Metabolism studies play an important role at various stages of drug discovery and development. Liquid chromatography combined with mass spectrometry (LC/MS) is to date most powerful and widely used analytical tool for identifying and quantifying drug metabolites. In this respect, the choice of instrumentation currently available is wide with various sets of strength and weaknesses aff ecting data quality and reliability. In this tutorial special feature article, Dr Zhao-Ying Liu from the College of Veterinary Medicine at the Hunan Agricultural University (Hunan, China) describes one of the latest LC/MS instrumentation design namely a hybrid ion trap/time-of-flight MS coupled with liquid chromatography (LC-IT-TOF-MS). This hybrid MS system has successfully integrated ease of operation, compatibility with LC flow rates and data-dependent MSn with high mass accuracy and mass resolving power for drug metabolism studies. Dr Liu interests are centered on the research and development of LC/MS techniques and instrumentation including data processing for pharmacokinetics and veterinary pharmaceutics.