Emission Spectroscopy

Compounds of certain metals vaporized in flames produce distinctive colors. Scientists of the 19th century, such as the German chemist Robert Wilhelm Bunsen, showed that the optical spectra of these colored flames contain lines or bands at wavelengths, characteristic of the particular elements. Quantum mechanics proved that these lines and bands arise from electronic transitions in specific atoms or molecules.

Optical emission spectrometry is the extrapolation of this research. Originally, a sample solution is introduced into the flame as a fine spray. The intensities of the characteristic spectral lines of the elements are measured with a filter spectrometer or simple monochromator with electronic detection and readout.

Measurement theory

Modern inductively coupled plasma atomic emission spectroscopy (ICP-AES) relies on the same principles to determine amounts of a wide range of elements: A solution of the selected samples and a set of calibrating solutions is prepared, which contain known concentrations of the elements to be analyzed. The sample solution and the calibrating solutions are sprayed into the plasma, and the intensities of appropriate emission lines are recorded. For each element, calibration graphs, which contain the emission intensities, are prepared. The concentrations of the elements in each sample solution are determined from these graphs.  

Benefits
  • High precision
  • High speed
  • High sensitivity and accuracy
  • Freedom from chemical interferences  
Examples of use

A large number of elements in biological materials play an important role in the nutritional, toxicological and environmental aspects of human health. ICP-AES is applied for:

  • Detection of micronutrient and toxic elements in agricultural samples such as soil, plant tissue, grains, forages, animal feeds or fertilizers etc.
  • Analysis of samples in agriculture, medicine, biology, geology, environment, foods and beverages, metallurgy, organics and water