New approach to derivatisation for oestradiol esters detection in animal blood plasma using negative chemical ionisation GC-MS.

In 1996, the EU prohibited the use of substances with anabolic action for food-producing animals (EU Directive 96/22/EC). In cases of illegal use of steroid hormones, these substances are usually applied to the animals in the form of esters. The reliable determination of intact steroid esters in animal tissues or body fluids is an unequivocal proof of illegal treatment of animals with EU prohibited anabolic substances.

Determination of testosterone esters and nortestosterone esters in animal blood serum by LC-MS/MS.

A sensitive and robust confirmatory method for determination of steroid esters in blood serum is essential for reliable monitoring of possible illegal use of steroid hormones as growth promoters in meat production. A previously used sample preparation methodology was improved. The procedure consists of protein precipitation and removal of phospholipids by dispersive SPE Supel™ QuE Z-Sep (Sigma-Aldrich) followed by clean-up on alumina column and LC-MS/MS measurement.

Determination of testosterone esters and estradiol esters in bovine and porcine blood serum.

Monitoring of steroid esters in blood serum is desirable in order to detect the possible illegal use of natural hormones as growth promoters. A method for the determination of testosterone propionate, testosterone benzoate, testosterone isocaproate, testosterone decanoate and estradiol benzoate in bovine and porcine blood serum was developed. The procedure consists of protein precipitation and removal of phospholipids using a HybridSPE®-Phospholipid column followed by clean-up on a hydrophilic modified styrene polymer Supel-Select HLB column and LC-MS/MS measurement.

Observation of residues in tissues of chickens exposed to low dietary concentrations of chloramphenicol.

To investigate potential residues in tissues arising from naturally occurring low levels of chloramphenicol in plant material, feeding studies were conducted with chickens. A common chicken feed was prepared containing 0, 10, 50 and 200 μg kg chloramphenicol and levels were confirmed by LC-MS/MS. Four separate groups of broiler chickens, eight animals in each group, were fed all their 35-day life with this contaminated feed.