The working principle of atomic absorption spectrophotometer

Atomic absorption spectrometer, also known as atomic absorption spectrophotometer, is used to analyze metal elements according to the effect of ground state atomic vapor on characteristic radiation absorption. It can detect trace or trace elements sensitively and reliably.

Atomic absorption spectrophotometer is generally composed of four parts, namely light source (monochromatic sharp line radiation source), sample atomizer, monochromator and data processing system (including photoelectric converter and corresponding detection device).

Elements are heated and atomized in a pyrolytic graphite furnace to form ground-state atomic vapor, which selectively absorbs the characteristic radiation emitted by a hollow cathode lamp. In a certain concentration range, the absorption intensity is directly proportional to the content in the test solution. Its quantitative relationship can be used Lambert-Beer law, A = LG I / O = lgT = KCL, formula I is the intensity of transmission light; I0 is the intensity of emission light; T is the transmission; L is the light path through the atomizer (length), the L value of each instrument is fixed; C is the concentration of the sample measured; therefore A = KC.

A device for determining the absorbance of an element by its atomic vapor through resonance radiation of the element to be measured is called an atomic absorption spectrophotometer, an atomizer, an optical system, and a detection system. It is mainly used for the analysis of trace element impurities. It has three main advantages: high sensitivity, good accuracy and good selectivity. It is widely used in the analysis of trace elements in special gases, organometallic compounds and metal alkoxides. However, the measurement of each element requires a corresponding hollow cathode lamp, which is inconvenient for testing.

Manufacturers of atomic absorption spectrophotometer