This book includes three chapters that discuss the analytical tool called mass spectrometry, which is used to measure the mass-to-charge ratio of ions. Chapter One describes the use of mass spectrometry in the determination of volatile organic compounds in natural matrices and in the characterisation of wood extractives. Chapter Two summarises the investigations by tandem mass spectrometry analysis in biodegradable polymers and the information achieved. Chapter Three discusses the most famous types of commercial Orbitrap analysers, including LTQ Orbitrap, Orbitrap Elite, Q Exactive Orbitrap, and Orbitrap Fusion.