Spectrophotometer, namely, flame atomizer and electrothermal atomizer.

An atomic absorption spectrophotometer is used to measure the absorbance of an element by its atomic vapor through the resonance radiation of the element to be measured. It has single beam, double beam, double channel, and multi wave structure. Its basic structure includes light source, atomizer, optical system and detection system. It is mainly used for the analysis of trace elements impurities. It has two main advantages: high sensitivity and good selectivity. It is widely used in the analysis of trace elements in various gases, organometallic compounds and metal alkoxides. However, the measurement of each element requires a corresponding hollow cathode lamp, which is inconvenient for testing.

Atomic absorption spectrophotometer manufacturer atomic absorption spectrophotometer generally consists 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).

There are two main types of atomizer, that is, flame atomizer and electrothermal atomizer. There are many kinds of flames, and the air acetylene flame is widely used nowadays. Graphite furnace atomizer is widely used in electrothermal atomizer, so atomic absorption spectrophotometer, flame atomic absorption spectrophotometer and atomic absorption spectrophotometer with graphite furnace. The atomization temperature of the former is between 2100 ~2400 and ~3000, and the latter is between 2900 C and C.

Flame atomic absorption spectrometer, the use of air-acetylene determination of more than 30 elements, if the use of nitrous oxide-acetylene flame, the determination of more than 70 elements. However, the safety of Nitrous Oxide acetylene flame is poor and its application is not widespread. Air acetylene flame atomic absorption spectrometry can generally detect PPm level (10) and precision is about 1%. Domestic flame atomic absorption spectrophotometer can be equipped with various types of hydride generator (electric heating atomizer), using hydride generator, can determine arsenic (As), antimony (Sb), germanium (Ge), tellurium (Te) and other elements. The general sensitivity is ng/ml (10) and the relative standard deviation is about 2%. Mercury (Hg) can be determined by cold vapor atomic absorption spectrometry.

Graphite furnace atomic absorption spectrophotometer can measure nearly 50 elements. Graphite furnace method, less sample injection, high sensitivity, and some elements can also be analyzed to pg/mL level.

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 of the tested elements 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.

Manufacturers of atomic absorption spectrophotometer