inductively coupled plasma
/ in-DUK-tiv-lee KUP-uld PLAZ-muh /
An inductively coupled plasma is a tiny, ferociously hot fireball of glowing gas — hotter than the surface of the Sun — used to rip samples apart into bare atoms. Picture a torch that runs not on burning fuel but on argon gas stirred into a frenzy by a powerful radio-frequency coil, until the gas itself becomes a self-sustaining flame of charged particles.
More precisely, argon flows through a quartz torch wrapped by a coil carrying a strong radio-frequency current. The oscillating magnetic field drives electrons round and round, smashing into argon atoms and ionising them; this avalanche sustains a stable plasma at roughly 6000 to 10000 kelvin. A sample mist injected into its core is instantly dried, vaporised, atomised, and even ionised.
It matters because that extreme, stable heat excites almost every element strongly and evenly, which is why the plasma is the heart of modern multi-element instruments. The honest cost is that ICP gear is expensive and consumes a lot of argon, so it lives in well-funded labs rather than on every benchtop.
A water sample misted into an argon ICP torch glows a brilliant white-blue at around 7000 K; in that instant every dissolved metal is atomised, ready to emit its own light to a detector or be counted by a mass spectrometer downstream.
An argon torch hotter than the Sun's surface, used to atomise samples completely.
ICP is a heat source, not a whole technique. Pair it with a light detector and you get ICP-OES (optical emission); pair it with a mass spectrometer and you get ICP-MS. The plasma is the same; what reads it differs.