Identification of hormone esters in injection site in muscle tissues by LC/MS/MS

Analysis of organochlorine pesticides residues in fish from Edko Lake (North of Egypt) using eco-friendly method and their health implications for humans

Levels of organochlorine pesticides (OCPs) residues in tilapia fish and their health risk associated with the consumption of fish from Edko lake, Egypt were determined. The quick, easy, cheap, effective, rugged, and safe method (QuEChERS) was used for extraction and clean-up of 18 OCPs residues from fish followed by GC-ECD and GC-ITD analytical tools were employed for identification of OPs. Out of the 18 OCPs, only heptachlorepoxide, p,p-DDE, dieldrin, p,p-DDD, and endrin ketone were detected in muscles of fish with concentrations of 0.1144, 0.2119, 0.4352, 0.1196, and 0.1323 µg/Kg bw, respectively. Results of the risk assessment calculations showed that dieldrin had a health risk index of more than one. This means that there was a health risk to adults associated with the consumption of fish. On the other hand, heptachlorepoxide, p,p-DDE, p,p-DDD, and endrin ketone did not show any direct health risk. Contamination of fish, collected from Edko lake in Egypt, with residues of OCPs might pose health implications if fish were consumed fresh.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43188-020-00085-8.

Validation of an enzyme immunoassay for the quantification of testosterone in green iguana males (Iguana iguana)

The endocrinological study by immunological methods allows elucidating mechanisms of response to environmental challenges and reproductive regulatory mechanisms in animals. However, it is often overlooked that immunological assays for the detection and quantification of steroid hormones require prior validation tests. In this study, the efficacy of a commercial enzyme immunoassays (EIA) was evaluated for the quantification of plasma testosterone (T) in males from a population of green iguanas (Iguana iguana) in semi-captivity. The enzyme immunoassay was validated for specificity, accuracy and precision. Testosterone concentrations obtained by EIA were compared to estimates obtained on the same samples by high-performance liquid chromatography (HPLC). The proposed protocol has shown linearity and parallelism, T recovery was found to be within 80-110% accuracy, and precision variation was <10%. The EIA method allowed the differentiation of the plasma T concentration of male iguanas during the reproductive season (29.7 ± 14.4 ng mL^-1, n = 4) and outside the reproductive season (6.8 ± 2.0 ng mL^-1, n = 4). The HPLC method has been able to detect concentrations of T only for those individuals during the reproductive season. The T concentrations obtained by the two methods were not statistically different (p > 0.05) indicating that the commercial EIA kit analyzed can be employed in the laboratory routine to quantify plasma T concentration and consequently differentiate the reproductive status of green iguana males.

Determination of Steroid Esters in Hair of Slaughter Animals by Liquid Chromatography with Tandem Mass Spectrometry

Introduction

The use of growth promoters in animal husbandry to increase weight gain and efficiency of feed conversion into muscle has been banned in the European Union since 1988, and under Directive 96/23/EC, surveillance for anabolic steroid hormones is obligatory. The hormones present in animal tissues may be of endogenous origin or may result from illegal administration. Steps have been taken to determine selected steroids in the form of esters in the alternative matrix of animal hair. Their detection in biological material is direct proof of the illegal use of anabolics.

Material and Methods

The procedure for the determination of steroid esters in animal hair, based on digestion, extraction, purification, and liquid chromatography with tandem mass spectrometry was validated under the current regulations. In total, 348 samples of animal hair were examined using this method.

Results

Good recoveries and precision values (RSD) were obtained during validation. Decision limits (CCα) and detection capabilities (CCβ) were in the ranges of 2.57-4.18 μg kg^-1 and 4.38-7.12 μg kg^-1, respectively. The method met the criteria for confirmation techniques with respect to Commission Decision 2002/657/EC.

Conclusion

Testing for steroid esters in animal hair was introduced into the National Residue Control Programme in 2017. Steroid esters were not found in any hair samples above the CCα, which indicates that illegal use of anabolics was not confirmed.

Determination of four Alternaria alternata mycotoxins by QuEChERS approach coupled with liquid chromatography-tandem mass spectrometry in tomato-based and fruit-based products

A liquid chromatography-tandem mass spectrometry method for the determination of four Alternaria toxins, i.e. alternariol, alternariol monomethyl ether, tentoxin, and tenuazonic acid in tomato-based and fruit-based products was developed using a QuEChERs approach for the extraction of the mycotoxins. To optimise the QuEChERs extraction, several parameters were tested: types of QuEChERs pouches, sample weights, quantities of added water, use of dispersive SPE as a purification step, types of solvent and conditions of shaking. The method showed good linearity (R² > 0.997) and precision (RSD% < 10) for all analytes. Tenuazonic acid showed very good recovery (98.8%-108.9%) for tomato-based products, as well as for fruit-based products. The method was successfully applied to 57 samples collected from the Italian market. Tenuazonic acid was found in appreciable concentrations in some products. The highest value was found in a tomato sauce sample (814 μg/kg).

