Determination of Hormones Residues in Milk by Gas Chromatography-Mass Spectrometry

The article presents the use of gas chromatography-mass spectrometry (GC-MS) technique in a method for the determination of 18 anabolic hormones from synthetic stilbenes, steroids and resorcylic acid lactones (RALs) groups in raw milk and milk powder. Sample preparation consisted of liquid-liquid extraction with diethyl ether and purification by solid phase extraction (SPE). Prior to instrumental analysis, the reaction of derivatisation with the heptafluorobutyric anhydride or N-methyl-N-trimethylsilyltrifluoroacetamide was performed. Method validation was carried out according to the required performance criteria of the Commission Decision 2002/657/EC. The apparent recovery of all analytes at 1 μg L−1 (kg−1) level was ranged between 70.4 and 119.4 % with the coefficients of variation values less than 30 %. The decision limits (CCα) and the detection capabilities (CCβ) were in the range of from 0.11 to 0.44 μg L−1 (kg−1) and from 0.19 to 0.75 μg L−1 (kg−1), respectively. The procedure has been accredited and successfully applied as a screening method for the presence of hormone residues in the study of commercial samples of milk.