Possibility: 1, if the stigma is polluted, it can be washed with a high proportion of organic phase. If not, it can be backwashed or repaired with stigma. I feel that it is effective to repair stigma. 2. The sample volume is greater than the saturation of the chromatographic column. The sample size can be reduced. 3. Impurities in the sample, two peaks are superimposed together.