Residue analysis of glucocorticoids in bovine milk by liquid chromatography–tandem mass spectrometry

Simultaneous determination of 58 glucocorticoid residues in milk by ultra-high performance liquid chromatography-tandem mass spectrometry

Abuse of glucocorticoid veterinary drugs in dairy industry can potentially threat milk safety and consequently influence human health. Here a reliable method for determination of 58 glucocorticoid drug residues in milk was established by combining solid phase extraction with ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The analytes were extracted with acetonitrile and cleanup with EMR-Lipid lipid removal column. The analytes were chromatographically separated using Poroshell EC-C18 column and acquired by electrospray ionization with multiple-reaction monitoring (MRM) mode. The limit of quantification (S/N ≥ 10) ranged from 0.2 to 2.0 µg/kg and the limit of detection (S/N ≥ 3) ranged from 0.1 to 1.0 µg/kg. Average recoveries were from 71% to 113%, the relative standard deviations (RSDs) were less than 15%, and the correlation coefficients (R2) of calibration curves exceeded 0.99. The method was applied to detect twenty milk products obtained from local supermarkets including ten pasteurized milk and ten UHT milk. Two endogenous glucocorticoids, i.e. hydrocortisone and cortisone were detected but not exceed the maximum residue limits (MRLs).

Chiral Nano-Liquid Chromatography and Dispersive Liquid-Liquid Microextraction Applied to the Analysis of Antifungal Drugs in Milk

A novel chromatographic application in chiral separation by using the nano-LC technique is here reported. The chiral recognition of 12 antifungal drugs was obtained through a 75 µm I.D. fused-silica capillary, which was packed with a CSP-cellulose 3,5-dichlorophenylcarbamate (CDCPC), by means of a lab-made slurry packing procedure. The mobile phase composition and the experimental conditions were optimized in order to find the optimum chiral separation for some selected racemic mixtures of imidazole and triazole derivatives. Some important parameters, such as retention faction, enantioresolution, peak efficiency, and peak shape, were investigated as a function of the mobile phase (pH, water content, type and concentration of both the buffer and the organic modifier, and solvent dilution composition). Within one run lasting 25 min, at a flow rate of approximately 400 nL min^-1, eight couples of enantiomers were baseline-resolved and four of them were separated in less than 25 min. The method was then applied to milk samples, which were pretreated using a classical dispersive liquid-liquid microextraction technique preceded by protein precipitation. Finally, the DLLME-nano-LC-UV method was validated in a matrix following the main FDA guidelines for bioanalytical methods.

Residue analysis of a synthetic glucocorticoid in liver samples by a 1HMR spectroscopy approach: An exploratory study on animal model

Betamethasone is a glucocorticoid authorised in cattle for the treatment of metabolic and inflammatory diseases, but, in Europe, it is illegally employed to improve productive performances. LC-MS/MS is the official control method of veterinary drugs residues in food of animal origin. An experimental study was developed to evaluate the feasibility of proton magnetic resonance spectroscopy (1H-MRS) as a potential alternative approach to detect the presence of betamethasone residues. Eight rat liver samples were collected 24 h post-betamethasone-treatment from experimental and control animals and were analysed by 1H-MRS using a 7-Tesla MRI scanner. 1H-MR reference spectra both of the Bentelan formulation used for treatment, and of three solutions of betamethasone in dimethyl sulphoxide (DMSO) at 5, 10 and 100 mM, respectively, were acquired to fit analyte-peaks in the liver samples spectra. Betamethasone-peaks were found only in the 100 mM betamethasone in DMSO solution spectrum. Betamethasone residues were not detected in any of the tissue samples analysed, probably related to the low concentration of injected drug. These findings allow us to establish, for the first time in the literature, the detection limit (in the range 10-100 mM) of betamethasone for the 7-Tesla MRI scanner used here. Given this very-low sensitivity, we conclude that the evaluated 1H-MR spectroscopy approach is not suitable for the detection of betamethasone residues in edible tissues, since the maximum residue limit imposed by Commission Regulation (EC) 37/2010 for betamethasone in the liver, and metabolic concentrations required to be detected in animal samples from livestock, are far below the detection limit we found.

