When using high performance liquid chromatography, it is often necessary to do blank solvent interference experiments. When the blank solvent experiment shows that the blank solvent peaks at the component to be tested, must it be the interference caused by the solvent? What should I do if there is a blank solvent interference? You can find the cause and solve it from the following aspects.
System contamination: In this case, double-pass the instrument and flush the instrument overnight with 10% isopropanol at a low flow rate.
Injection port contamination: The injection port is thoroughly cleaned in the sequence of water-acetonitrile-isopropanol-acetonitrile-water.
Residual chromatographic column: there will be residues on the chromatographic column after the high concentration sample is added to the low concentration sample. Rinse the organic phase at a low flow rate overnight before testing or replace it with a new, uncontaminated column.
The sample preparation reagent interferes, the purity of the sample preparation reagent is not pure, or after being placed, impurities will be generated. If the solvent is left for too long and interferes, it can be reconstituted. If there is interference caused by the purity of the reagent, you can replace the reagent with a higher purity grade for the test.
The purity of mobile phase reagents is not enough, in this case, interference peaks are likely to appear at low wavelengths. In this case, you can replace the reagents with higher purity grades or add impurity trapping columns to remove interference.
One-piece cover pad, because the cover pad is bonded with special glue, under special conditions, it will dissolve in the solvent and produce peaks. In this case, the split cover pad can be used.
Before the liquid sample is injected, it needs to be filtered with a filter membrane. Some filter membranes will generate impurities and interfere with peaks. In this case, it is necessary to replace a different filter membrane to solve the problem.
If the interference still cannot be removed after taking the above methods, it is necessary to consider replacing the solvent.