The Effect Of Argon In Optical Emission Spectrometer
Argon gas is an important analytical condition for spectrometers. It is crucial for the detection of normal use and accurate results. Generally, 99.999% purity of argon is required. Argon creates an isolated environment for excitation because it separates elements such as oxygen and nitrogen from the air. In the detection, oxygen absorbs most of the elemental lines, and is also easily affected by external nitrogen elements, resulting in instability or error in the analysis process. With the isolation of argon, measurement errors are avoided. The direct reading spectrometer fills the optical chamber with argon, which also ensures the cleanness of the optical chamber and avoids the deviation caused by the detection of ultraviolet elements. At the same time, argon gas helps to clean the spark chamber of the excitation chamber and remove the exhaust gas. Impurity of argon will have the following effects:
(1) The purity of ordinary argon is generally not higher than that of four. The main function of argon is to protect the tungsten electrode. Generally, when the spectrum is excited, the transient voltage is high and the current is high, and the excitation temperature is high. If the purity is not enough, the tungsten electrode will be damaged, and some substances with high melting point such as silicon will be insufficiently excited, and there will be many white spots on the metal surface, resulting in inaccurate detection data.
(2) The argon gas is impure, the lens is the most influential, causing lens pollution, affecting the direct reading spectrometer analysis line; in addition, the sound performance is weak when excited, the excitation point is not fully burned, directly affecting the analysis data, and the obtained data deviates from the actual value. ,Inaccurate.
(3) High-purity argon is the main body of the spark chamber shielding gas, and its high purity will form the required "concentration discharge", otherwise it is the so-called "diffusion discharge" causing poor excitation. The more complex the structure of the sample, the more stringent the purity requirements for argon.
(4) The purity of argon used in direct reading spectrometers is generally required to be ≥99.996%.
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