Quantification of clenbuterol in human plasma and urine by liquid chromatography-tandem mass spectrometry

The quantitative determination of clenbuterol in human plasma and urine is of particular interest far various fields such as clinical and forensic research and doping controls. A simple and rapid sample preparation procedure based on liquid-liquid extraction with subsequent re-extraction followed by liquid chromatography and electrospray ionization tandem mass spectrometry allowed the determination of clenbuterol in urine and plasma at detection and quantification limits of 0.1 ng mL(-1) and 0.2 ng mL(-1), respectively, with recoveries ranging from 85-96%. The fast and robust nature of the assay provides a rapid and cost-effective alternative to established procedures utilizing solid-phase extraction strategies.