Confirmatory analysis of 17β-boldenone, 17α-boldenone and androsta-1,4-diene-3,17-dione in bovine urine, faeces, feed and skin swab samples by liquid chromatography–electrospray ionisation tandem mass spectrometry

The origin, i.e. natural occurrence or illegal treatment, of findings of 17α-boldenone (α-Bol) and 17β-boldenone (β-Bol) in urine and faeces of cattle is under debate within the European Union. A liquid chromatographic positive ion electrospray tandem mass spectrometric method is presented for the confirmatory analysis of 17β-boldenone, 17α-boldenone and an important metabolite/precursor androsta-1,4-diene-3,17-dione (ADD), using deuterium-labelled 17β-boldenone (β-Bol-d3) as internal standard. Detailed sample preparation procedures were developed for a variety of sample matrices such as bovine urine, faeces, feed and skin swab samples. The method was validated as a quantitative confirmatory method according to the latest EU guidelines and shows good precision, linearity and accuracy data, and CCα and CCβ values of 0.1–0.3 and 0.4–1.0 ng/ml, respectively. Currently, the method has been successfully applied to suspect urine samples for more than a year, and occasionally to faeces, feed and swab samples as well. Results obtained from untreated and treated animals are given and their impact on the debate about the origin of residues of 17β-boldenone is critically discussed. Finally, preliminary data about the degree of conjugation of boldenone residues are presented and a simple procedure for discrimination between residues from abuse versus natural origin is proposed.