Chromatographic analysis of hormone residues in food

General and selective isolation procedure for high-performance liquid chromatographic determination of anabolic steroids in tissues

A multi-residue method has been developed for the determination of anabolic steroids in animal tissue. The analytes are extracted from tissue with methanol and the extract is subjected to two solid-phase extractions, one using a non-specific adsorbing material, such as graphitized carbon black (Carbopack B), and the other Amberlite CG-400 I in the OH form. This procedure allowed the neutral anabolics (testosterone, trenbolone and progesterone) to be isolated and separated from the acidic type (phenolic group), such as diethylstilbestrol, oestradiol, zeranol/zearalenone and their respective metabolites. The determination was effected using high-performance liquid chromatography with different detectors (ultraviolet, fluorimetric and electrochemical). Several analytical parameters were studied: chromatographic conditions, recoveries, evaporation step, solvent flow-rate, cartridges reusability, interference of plastic cartridges. For all the anabolics investigated the recoveries were greater than 83.6%.

High performance liquid chromatographic separation of anabolic oestrogens and ultraviolet detection of 17 beta-oestradiol, zeranol, diethylstilboestrol or zearalenone in avian muscle tissue extracts

A multi-residue analysis was developed to discern oestrogens (17 beta-oestradiol or zeranol) used as anabolic drugs and diethylstilboestrol (DES) from the mycotoxins zearalenone and zearalenol. A mixture of 17 beta-oestradiol, oestrone, DES, zeranol, zearalenol, zearalenone and zearalanone was analysed using a 5 micron silica column with gradient elution from hexane to hexane:methanol:2-propanol, 40:45:15 (v/v) and ultraviolet detection at 280 nm. Only six peaks were obtained since zearalenone and zearalanone had identical elution times. Minimum detectabilities were 5-10 ng for the standards. Chicken muscle tissues (2.5 g) were extracted with acetone:water (95:5, v/v). The extracts were spiked with oestradiol and zeranol at 50, 100 or 200 ppb; and DES or zearalenone at 50 ppb; cleaned-up through dual columns of basic alumina and phosphate exchanged AGMP-1 resin and analysed by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Minimum detectability was 10 ng for oestradiol, zeranol, DES or zearalenone when tissues were spiked at 50 ppb. Recoveries were greater than or equal to 86%, greater than or equal to 83%, 60% and 100% for oestradiol, zeranol, DES and zearalenone, respectively.

Application of a capillary gas chromatographic-selected-ion recording mass spectrometric technique to the analysis of diethylstilbestrol and its phosphorylated precursors in plasma and tissues

A method for the analysis of diethylstilbestrol (DES) which is suitable for pharmacokinetic studies has been developed using capillary gas chromatographic (GC) separation and detection with selected-ion mass spectrometry (MS). This technique has been applied to a variety of samples including human plasma samples and extracts of animal tissues including prostate and liver. To investigate the pharmacokinetics of stilphostrol (diethylstilbestrol diphosphate) we have modified the GC-MS method in two ways. One modification involves a dual assay for DES; the first a direct assay, and the second after hydrolysis of a sample with alkaline phosphatase. The difference in these values is the amount of phosphorylated DES present. The other modification separates stilphostrol and DES using a reversed-phase, ion-paired high-performance liquid chromatographic method followed by alkaline phosphatase hydrolysis followed by the GC-MS method. The details of these three methods are described and some representative data are shown.

Determination of residues of anabolic drugs in meat by gas chromatography-mass spectrometry

The residues in meat of seven estrogenic drugs used in anabolic preparations for animal production were analysed as trimethylsilyl ethers by electron-impact gas chromatography-mass spectrometry following a simple clean-up procedure. The compounds under investigation were: 17 beta-estradiol,l diethylstilbestrol,l hexestrol, dienestrol, stilbestrol, ethynylestradiol and zeranol. The method includes extractive homogenization of 10 g of meat in tetrahydrofuran, followed by liquid-liquid partition between acetonitrile and hexane and finally a chromatographic purification step on a small silica gel column. Gas chromatography was carried out on a 10-m glass capillary column coated with SE-54 using a temperature program from 100 to 250 degrees C. The capillary column was connected to the ion source by an all-glass open-split interface with a scavenger gas-line. Detection of anabolic residues was performed with selected ion monitoring on intensive ions in the mass region above m/e 400, resulting in a detection limit of 1-5 ppb (10(9)). Quantitative determinations were performed using dodecyl gallate as an internal standard applying the signal ratio of the drug and the standard.

Sensitive multi-residue method for detection of anabolics in urine and in tisssues of slaughtered animals

A routine procedure is described for the dependable detection of various anabolic residues in tissues or urine contaminated at levels as low as 0.5-10 ppb (10 parts per 10(9)). A suitable extraction and clean-up procedure was developed, permitting adequate recovery (60-80%) of various anabolics from tissue samples (50 g) or urine (50 ml). Following two-dimensional thin-layer chromatography, the presence of the anabolic residues are detected by sulphuric acid-induced fluorescence. The detection limit of most anabolics is of the order of 1-10 ng.

Stable derivatives for the gas chromatographic determination of synthetic anabolic stilbene residues (diethylstilbestrol, dienestrol and hexestrol) in meat and organs of treated cattle in the sub-parts per billion (10(9)) level

A method for the determination of diethylstilbestrol and the related compounds dienestrol and hexestrol residues in meat and organs of treated cattle is described. After extraction and clean-up, these synthetic estrogens are subjected to reaction with pentafluorobenzoyl chloride, which gives very stable perfluoro esters that are suitable for gas chromatographic determination using an electron-capture detector. With the careful clean-up and the very sensitive response of these derivatives, it is possible to reach a limit of detection in the sub-parts per billion (10(9)) range starting with only 5 g of sample.