Confirmatory method for the determination of nandrolone and trenbolone in urine samples using immunoaffinity cleanup and liquid chromatography–tandem mass spectrometry

Multiresidue Determination of the Anabolic-Agent Residues Steroids, Stilbenes, and Resorcylic Acid Lactones in Bovine Urine by GC-MS/MS with Microwave-Assisted Derivatization

In this work, a GC-MS/MS method was developed for the determination of anabolic-agent residues in bovine urine. The optimized sample preparation was as follows: enzymatic hydrolysis by β-glucuronidase-sulfatase enzyme from Helix pomatia for 16 h at 37.5 °C, liquid-liquid extraction with diethyl ether, solid-phase extraction with HLB and aminopropylsilane cartridges, and microwave-assisted derivatization using 25 μL of MSTFA/NH₄I/ethanethiol and full microwave power for 2 min. The method was validated according to Decision 657/2002/EC, Codex Alimentarius, and Manual da Garantia da Qualidade Analítica guidelines. The acceptability criteria for quantitative analysis were met for α-ethinylestradiol, α-nandrolone, β-estradiol, β-zearalanol, β-zearalenol, drostanolone, ethisterone, dienestrol, diethylstilbestrol, hexestrol, megestrol, methyltestosterone, and zearalenone. The analytes α-zearalenol, α-zearalanol, and norethandrolone were validated for qualitative analysis.

Simultaneous determination of capsaicin and dihydrocapsaicin for vegetable oil adulteration by immunoaffinity chromatography cleanup coupled with LC-MS/MS

Capsaicin and dihydrocapsaicin were selected as adulteration markers to authenticate vegetable oils. In this study, a method of immunoaffinity chromatography (IAC) combined with liquid chromatography-tandem mass spectrometry was established for the determination of capsaicin and dihydrocapsaicin in vegetable oils. In this method, immunosorbents were obtained by covalently coupling highly specific capsaicinoid polyclonal antibodieswith CNBr-activated Sepharose 4B, and then packed into a polyethylene column. In this paper, the major parameters affecting IAC extraction efficiency, including loading, washing and eluting conditions, were also investigated. The IAC column displayed high selectivity for capsaicin and dihydrocapsaicin with the maximum capacity of 240ng. The limit of detection (LOD) and limit of quantification (LOQ) for capsaicin were calculated as 0.02 and 0.08μgkg(-1), and for dihydrocapsaicin were 0.03 and 0.10μgkg(-1). The recoveries of capsaicin and dihydrocapsaicin in oil samples were in the range of 87.3-95.2% with the relative standard deviation (RSD) of less than 6.1%. The results indicated that capsaicinoid compounds could not be found in edible vegetable oils. Therefore, the proposed method is simple, reliable and adequate for routine monitoring of capsaicinoid compounds in vegetable oils and has an excellent potential for detection of adulteration with inedible waste oil.

Immunoextraction of testosterone and epitestosterone from human urine sample based on polyamidoamine modified silica

Polyamidoamine dendrimer (PAMAM) is one of a number of dendritic polymers with precise molecular structure, highly geometric symmetry, and a large number of terminal groups. The polyamidoamine modified silica was synthesized with microwave assisted protocol. Anti-epitestosterone monoclonal antibodies were immobilized onto the PAMAM grafted silica and prepared an off-line immunoextraction column that applied in the extraction of testosterone and epitestosterone. The results showed that the affinity activity of the anti-epitestosterone monoclonal antibodies was remained at high level after immobilization. It was satisfactory to apply this new type of immunoextraction column to analyze testosterone and epitestosterone in spiked urine sample.

Improvement of estradiol esters monitoring in bovine hair by dansylation and liquid chromatography/tandem mass spectrometry analysis in multiple reaction monitoring and precursor ion scan modes

RATIONALE

The control of forbidden anabolic practices in cattle in the European Union has become challenging since endogenous compounds such as estradiol derivatives can potentially be used as growth promoters. Due to the great difficulty in establishing a reference threshold value for endogenous steroids, the direct detection of steroid esters in hair is an efficient strategy for the detection of 'natural' steroid abuse in cattle.

METHODS

The present study aimed to develop and validate according to the current European standards a specific liquid chromatography/tandem mass spectrometry (LC/MS/MS) analytical strategy to monitor estrogen esters in bovine hair. The analysis was performed by positive ion electrospray ionisation (ESI+) after dansylation. Two acquisition modes were then assessed: single reaction monitoring and precursor ion scanning.

RESULTS

The results showed that the introduction of a dansylation step strongly improves the sensitivity of the detection of estradiol-17-esters by LC/(ESI+)-MS/MS. The CCα values are in the range 1-10 ng g(-1) after optimisation, except for estradiol decanoate for which the derivatisation is not efficient. In addition, this LC/MS/MS approach makes it possible to carry out a precursor ion scan to screen for the presence of these estradiol 17-esters in hair samples.

CONCLUSIONS

Based on the specific product ions, i.e. m/z 255 in native conditions or m/z 171 after dansylation, this strategy has the advantage of detecting any (un)known estradiol ester and of giving access to the [M + H](+) ion of the suspected ester through only a single analysis.