¹Department of Pharmacology & Toxicology, ²Clinical Research Center, and ³Space Medicine and Life Science Research Center, Morehouse School of Medicine, Atlanta, GA, USA

A simple and sensitive procedure utilizing GC-MS for the identification and quantitation of clenbuterol in plasma and urine has been developed. This improved method utilizes trimethylboroxine for the derivatization of clenbuterol thereby yielding abundant diagnostic ions with high m/z values.

Linear quantitative response curves have been generated for derivatized clenbuterol over a concentration range of 5-200 ng/mL. The extraction efficiency at four representative points of the standard curve exceeded 90 % in both specimen types (plasma and urine). Linear regression analyses of the standard curve in both specimen types exhibited correlation coefficients ranging from 0.996 to 1.000. The LOD and LOQ values for plasma specimens were determined to be 0.5 and 1.5 ng respectively. For urine specimens, LOD and LOQ values were 0.17 and 0.6 ng, respectively. Precision and accuracy (within-run and between-run) studies reflected a high level of reliability and reproducibility of the method. In addition to its reliability, sensitivity, and simplicity, the procedure requires less time, only one mL of sample, and minimal amounts of extraction solvents.

The applicability of the method for the detection and quantitation of clenbuterol in biological tissues such as kidney, lung, and liver samples, was demonstrated successfully.