Mass spectrometry is a technique used to measure the mass-to-charge ratio of ions. It is commonly used in analytical chemistry to identify the chemical composition of a sample by ionizing and then separating the ions based on their mass-to-charge ratio. Mass spectrometry is used in a wide range of applications, including determining the molecular weight of compounds, analyzing biomolecules such as proteins and peptides, and detecting and quantifying trace amounts of substances in environmental samples. It is a powerful tool for research in fields such as pharmaceuticals, environmental science, and proteomics.