Determination and occurrence of natural and synthetic glucocorticoids in surface waters

Glucocorticoids (GCs) have been increasingly reported to have adverse effects on aquatic organisms, but the lack of comprehensive analytical methods for a broad number of GCs has limited the effective management of pollution by these molecules in surface and coastal waters. In this study, we developed an original analytical method for simultaneously monitoring 25 natural GCs, and 43 synthetic GCs (4 hydrocortisone types, 6 acetonide types, 8 betamethasone types, 14 halogenated esters, and 11 labile prodrug esters) in water samples. Of the river samples investigated, 15 natural and 25 synthetic compounds were detected with the concentrations ranging from 0.13 ng/L (11-epitetrahydrocortisol) to 433 ng/L (cortisone) and from 0.05 (clobetasol) to 94 ng/L (prednisolone), respectively. Thirteen natural metabolites of cortisol (CRL) were first detected, and their concentrations were up to 36 times higher than that of CRL. Hydrocortisone-type GCs were the dominant synthetic compounds (≤154 ng/L), followed by halogenated esters (≤81 ng/L), acetonide type GCs (≤57 ng/L), betamethasone type GCs (≤32 ng/L), and labile prodrug esters (≤22 ng/L). Considering the relative potencies for detected GCs compared to dexamethasone, halogenated esters predominantly contributed to the GC activities in the samples. Notably, this is the first report of the halogenated esters 11-oxo fluticasone propionate (OFP) and cloticasone propionate (CTP) in environmental waters. Untreated wastewater is the main source of GCs in the studied waters, and the concentration ratios between natural and synthetic GCs can be used as potential indicators of sewage input. Because of the high detected concentrations and bioactivity potency of halogenated GCs, they are the main contributors to GC activities in the studied waters, and deserved more study in the future.

Trace analysis of corticosteroids (CSs) in environmental waters by liquid chromatography-tandem mass spectrometry

Natural and synthetic corticosteroids (CSs) are a class of steroid hormones which could potentially disturb the corticosteroid signaling pathways in wildlife and humans. In this study, a sensitive and robust analytical method using solid phase extraction (SPE) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for simultaneous analysis of sub-ng/L concentrations of 26 CSs in highly complex natural water matrices. The method performance was validated for WWTP influent, effluent, surface water and finished drinking water. Low practical quantification levels (PQLs) were achieved as 0.008-0.16 ng/L in finished drinking water, 0.019-0.50 ng/L in surface water, 0.047-1.5 ng/L in WWTP effluent, and 0.10-3.1 ng/L in WWTP influent, respectively, with the recoveries ranging from 70% to 130%. The cleanup performance and matrix interferences were also evaluated. This method was then applied to the analysis of target CSs in WWTP influent and effluent samples collected from a local WWTP, as well as surface water downstream of the WWTP outfall, detecting an average summed CS concentration of 744 ng/L in influent, 23.4 ng/L in effluent and 10.9 ng/L in surface water. Four synthetic CSs (triamcinolone acetonide, fluocinolone acetonide, clobetasol propionate, and fluticasone propionate) were found poorly removed in the WWTP. The developed method provides a tool to obtain occurrence data of corticosteroids in environmental waters, which will permit assessing their risk to environmental organisms.

Stability of Cortisol and Cortisone in Human Breast Milk During Holder Pasteurization

Human donor milk is the feeding of choice for preterm infants, when own mother's milk is not available. Holder pasteurization is necessary to secure the safety of donor milk, although it can affect milk quality by reduction of nutritional and bioactive components. Recently, research has focused on the potential role of breast milk glucocorticoids for infant development. At this moment, it is unknown whether pasteurization affects milk glucocorticoid levels. Therefore, we assessed whether Holder pasteurization, the most frequently used method nowadays, reduces breast milk cortisol and cortisone levels, using breast milk samples from 30 women who delivered at term. We found tight correlations between pre- and postpasteurization levels of cortisol (R = 0.99) and cortisone (R = 0.98), and good agreement in Passing and Bablok regression analysis. In conclusion, cortisol and cortisone in human term breast milk are not significantly affected by Holder pasteurization.

Veterinary drugs residues: a review of the latest analytical research on sample preparation and LC-MS based methods

The world population is increasing and there is a growing demand for food, leading to intensification of farming methods and a requirement for more coadjuvants. Potential high profits sometimes lead to fraudulent use of drugs and pesticides. Veterinary drugs in particular can pose a real risk to human health if their residues are allowed to enter the food chain. Parent drugs and their metabolites can occur in foodstuffs individually or as multicomponent mixtures with enhanced adverse effects. In order to protect consumer safety, the European Union has established lists of forbidden substances, maximum residue limits for authorised drugs and precise criteria for confirmation analyses and interpretation of the results. Due to their nature and potential danger, the 'best available technique' should always be applied. Following this principle, this review examines the procedures and techniques applied to monitoring pharmaceutical products of major concern (e.g. anthelmintics, NSAIDs, corticosteroids, coccidiostats) in foods of animal origin, discussing advances over the past five years and future trends in the field of food safety. Our goal was both to focus attention on this important topic and to provide a selection of the most relevant recent papers on drug residues in foodstuffs.

