2020年1月13日星期一

Why Does Baseline Drift Appear In HPLC Column?

The sample shall be dissolved as much as possible in solvents that are mutually soluble with the mobile phase. Except for special designation, the resolution of the sample HPLC column may be reduced if it is dissolved using a strong solvent. Besides, the sample solution shall be pre-filtered using a needle filter before injection. Frequent changes in the composition of the mobile phase will accelerate the reduction of column efficiency.
HPLC column is filled with high-pressure slurry and can withstand high pressure. In order to obtain the best separation effect, please do not exceed 200kgf when using, and avoid the sudden rise or change of pressure, otherwise, it will cause the destruction of silica gel filler and reduce the service life of the chromatographic column. The maximum operating temperature shall not exceed 60°C except for special requirements.
Reason
① Column temperature fluctuates. (Even small changes in temperature can cause baseline fluctuations. They usually affect differential detectors, conductivity detectors, lower-sensitivity UV detectors, or other photoelectric detectors.)
② The mobile phase is not uniform. (Baseline drift caused by changes in mobile phase conditions is greater than temperature-induced drift.)
③ The flow cell is polluted or has gas.
④ Detector outlet is blocked. (The high pressure caused the flow cell window to rupture, resulting in a noise baseline.)
⑤ Improper mobile phase ratio or flow rate change
⑥ The column equilibrium is slow, especially when the mobile phase changes.

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