based Determination of Thyroid Hormones and Their Metabolites in Endocrine Diagnostics and Biomedical Research – Implications for Human Serum Diagnostics

The wide spectrum of novel applications for the LC-MS/MS-based analysis of thyroid hormone metabolites (THM) in blood samples and other biological specimen highlights the perspectives of this novel technology. However, thorough development of pre-analytical sample workup and careful validation of both pre-analytics and LC-MS/MS analytics, is needed, to allow for quantitative detection of the thyronome, which spans a broad concentration range in these biological samples.

This minireview summarizes recent developments in advancing LC-MS/MS-based analytics and measurement of total concentrations of THM in blood specimen of humans, methods in part further refined in the context of previous achievements analyzing samples derived from cell-culture or tissues. Challenges and solutions to tackle efficient pre-analytic sample extraction and elimination of matrix interferences are compared. Options for automatization of pre-analytic sample-preparation and comprehensive coverage of the wide thyronome concentration range are presented. Conventional immunoassay versus LC-MS/MS-based determination of total and free THM concentrations are briefly compared.

Hollow molecularly imprinted polymer based quartz crystal microbalance sensor for rapid detection of methimazole in food samples

In this study, a novel detection method of methimazole was proposed based on the hollow molecularly imprinted quartz crystal microbalance (QCM) sensor, in which the hollow imprinted polymers (H-MIPs) were firstly prepared through the surface imprinted techniques, using hollow silica spheres as matrix supporting material and methimazole as template molecule. The characterizations of H-MIPs were carefully studied. Compared with traditional MIPs, H-MIPs exhibited faster mass transfer rate and higher adsorption capacity. After coating onto the surface of Au chip, the H-MIPs QCM sensor was fabricated. Based on the frequency shift, good linear behavior in the range of 5-70 μg L^-1, limit of detection of 3 μg L^-1, and good recoveries of 88.32%-107.96% in the spiked pork, beef and milk were obtained. The analysis process could complete within 8 min. The developed sensor provided an effective, fast and accurate method for the methimazole detection in food samples.

Fast analysis of 19 anabolic steroids in bovine tissues by high performance liquid chromatography with tandem mass spectrometry

For the detection of 19 steroid hormones in bovine muscle, a fast and sensitive liquid chromatography with electrospray ionization tandem mass spectrometry method was developed using both positive and negative ionization mode. Chromatographic separation on Poroshell 120-EC C18 column was achieved in less than 10 min using isocratic elution of mobile phase of acetonitrile/methanol/water. The compounds were extracted from muscle tissue using ethyl acetate and quick, easy, cheap, effective, rugged, and safe technique. The purification of the obtained extract was performed by dispersive solid-phase extraction with sorbents C18, primary secondary amine and magnesium sulphate. The method was validated in accordance with the Commission Decision 2002/657/EC. For all steroids tested good recoveries were obtained (from 51.2 to 121.4%) in the concentration range from decision limits until 5 µg/kg. The values of decision limits and the detection capabilities for individual compounds were in the range 0.10-0.48 and 0.17-0.95 µg/kg, respectively. The method was characterized by satisfactory linearity for most compounds (correlation coefficients   > 0.99) and the reproducibility was lower than 35%. The elaborated procedure has met the criteria for confirmatory methods and is currently used in the official control of hormones.

Determination of Thyreostats in Urine Using Supported Liquid Extraction and Mixed-Mode Cation-Exchange Solid-Phase Extraction: Screening and Confirmatory Methods

The application of thyreostats in livestock has been banned in the European Union since 1981, but these drugs are currently in the focus due to the natural occurrence of thiouracil (TU). Studies have been published on TU contamination in urine samples of animal and human origins without any drug administration of it. This paper presents new analytical methods to analyze thyreostats to support the legislation on the recommended concentration (RC) levels of these drugs. Both screening and confirmatory methods are developed for analyzing thyreostats in porcine and bovine urines using a liquid chromatography-tandem mass spectrometry technique. The new methods include a chemical derivatization with 3-iodobenzyl bromide, followed by novel purification approaches using supported liquid extraction and mixed-mode cation-exchange solid-phase extraction (SPE) for screening and confirmatory purposes, respectively. The optimized derivatization in combination with the cation-exchange SPE gives high sensitivity and reducing matrix effect of the analysis. The methods are validated in accordance with the guidelines for the validation of screening methods and European Commission Decision 2002/657/EC. The confirmatory method is used in the national monitoring plan. The detected levels of TU in urine samples are below the currently applicable RC level (10 μg L-1).

