Long-term detection of clenbuterol in human scalp hair by gas chromatography high-resolution mass spectrometry

A method for the detection of clenbuterol in human scalp hair by gas chroma tography-high-resolution mass spectrometry (GC-HRMS) is described. The samp le preparation involved chemical digestion of the protein structure, which was achieved by incubating the hair with 1 M KOH at 70 degrees C. A single extraction step with tert.-butyl methyl ether provided approximately 90% of the analyte, which was dried and derivatized with N-methyl-N-trimethylsily ltrifluoroacetamide (MSTFA) to yield clenbuterol N,O-bis-trimethylsilyl (TM S). Hair was collected from four pregnant women who were therapeutically tr eated with Spiropent(R) (clenbuterol-HCl) and from the infant of one female patient. Hair samples were taken during the application time and two to si x months after completion of clenbuterol administration. The detection limi t of the method was approximately 4 ng clenbuterol/g hair when 25 mg hair m aterial were processed and 2 ng/g for 50 mg hair samples (corresponds to 4 pg per injection). The method allows clenbuterol to be measured retrospecti vely for up to at least six months. The levels of clenbuterol determined in hair ranged from 2 to 236 ng/g, No clenbuterol was found in the hair of th e infant, which was taken five and a half months after delivery. To improve sample preparation, an additional purification step via immune affinity ch romatography (IAC) was integrated. The IAC purified extracts showed reduced biological background interference and an improved limit of detection (0.8 ng/g). (C) 1999 Elsevier Science B.V. All rights reserved.