ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectrometer) uses ICP (inductively coupled 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. This technique is also referred to as ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry).

In plasma emission spectroscopy, a sample solution is introduced into the core of an inductively coupled argon plasma (ICP) at a temperature of approximately 8000°C. At this temperature all elements become thermally excited and emit light at their characteristic wavelengths. This light is collected by the spectrometer and passes through a diffraction grating that serves to resolve the light into a spectrum of its constituent wavelengths. Within the spectrometer, this diffracted light is then collected by wavelength and amplified to yield an intensity measurement that can be converted to an elemental concentration by comparison with calibration standards. This measurement process is a form of atomic emission spectroscopy (AES).

Advantages of ICP-AES Spectroscopy

1. Many elements (up to 70 in theory) can be determined simultaneously in a single sample analysis.
2. Instrumentation is readily amenable to automation, thus enhancing accuracy, precision and throughput.
3. High instrumental productivity permits very competitive pricing of analytical packages, thus giving the explorer a significant return on a relatively small expenditure.
4. Electronic data capture and transfer to the LIMS ensures that no manual data transcription errors occur.
5. ICP-AES offers a useful working range over several orders of magnitude

Limitations of ICP-AES Spectroscopy

1. Complex instrumentation requires highly skilled staff both for routine operations and for repairs and
2. The emission spectra are complex and inter-element interferences are possible if the wavelength of the element of interest is very close to that of another element; for example, one of the phosphorus wavelengths suffers from both copper and aluminum interference.
3. As with atomic absorption spectroscopy, the sample to be analysed must be digested prior to analysis in order to dissolve the element(s) of interest.
4. Rigid temperature and humidity control is required for best stability of the spectrometer.

External links

• ICP-AES