Valve core/one-way valve

Valve core/one-way valveThe injection valve is a key component used in chromatographic analysis to accurately introduce samples into the chromatographic system. Its functions include controlling sample volume, switching mobile phase paths, and reducing cross contamination;

Valve core/one-way valveClassified by operation method:

Manual injection valve: By manually rotating the valve core to switch the flow path, it is suitable for laboratory small batch analysis, such as Agilent's 7725i (stainless steel) and 9725i (PEEK material) valves;

Automatic injection valve: integrated into the automatic injector, achieving high-throughput analysis and improving repeatability through program control;

Classified by application scenario:

Gas chromatography (GC) injection valve: such as a six way valve, used for gas or liquid sample injection, paired with a microinjector (10 μ L for packed columns and 1 μ L for capillary columns);

Liquid chromatography (HPLC) injection valve: such as high-pressure manual injection valve (pressure resistance up to 1200 bar), suitable for preparative chromatography of high flow rate and large volume samples.

Operation mode and precautions:

1. Typical operating mode 1. Split injection:

Suitable for high concentration samples, most of the sample gas is released through the diversion outlet, and only 1% -5% enters the chromatographic column, reducing column load;

Choose a liner with reduced diameter or glass wool to ensure uniform gasification and prevent solid residue;

2. Non split injection:

Suitable for trace analysis, by delaying the opening time of the diversion valve to allow all samples to enter the chromatographic column;

Maintenance and common problems

1. Pollution treatment: Regularly backwash or replace the sieve plate to avoid peak splitting caused by column head pollution;

2. Sealing inspection: Use a soap film flowmeter to detect leaks in the diversion gas path and ensure stable flow;