atomemålingsmetoder

Atomemålingsmetoder, also known as atomic absorption spectroscopy (AAS), is a widely used analytical technique for determining the concentration of a specific element in a sample. The method is based on the absorption of light by free atoms in the gaseous state. The sample is atomized, typically by flame or electrothermal methods, and the resulting atoms absorb light at specific wavelengths characteristic of the element. The amount of absorbed light is proportional to the concentration of the element in the sample.

Flame AAS is the most common method, where the sample is introduced into a flame, usually acetylene-air or nitrous oxide-acetylene. The flame temperature is controlled to ensure complete atomization and minimal ionization of the atoms. The light source is a hollow cathode lamp, which emits light at the specific wavelength of the element being analyzed. The absorbed light is measured using a photomultiplier tube, and the signal is processed to determine the concentration of the element.

Graphite Furnace AAS (GFAAS) is another popular method, particularly for trace analysis. In this technique, the sample is introduced into a graphite tube, which is heated to high temperatures to atomize the sample. The light source and detection system are the same as in flame AAS. GFAAS offers higher sensitivity and lower detection limits compared to flame AAS.

Both methods have their advantages and limitations. Flame AAS is simpler and faster, making it suitable for routine analysis. GFAAS, on the other hand, offers higher sensitivity and is ideal for trace analysis. The choice of method depends on the specific requirements of the analysis, including the type of sample, the element to be analyzed, and the desired detection limits.