1. Column temperature fluctuations
Even small temperature changes can cause fluctuations in the baseline, usually affecting the differential detector, conductivity detector, lower sensitivity UV detector or other photoelectric detector. It can be solved by using a column oven to control the temperature of the column and mobile phase and use a heat exchanger before the detector.
2. Uneven mobile phase
The baseline drift caused by changes in mobile phase conditions is greater than the drift caused by temperature. It can be solved by using HPLC grade solvent and the mobile phase should be degassed prior to use.
3. The flow cell is contaminated or gas exists
Flush the flow cell with methanol or other strong polar solvent. If necessary, use 1N nitric acid (do not use hydrochloric acid).
4. Improper flow ratio or flow rate change
Change the ratio or flow rate. To avoid this problem, please check the mobile phase composition and flow rate regularly.
5. There is a strong retention in the sample
It is eluted as a peak of the taro, showing a gradually increasing baseline. It can be solved by using a guard column and, if necessary, periodically flush the column with a strong solvent between injections or during the analysis.