HPLC column balance and protection

Reversed-phase columns are stored in acetonitrile-water after factory testing; the stationary phase of the column may dry out during storage or transport, which can cause changes in the spatial structure of the bonded phase. Therefore, before the new column is used to analyze the sample, be sure to fully equilibrate the column. The equilibration method for the reversed-phase column is: using pure acetonitrile or methanol as the mobile phase, the column is first equilibrated overnight at a low flow rate of 0.2 ml/min (please disconnect the detector!), and then increase the flow rate to 0.8 mL/min. Rinse for 30 minutes to fully equilibrate the packing of the column to its optimal condition. During the equilibration process, the flow rate is slowly increased until a stable baseline is obtained, which guarantees the service life of the column and guarantees reproducibility of the analysis results in later use. Be sure to use the mobile phase and acetonitrile-water miscible. If the mobile phase you are using contains buffer salts, care should be taken to first "transition" with 20 column volumes of a 5% acetonitrile-water mobile phase and then use the mobile phase of the analytical sample until a stable baseline is obtained.

For normal phase columns, silica gel or polar columns require more time to equilibrate. These columns are stored in n-heptane after the factory test. If the polar column requires the use of an aqueous mobile phase, equilibrate with ethanol or isopropanol before using the mobile phase. When using a mobile phase with high viscosity, such as ethanol, isopropanol, and acetic acid, the equilibration time of the column is prolonged or even doubled.