NS Notes · Interactive Series
Interactive animations explaining how a mass spectrometer works — from generating ions, to separating by mass, to detection
This series is organized into three main stages, following the order in which a mass spectrometer operates. Each page is an interactive animation you can drag, click, and adjust to see the real working principle. Pick any topic to begin.
Turning sample molecules into charged ions before analysis.
Electrospray Ionization (ESI) Sprays solution through a high-voltage needle into charged droplets (most common in LC-MS) Matrix-Assisted Laser Desorption/Ionization (MALDI) Fires a laser at sample embedded in a matrix (ideal for proteins and large biomolecules) Electron Ionization (EI) Electrons strike molecules and shatter them into fragments (paired with GC-MS)Separating ions by their mass-to-charge ratio (m/z) using different principles.
Quadrupole Filters ions by m/z using an oscillating electric field; only ions with stable trajectories pass through Time-of-Flight (TOF) Separates by flight time — lower m/z ions arrive faster, higher m/z ions arrive slower (Linear, Reflectron, Spiral) Ion Trap Traps ions and selectively ejects them according to m/z (3D Paul trap and Linear trap) Magnetic Sector A magnetic field bends the ion path according to mass Fourier-Transform Ion Cyclotron Resonance (FT-ICR) Ions orbit in a magnetic field; inducing an image current that is Fourier-transformed into frequency information Orbitrap Ions orbit a central spindle; the axial oscillation frequency encodes m/zConverting the separated ions into an electrical signal.
Electron Multiplier Multiplies electrons in a chain reaction across several dynodes Microchannel Plate (MCP) Millions of microscopic channels amplify ion-induced electron cascades in parallel; fast and well suited for TOF Faraday Cup A metal cup collects ions and measures the current directly; simple and stable