Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES)

Technique in brief

ICP-AES is a well-established and cost effective technique for multi-element analysis. Samples (in solution) are introduced, as an aerosol, into a plasma (at temperatures in the order of 6000-10,000K). This process effectively coverts the elements present to gaseous atoms (then ions), which are elevated to excited states. As the atoms "relax" to a lower excited or 'ground' state they emit light radiation at characteristic wavelengths. A spectrometer is used to separate the light emitted and is detected using a photo multiplier tube (PMT).

Current instrumentation

The current ICP-AES is a Varian Liberty Series II, which is a sequential instrument.

Applications

ICP-AES is best suited for elements in the low weight percent to parts per million-concentration range and has particular advantages over ICP-MS for some elements such as sodium, potassium, calcium, phosphorous and sulphur. The technique can be applied to the determination of elemental composition of a wide variety of material types including geological, environmental, biological.

Sample requirements

Samples for ICP-AES need be introduced as a solution (a liquid phase). Solid samples need be crushed and dried and a suitable method used to dissolve the material (normally accomplished by open vessel or microwave-assisted digestion in acids or, where necessary by fusion techniques). In most instances the AAC will perform sample digestion.

For further information contact the officer in charge:

Dr Yi Hu