Subcritical water extraction of thyreostats from bovine muscle followed by liquid chromatography-tandem mass spectrometry

Thyreostats can be used fraudulently to promote a rapid increase in weight of breeding animals at low cost. Their severe toxicological effects impose the development of reliable analytical methods to be used in monitoring plans. This work describes an alternative approach to isolate residues of thiouracil, methyl-thiouracil, propyl-thiouracil, phenyl-thiouracil, tapazole and mercaptobenzimidazole from bovine muscle tissue. The developed procedure is based on the following three steps: i) matrix solid-phase dispersion with C₁₈ for the preliminary sample preparation; ii) subcritical water extraction (SWE) at 160°C and 100 bar; iii) clean-up on an Oasis HLB cartridge. The quantitative determination was performed by LC-MS/MS in dual polarity ionization by using internal standardization. The SWE-LC-MS/MS method was validated according to the identification criteria of the Commission decision 2002/657/EC. The relative recoveries ranged from 72 to 97%; within-lab reproducibility was less than 18%. The decision limit and the detection capability of all analytes were below the recommended concentration, set at 10 µg kg^-1, but the validation results demonstrated that this method could only be applied for screening of thiouracil and methyl-thiouracil. Besides the analytical advantages related to the use of water as solvent extraction, the procedure allowed significant removal of lipids, whose detrimental effects on instrumentation and MS sensitivity are well-known.

Abuse of anabolic agents in beef cattle: Could bile be a possible alternative matrix?

European Union prohibited the use of anabolic agents in food producing animals since 1988. An efficient control of abuses is guaranteed not only by highly performing analytical methods, but also by knowledge of metabolic pathways, kinetics of elimination and tissue distribution. To obtain data concerning metabolites production and accumulation in bile, two typical growth promoting treatments are carried out in cattle. In the first study, sixteen beef cattle were implanted with trenbolone acetate and estradiol. In the second one, three animals were implanted with zeranol and three were fed a diet containing zearalenone. Methods based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) were developed and validated to quantify the analytes of interest. The results evidenced that the biliary concentrations of the marker residues were always higher than those determined at the same time in urine and liver which are the matrices generally collected within the official monitoring programmes.

Urinary Concentrations of Steroids in Bulls under Anabolic Treatment by Revalor-XS® Implant

Despite the European ban of using anabolics in food-producing animals, growth promoters might still be illegally used in the European Union. To control the food chain and guarantee consumers' health, there is a need of highly sensitive analytical methods for the identification of marker residues of such treatments. In the present study, a group of bulls (n = 16) received trenbolone acetate (200 mg) and estradiol (40 mg) by a commercial ear implant during a time range of 71 days, and a second group (n = 16) was kept for control. The aim of the research was to measure the residual urinary concentrations of the administered drugs (β-trenbolone and β-estradiol), their main metabolites (α-trenbolone and α-estradiol), and possible alterations of the urinary profile of other endogenous hormones metabolically related. The analytical method was based on liquid chromatography-tandem mass spectrometry. Results showed average urinary concentrations of α-trenbolone and α-estradiol during treatment in the range of (0.81 ÷ 2.1) ng mL^-1 and (0.96 ÷ 4.4) ng mL^-1, respectively, whereas β-trenbolone and β-estradiol exhibit urinary concentrations lower than 0.22 ng mL^-1 in both cases. Data obtained from the urinary profiles of endogenous steroids indicate that they could be useful to indirectly detect the ongoing treatment.