The use of gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry to demonstrate progesterone treatment in bovines

Currently, no analytical method is available to demonstrate progesterone administration in biological samples collected in rearing animals, and therefore, tracking the abuse of this popular growth promoter is arduous. In this study, a method is presented to reveal progesterone (PG) treatment on the basis of carbon isotope measurement of 5β-pregnane-3α, 20α-diol (BAA-PD), a major PG metabolite excreted in bovine urine, by gas chromatography-mass spectrometry/combustion/isotope ratio mass spectrometry (GC-MS/C/IRMS). 5-Androstene-3β,17α-diol (AEdiol) is used as endogenous reference compound. Intermediate precisions (n=11) of 0.56‰ and 0.68‰ have been determined for AEdiol and BAA-PD, respectively. The analytical method was used for the very first time to successfully differentiate urine samples collected in treated and untreated animals.

Liquid chromatography-mass spectrometry method for the quantitative determination of residues of selected veterinary hormones in powdered ingredients derived from bovine milk

A rugged, quantitative liquid chromatography-tandem mass spectrometry method with modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample preparation for 17 selected veterinary hormones in six different powdered ingredients derived from bovine milk was developed and comprehensively validated. A universal post-extraction spiked matrix-matching approach based on whole milk powder has been successfully implemented. Three validation runs based on four levels of pre-extraction spiked quality control (QC) samples have been conducted. Overall accuracy (86-117%), overall precision (<20% RSD), selectivity, absolute extraction recovery (62-82%), matrix effect (<15% for most compounds), limits of detection (0.1-0.8 μg/kg, except for diethylstilbestrol at 3.8 μg/kg), limits of quantitation (0.2-2.0 μg/kg, except for diethylstilbestrol at 10.0 μg/kg), and extract stability (48 h) have been determined. The method is proposed for the routine analysis of hormones potentially present in powdered ingredients derived from bovine milk.

Endogenous steroid profiling by gas chromatography-tandem mass spectrometry and multivariate statistics for the detection of natural hormone abuse in cattle

For years it has been suspected that natural hormones are illegally used as growth promoters in cattle in the European Union. Unfortunately there is a lack of methods and criteria that can be used to detect the abuse of natural hormones and distinguish treated from non-treated animals. Pattern recognition of steroid profiles is a promising approach for tracing/detecting the abuse of natural hormones administered to cattle. Traditionally steroids are analysed in urine as free steroid after deconjugation of the glucuronide (and sulphate) conjugates. The disadvantage of this deconjugation is that valuable information about the steroid profile in the sample is lost. In this study we develop a method to analyse steroids at very low concentration levels (ng l(-1)) for the free steroid, glucuronide and sulphate conjugates in urine samples. This method was used to determine concentrations of natural (pro)hormones in a large population (n = 620) of samples from male and female bovine animals and from bovine animals treated with testosterone-cypionate, estradiol-benzoate, dihydroepiandrosterone and pregnenolone. The data acquired were used to build a statistical model applying the multivariate technique 'Soft Independent Modeling of Class Analogy' (SIMCA). It is demonstrated that by using this model the results of the urine analysis can indicate which animal may have had illegal treatment with natural (pro)hormones.

Surveillance study of a number of synthetic and natural growth promoters in bovine muscle samples using liquid chromatography-tandem mass spectrometry

A simple, new method permitting the simultaneous determination and confirmation of trace residues of 24 different growth promoters and metabolites using liquid chromatography-mass spectrometry was developed and validated. The compounds were extracted from bovine tissue using acetonitrile; sodium sulphate was also added at this stage to aid with purification. The resulting mixture was then evaporated to approximately 1 ml and subsequently centrifuged at high speed and an aliquot injected onto the LC-MS/MS system. The calculated CCα values ranged between 0.11 and 0.46 µg kg(-1); calculated CCβ were in the range 0.19-0.79 µg kg(-1). Accuracy, measurement of uncertainty, repeatability and linearity were also determined for each analyte. The analytical method was applied to a number of bovine tissue samples imported into Ireland from third countries. Levels of progesterone were found in a number of samples at concentrations ranging between 0.28 and 30.30 µg kg(-1). Levels of alpha- and beta-testosterone were also found in a number of samples at concentrations ranging between 0.22 and 8.63 µg kg(-1) and between 0.16 and 2.08 µg kg(-1) respectively.