The influencing factors are:

Bubbles. Due to the existence of bubbles in the HPLC system, sharp noise peaks will appear on the chromatogram. In severe cases, the analytical sensitivity will decrease; the bubbles will become larger. When entering the flow path or chromatographic column, the flow rate of the mobile phase will become slow or unstable, causing the baseline to fluctuate. There are three main reasons for the above phenomenon: first, bubbles are often formed in the mobile phase solution due to dissolved oxygen or mixed air; second, the air in the flow path cannot be driven away when the system starts to work; third, when the sample is injected Air was accidentally mixed in from time to time.