induced coupled plasma Flashcards
what is a plasma
a gas that contains ions and free electrons
what do the free electric charges do?
make the plasma electrically conductive so that it responds strongly to electromagnetic fields
for ICP what is used to produce plasma
argon
is plasma an electrical discharge or a chemical flame
electrical discharge
how is plasma generated
through inductive coupling of free electrons with rapidly oscillating external magnetic field
energy is transferred collisionally to organ molecules
plasma at atmospheric pressure allows what
high temperatures
plasma temperature range between what
6000K and 10000K
why use argon plasma
it is inert
not expensive
obtained at very high purity
first ionisation potential higher than most others
second ionisation potential lower than most others
since the plasma environment is define by the Ar….
most analyte elements are efficiently singly charged
what happens when a time-varying electric current is passed through the coil
it creates a time varying magnetic field around it, which in turn induces electric currents in the rarefied gas, leading to break down and formation of a plasma
are ICP discharges of high or low electron density
high
what does ICP-MS stand for
Inductively Coupled Plasma Mass Spectroscopy
what does ICP-OES stand for
Inductively Coupled Plasma Optical Emission Spectrometry
what does ICP-AES stand for
Inductively Coupled Plasma Atomic Emission Spectrometry
what are ICP-OES and ICP-MS used for
bulk elemental chemical analysis of just about any material or substance
what are the exceptions of the periodic table that ICP-OES and ICP-MS can’t measure
H, O, N, F, Cl
concentrations from what to what can be measured in solution using ICP-OES and ICP-MS
from major to parts per billion and even parts per trillion in solution
what is ICP-AES
a type of emission spectroscopy that uses a plasma to produce excited atoms that emit electromagnetic radiation at a wavelength characteristic of a particular element.
The intensity of this emission is indicative of the concentration of the element within the sample.
what is ICP-MS
technique based on coupling together an ICP as a method of producing ions with a mass spectrometer as a method of separating and detecting the ions.
what is ICP-MS used for
quantitative multi-elemental analysis and stable isotopic rationing
6 advantages of ICP-MS
excellent detection limit wide elemental coverage all elements determined simultaneously wide dynamic range routine technique small size instrument
ICP-MS vs ICP-OES
MS much simpler than the optical emission spectra. Most heavy elements exhibit hundreds of emission lines, but they have only 1-10 natural isotopes in the mass spectrum.
ICP-OES suffers from many overlapping spectral interferences from other elements and a very high background emission from the plasma itself, limiting detection limits.
Detection limits of ICP-MS are three orders of magnitude better than ICP-OES.
