working principle
The high-purity argon analysis chromatograph is based on gas chromatography separation technology, which achieves quantitative analysis by detecting the differences in physical and chemical properties of trace impurities in high-purity argon gas. The core process is:
Sample introduction: High purity argon gas sample is quantitatively injected into the chromatograph through an injection system (such as a six way valve) and enters the chromatographic column.
Component separation: The chromatographic column is filled with a specific stationary phase (such as molecular sieve, alumina composite material), and separation is achieved by utilizing the boiling point, polarity, or adsorption differences of impurity components (such as H ₂, O ₂, N ₂, CH ₄, CO, CO ₂) under the propulsion of a carrier gas (ultra-high purity argon gas).
Detection and quantification: The separated components enter the detector in sequence and are converted into electrical signals. For example, the argon ionization detector (AID) detects impurity concentration through changes in ionization current, with a sensitivity of up to 0.05 ppm (calculated as nitrogen); The high-frequency argon discharge detector (HFADD) quantitatively analyzes the absorption or enhancement effect of impurity molecules on arc light.
Key component analysis
Gas supply system: including high-purity argon cylinders, pressure reducing valves, and gas flow controllers, ensuring the purity of the carrier gas (≥ 99.999%) and flow stability (± 0.1%), avoiding background interference.
Chromatography column: High temperature resistant and low adsorption materials (such as stainless steel or quartz) are used, filled with highly selective stationary phases, to achieve efficient separation of complex impurity matrices.
Detector:
Argon ionization detector (AID): ionizes argon gas through a high-voltage electric field to detect changes in impurity ionization current, suitable for trace analysis at ppm to ppb levels.
High frequency argon discharge detector (HFADD): It uses high-frequency electromagnetic fields to excite argon discharge, and achieves quantification through the quenching or enhancement effect of impurity molecules on arc light, with a sensitivity of up to 30ppb (calculated as CH ₄).
Control system: Integrated temperature control (accuracy ± 0.1 ℃), programmed heating (rate 0.1-50 ℃/min), and multi valve switching function, supporting automation of complex analysis processes.
Data processing system: Real time acquisition and processing of signals through chromatographic workstations, generation of chromatograms and calculation of impurity concentrations, supporting simultaneous analysis of multiple components.