Detection and characterization of triamcinolone acetonide metabolites in human urine by liquid chromatography/tandem mass spectrometry after intramuscular administration

RATIONALE

Glucocorticosteroids are prohibited in sports when used by systemic administrations (e.g. intramuscular, IM), whereas they are allowed using other ways of administration. Strategies to discriminate between administrations routes have to be developed by doping control laboratories. For this reason, the metabolism of triamcinolone acetonide (TA), one of the most used glucocorticosteroids, was studied using liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS).

METHODS

Urine samples obtained after IM administration of TA were analyzed using two sample treatments: (a) hydrolysis with β-glucuronidase enzymes and liquid-liquid extraction under alkaline conditions, and (b) liquid-liquid extraction under acidic conditions. The extracts were analyzed by LC/MS/MS.

RESULTS

TA, commercially available metabolites (6β-hydroxytriamcinolone acetonide, 6β-OH-TA, and triamcinolone), and their C20-reduced derivatives showed characteristic fragmentation behavior. Besides common product ions and neutral losses for corticosteroids containing fluorine, additional characteristic neutral losses (58 Da, loss of acetone; 44 Da, loss of acetaldehyde) were observed in positive electrospray ionization. Based on that behavior, two complementary approaches were applied to detect TA metabolites: (a) open detection by precursor ion and neutral loss scan methods and (b) targeted detection by selected reaction monitoring methods (SRM) containing theoretical ion transitions of the potential metabolites. Two main compounds, TA and 6β-OH-TA, and nine minor potential metabolites, were detected by open screening methods. Using SRM, two additional metabolites were detected. Some of the metabolites were characterized using reference standards and, for the rest of metabolites, feasible structures were proposed based on mass spectrometric data.

CONCLUSIONS

Metabolites resulting from hydroxylation in C-6, oxidation of the 11-hydroxyl group, reduction of the Δ(4) double bond and oxidation of the side chain were detected. Some of them have not been previously described. Excretion profiles of the detected metabolites after IM administration are presented.

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.

Analytical investigations about the presence of prednisolone in cow urine

Since 2008, the analyses carried out in the Lombardia region as part of National Residue Control Plans have evidenced unexpected frequent detection of the corticosteroid prednisolone (PRED) in cow urine samples taken to the slaughterhouse. Considering the scarce plausibility of these high frequent findings, analytical investigations were started to ascertain the real presence of this corticosteroid. The applied confirmatory method involved liquid-chromatography low-resolution tandem mass spectrometry (triple quadrupole) as instrumental technique, and it was validated in compliance with the requirements of the Commission Decision 2002/657/EC. However, recently some criticism regarding Commission Decision 2002/657/EC identification criteria has been pointed out, experimentally demonstrating false positive results (wrong identification) although these criteria have been strictly observed. Therefore, considering the serious implications (i.e. the possibility that PRED could be considered endogenous in particular animal conditions), studies were carried out to investigate the reliability of PRED identification through the change of the chromatographic conditions (mobile phases, gradient and analytical column) of the confirmatory procedure routinely applied. Further confirmation came from the application of high-resolution mass spectrometry technique (MS(2) and MS(3) experiments) to analyze incurred cow urines samples. All the obtained results confirmed definitively the real presence of this corticosteroid excluding false-positive findings in routine analysis. In addition, other experiments demonstrated that high-resolution mass spectrometers (Time of Flight and Orbitrap technologies) could be successfully applied to routine determination of steroid residues in biological fluids at very low concentrations (< 1 µg L(-1)).

Studies on the presence of natural and synthetic corticosteroids in bovine urine

Natural and synthetic corticosteroids are widely used in veterinary medicine for their anti-inflammatory properties, but are also illegally used in animal breeding as growth-promoting agents: this latter application in livestock production has been banned within the European Union due to health concerns for the consumer. In this work urine samples collected from bovines experimentally treated with dexamethasone (0.4 mg of dexamethasone 21-disodium phosphate per capita/day for 20 consecutive days) and bovines bred under strictly controlled conditions were investigated for the presence of natural and synthetic corticosteroids, using a simple multi-residue liquid chromatography-tandem mass spectrometry method, developed and validated in accordance with the criteria of the Commission Decision 2002/657/EC. The aim of this work is to investigate the effect of a low dosage and long term dexamethasone treatment on the levels of endogenous corticosteroids in cattle and to evaluate the possible presence of prednisolone residues in bovines bred under strictly controlled conditions. Our findings confirm the high and rapid rate of dexamethasone urinary excretion. Dexamethasone treatment elicited an early reduction of hydrocortisone and cortisone, suggesting the disappearance of these two hormones as an indirect indicator of corticosteroid treatment in cattle. Prednisolone residues were found (concentration interval 0.4-1.4 ngmL(-1)) in urine samples collected from control bovines especially at the slaughterhouse, together with high levels of hydrocortisone and cortisone. Further studies are necessary to find out the reason of unexplained excretion of this hormone in urine samples of untreated bovines.