Grafietfurnaces

A graphite furnace is a laboratory instrument used for the quantitative determination of elements, particularly metals, in a sample. It employs a graphite tube, which is heated to very high temperatures, typically between 2000 and 3000 degrees Celsius. This high temperature is crucial for atomizing the sample, meaning it breaks down the chemical compounds in the sample into individual atoms. The graphite tube is heated electrically, often using a stepped temperature program to control the atomization process.

The sample, usually a small liquid volume, is introduced into the graphite tube. The furnace then goes through a series of stages: drying, charring (or ashing), and atomization. During the drying stage, the solvent is evaporated. Charring removes organic matrix components, leaving behind the analyte of interest. Finally, during atomization, the analyte is converted into a vapor of free atoms. As these atoms absorb and then re-emit light at specific wavelengths characteristic of the element, this absorption is measured by an optical spectrometer. The amount of light absorbed is directly proportional to the concentration of the element in the sample. This technique, known as graphite furnace atomic absorption spectrometry (GFAAS) or graphite furnace atomic emission spectrometry (GFAES), offers high sensitivity and requires very small sample volumes.