Wilson R T, Groneck J M, Holland K P, Henry A C
U.S. Department of Agriculture, Food Safety and Inspection Service, Midwestern Laboratory, St. Louis, MO 63115.
J AOAC Int. 1994 Jul-Aug;77(4):917-24.
A gas chromatographic/mass spectrometric procedure is described for the quantitation and confirmation of clenbuterol residues from cattle, sheep, and swine tissues. After liquid-liquid extraction and derivatization with phosgene in an aqueous pH 10.1 buffer, the cyclic oxazolidone derivative is quantitated with a clenbuterol analogue as internal standard (NAB-760 Cl). Confirmation is accomplished by comparison of ion ratios with those of a pure synthesized standard of clenbuterol oxazolidin-3-one obtained by selected ion monitoring, electron ionization gas chromatography/mass spectrometry on a benchtop instrument. Statistical information based on a series of standard curves for fortified tissues is included to describe method performance. Ion ratio variations were under 15%, and coefficients of variation for spiked tissue standard curves were above 0.997. Recoveries averaged 87.1 +/- 6.6% for liver tissues across all 3 species and 67.1 +/- 3.8% for muscle tissue across all 3 species.
