Development of a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of glucocorticoid residues in edible tissues of swine, cattle, sheep, and chicken

Analysis of corticosteroids in samples of animal origin using QuEChERS and ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry

A rapid and sensitive method for the confirmatory analysis of eight synthetic corticosteroids (betamethasone, dexamethasone, prednisolone, 6-methylprednisolone, triamcinolone, flumethasone, beclomethasone, fluocinolone acetonide) is proposed. The method is useful for detecting illegal treatments in different animal species. It consists of an extraction and cleanup using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) strategy. Quantitative determination is achieved by ultrahigh-performance liquid chromatography coupled to high-resolution mass spectrometry with heated electrospray ionization in negative mode. Quantification is performed using surrogate matrix-matched standard calibration curve with dexamethasone-D₄ as the internal standard. The method was validated for analyzing liver samples according to the criteria established by Decision 2002/657/EC. Linearity was assessed in the 1-10 μg kg^-1 range and linear correlation coefficients were over 0.99 for all the analytes. CCα ranged from 0.04 to 0.16 μg kg^-1 for substances without maximum residue limit. The method allows confident quantification and confirmation of corticosteroids in liver samples, and its simplicity makes it suitable for analyzing large numbers of samples.

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.

A highly sensitive method for the quantification of fludrocortisone in human plasma using ultra-high-performance liquid chromatography tandem mass spectrometry and its pharmacokinetic application

A simple and high sensitive ultra-high-performance liquid chromatography tandem mass spectrometry method for the determination of fludrocortisone in human plasma was developed and validated as per guidelines. The analyte and internal standard (IS), fludrocortisone-d5 , were extracted from human plasma via liquid-liquid extraction using tert-butyl methyl ether. The chromatographic separation was achieved on a Chromolith RP18e column using a mixture of acetonitrile and 2 mm ammonium formate (70:30, v/v) as the mobile phase at a flow rate of 0.7 mL/min. Quantitation was performed on a triple quadrupole mass spectrometer employing electrospray ionization technique, operating in multiple reaction monitoring and positive ion mode. The precursors to product ion transitions monitored for fludrocortisone and IS were m/z 381.2 → 343.2 and 386.2 → 348.4, respectively. The assay was validated with linear range of 40-3000 pg/mL. The intra- and inter-day precisions (relative standard deviation) were within 0.49-7.13 and 0.83-5.87%, respectively. The proposed method was successfully applied to pharmacokinetic studies in humans.

LC-MS/MS determination of betamethasone and its phosphate and acetate esters in human plasma after sample stabilization

Two specific liquid chromatography-mass spectrometric (LC-MS/MS) assays were developed and validated for the determination of betamethasone (BET), and its acetate (BA) and phosphate (BP) esters. The plasma and the blood used for the development and validation of these two methods were previously stabilized. Liquid-liquid extraction techniques were used after the addition of prednisolone as internal standard (IS). Samples were chromatographed using C8 column, while mass detection was carried out by electrospray ionization in the positive mode (ESI+). The method was proved linear over a working range 0.50-50.00 ng/ml for BET (r(2)>0.99), while BA linear range was 1.0-20.0 ng/ml (r(2)>0.99). Sensitivity was determined as 0.50 ng/ml for BET and 1.00 ng/ml for BA. Betamethasone phosphate LC-MS/MS method involved solid phase extraction after the addition of prednisolone phosphate as (IS). Separation was carried out using C18 column, while detection was by ESI+. The method showed good linearity over the working range 2.0-200.0 ng/ml (r(2)>099). Both methods were applied to determine BET, BA and BP in plasma samples obtained for pharmacokinetics studies in human.