With the rapid development of the national economy, liquid chromatography is widely used in the detection of petrochemical products, food, synthetic drugs, water resources, biochemical products and environmental pollutants. During the use of the liquid chromatograph, we often encounter the phenomenon that the liquid chromatograph user's positive and negative reversed-phase chromatography system interacts with each other. However, due to improper operation, the column is often inadvertently damaged, and the contamination of the liquid chromatography system is aggravated. Leading to the analysis work, Lu Chuang analytical instrument engineers listed the basic process of replacement work for your reference:

1. First use n-hexane (silica gel column) to balance the chromatographic system including the normal phase column (to ensure that the baseline is straight within 20 minutes, no peak appears);
2. Remove the silica gel column and seal it for storage;
3. Short the injection valve to the detector and flush the chromatographic system with isopropanol for 10 minutes (flow rate 1 ml/min). During this time, the injection valve is empty three times;
4. Change the methanol (or the eye) to the system for 20 minutes (flow rate 2ml/min), during which time the injection valve is empty three times;
5. Install the reversed-phase column, adjust the flow rate to 1 ml/min, and rinse the system with methanol (or eye) until the system is equilibrated;
6. Enter the three-needle standard and check whether the area and retention time are repeated. If not, continue to rinse until repeated.