Detection of testosterone propionate administration in horse hair samples

A sensitive and specific method has been developed to detect semi-quantitatively testosterone in horse hair samples. The method involved a washing step with sodium dodecylsulfate aqueous solution. The mane and tail hair samples (100 mg) were dissolved in 1 mL of sodium hydroxide for 15 min at 95 degrees C in the presence of d3-boldenone used as internal standard. The next three steps involved diethyl ether extraction and a solid phase extraction on Isolute C18 (EC) cartridges eluted with methanol. The residue was derivatized by adding 100 mu L of acetonitrile and 30 RL of PFPA then incubating for 15 min at 60 degrees C. After evaporation, 30 mu L of hexane was added and 2.5 mu L was injected into the column (a bonded phase fused silica capillary column DB5MS, 30 m x 0.25 mm i.d. x 0.25 mu m film thickness) of a Trace GC chromatograph. In order to improve the sensitivity of the method, damping gas flow has been optimized. Testosterone was identified in MS2 full scan mode on the Polaris Q instrument. The assay was capable of detecting less than 1 pg mg(-1). The recovery was close to 90%. The analysis of tail and mane samples collected from a gelding horse having received a single dose of testosterone propionate (1 mg kg(-1)) showed the presence of testosterone in the range of 1-6 pg mg(-1) in hair collected during 5 months after administration. (c) 2007 Elsevier B.V. All rights reserved.