Atomic spectroscopy is an analytical procedure used to determine the composition of elements in a sample (gas, liquid, or solid) by analyzing its electromagnetic spectrum or mass spectrum. There are different variations of atomic absorption spectroscopy, emission, fluorescence, and mass spectroscopy. There are several nuclear absorption spectroscopy techniques, and it is essential to select the most appropriate to achieve accurate, reliable, and real-world results. This is because each method has its strengths and limitations.
Here is a basic overview of some of the atomic spectroscopy techniques and how you can select the best analytical problems technique.
Flame Atomic Absorption Spectroscopy (Flame AA)
When a ground state atom absorbs light energy of a specific wavelength, it becomes excited. The amount of light energy absorbed at particular wavelengths increases the number of atoms of the selected elements in the light path. The relationship between the amounts of light an element absorbs and the concentration of the analytes present can determine sample concentrations by measuring the amount of light they absorb.
Performing flame AA requires a source of light, an atom source, and monochromator to isolate different wavelengths, and a detector to measure the light accurately. The most commonly used light source is a hollow cathode lamp or electrodeless discharge lamp.
The atom source must produce free analyte atoms from the sample. Heat mostly in the form of air/acetylene or nitrous-oxide flame is usually used as a source of energy to produce free particles. The limitation of the flame AA technique is that only a few samples reach the flame and the atomized samples pass through the light path quickly reducing the method’s sensitivity.
Graphite furnace atomic absorption spectroscopy (GFAA)
With the graphite furnace Atomic Spectroscopy technique, the sample is introduced to a graphite tube, which is heated in several carefully programmed steps to eliminate the solvent and other components and make the atoms free. All the analyte is atomized, and the atoms are retained within the tube for an extended period unlike in the flame AA. This gives the system more time to sense and detect the atoms improving sensitivity and detection limits. Graphite furnace analysis takes much longer than flame AA, and the technique determines fewer elements. However, with enhanced sensitivity, GFAA can be used to analyze tiny samples.
Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES)
Inductively coupled plasma optical emission spectroscopy is the measurement of light produced by elements introduced into an ICP source (ICP is argon plasma maintained by ionized argon gas). The measured light emitted is compared to intensities of known concentration standards to determine the concentration of elements in the unknown sample. There are two viewing ways, axial or radial. Axial viewing provides better detection limits compared to radial viewing. This offers the best detection capabilities and wide working ranges.
The most effective criteria for selecting an Atomic Spectroscopy technique to consider the detection limit, analytical working range, ease of use, and the availability of the proven methodology. Atomic spectroscopy techniques are essential in providing a simple and accurate concentration of vital elements in agriculture, food processing, and pharmaceutical industries.