Evaluation of nandrolone and ractopamine in the urine of veal calves: liquid chromatography‐tandem mass spectrometry approach

Abstract

Research articles LC-MS/MS technology allows the direct detection of glucuronoconjugated metabolites. PI scan, NL scan and SRM methods, have demonstrated to be useful for the detection of unknown unpredicted and predicted glucuronide MTD metabolites in metabolic studies. Thirteen glucuronide metabolites were observed, and one of them was resistant to enzymatic hydrolysis, not detectable using the traditional GC-MS strategies. Sport supplements may contain steroids never approved for therapeutic use. In this study, 18 sport supplements purchased online underwent organic solvent extraction and subsequent isolated steroid tested for intrinsic androgen bioactivity. Many were found to be strong androgens. These potent pharmacologically active steroids are being used without regulatory control or consumer awareness of their potential adverse effect. Avidin-biotin technology was used for the implementation of an enzyme-linked immunosorbent assay (AB-ELISA) as a sensitive method for the detection of anabolic androgenic steroids (AAS) present in dietary supplements. Assembled AB-ELISAs were characterized and used for detection of various AAS in 49 samples of counterfeit dietary supplements. The concordance between UHPLC-MS and the CR corrected data from AB-ELISA indicated the potential of this method even to quantification of some steroids. Nandrolone (anabolic steroid) and ractopamine (β-adrenergic agonist) are used quite frequently in food-producing livestock, but little is known about their synergic action when they are administered together. The objective of this study was to determine levels after experimental treatment of bovines with both of the above-mentioned drugs. For this purpose two specific analytical methods based on liquid chromatography-tandem mass spectrometry were developed. The use of tandem yeast and mamma-lian cell in vitro androgen bioassays to detect androgens in internet-sourced sport supplements 545-552 We evaluated the effectiveness of drugs testing using hair and nails and the feasibility of determining when drugs were ingested by measuring the time courses of drug concentrations in hair and toenails after single administrations of various drugs. For most basic compounds, the maximum concentrations in hair segments tended to be higher than those in nails. Nails were an effective specimen to detect neutral and weakly acidic compounds. In this work, we aimed to develop a new, simple and confident sensory platform for cocaine detection. For the fabrication of this test system, surface of μ-well plates was modified with quantum dots (QDs) and then cocaine-binding aptamer modified gold nanoparticles (Apt-AuNP) were covalently attached to the QDs. Detectable signals were obtained owing to the target-induced conformational change of aptamer which gives rise to close interaction of QDs with their quencher, AuNPs. Hence, decrease in fluorescence intensity as a cocaine response was recorded. The developed test system-called as Aptamer Folding based Sensory Device, (AFSD)-was evaluated in terms of main a...

Assessment of the withdrawal period for ractopamine hydrochloride in the goat and sheep

“…pH was adjusted 6.8-7 using with 0.1 M NaOH. After filtration through a 0.20 µm filter, the solution of ractopamine was ready to use for injection (11). One milligram of the drug was intravenously injected into the jugular veins of goats and sheep.…”

“…Analysis of the drug and drug residues in the liver was performed using a Shimadzu HPLC LC-6AD pump with a PDA detector. Optimization and validation of the HPLC method were modified with the mobile phase consisted of acetonitrile: aqua pro chromatography reagent (30:70) containing 0.1% phosphoric acid at pH 3.8 (11)(12)(13). A reverse-phase ODS C 18 column was used, and the detector was set at 225 nm.…”