Standard gas is an industry term for leading gas, and standard gas is a standard substance. Standard materials are highly uniform, stable and accurate measurement standards. They have the basic function of reproducing, preserving and transferring the value. They are used to calibrate measuring instruments and measurement processes in the fields of physics, chemistry, biology and engineering measurement.

Whether it is laboratory chromatographic analysis or calibration of online analytical instruments, a large amount of high-quality standard gas is required to accurately calculate the content of components in the product. Therefore, standard gases have been widely used in product quality supervision and quality control, instrument calibration, atmospheric environment monitoring, medical and health, clinical testing, and evaluation of analytical methods.

1. Preparation of standard mixed gas

The standard mixed gas is prepared by using a high-purity gas as a dilution gas and adding one or more other high-purity gases. Standard gas preparation methods mainly include weighing method, partial pressure method, volume method, permeation method, saturation method, electrolysis method, exponential dilution method, flow ratio mixing method, etc.

Standard mixed gas preparation technology

1. Pressure ratio method: measures the pressure of each component and distributes according to the specified concentration.

2. Static volume method: national standard method using static volume gas distribution device.

3. Gravimetric method: uses a high-load precision balance to weigh each gas component.

4. Permeation tube method: uses a small container for raw material liquid and permeable membrane.

5. Mass flow ratio method: uses the flow ratio mixing method for accurate measurement.