Quadrupole mass spectrometers are advanced analytical instruments used to measure the mass-to-charge ratio of ions with high precision. They employ four parallel rods (the quadrupole) to create an oscillating electric field that selectively allows ions of a specific mass-to-charge ratio to pass through to the detector while filtering out others. QMS instruments are widely used for qualitative and quantitative analysis of chemical compounds, trace elements, and isotopes. They are commonly applied in chemistry, pharmaceuticals, environmental monitoring, food testing, and materials science, offering fast scanning, high sensitivity, and reliable results for complex sample analysis.