9 Factors contributing to HPLC baseline drift
ChaoYing(Emily) Y.
Laboratory Consumables| HPLC | Vial|Centrifuge Tubes|Cap&Septa|Head Space Vial|Vial Rack|Syringe Filter|Sales Assistant
**Information originally published in the 《HPLC Troubleshooting Guide》 by SIGMA-ALDRICH
1. Effect of column temperature
The effect of column temperature for some detectors, especially the oscillometric refractive detector or high sensitivity ultraviolet detector, the effect of column temperature module, usually leads to a regular rise and fall of the baseline; one of the ways to deal with the heat exchanger before entering the detector, but the heat exchanger is something, it seems that it has not been used. 2. mobile phase inhomogeneity This cause of baseline drift is usually irregular, unlike the former effect of the mobile phase contamination or inhomogeneity will lead to a rise in the baseline.
2. Uneven mobile phase
This cause of baseline drift is usually irregular, unlike the previous column temperature effects, mobile phase contamination or inhomogeneity will lead to baseline elevation, the use of HPLC-grade solvents or high-purity salts or additives, and degassing of the mobile phase can solve the problem of mobile phase inhomogeneity caused by baseline drift.
3. Detector flow cell contamination or bubble detector flow cell contamination
Solution: Use a polar solvent (such as methanol) to flush the detection cell, if necessary, with a concentration of 1N dilute nitric acid for flushing, especially need to be reminded that the use of dilute nitric acid for flushing do not connect the PEEK connector, and do not use hydrochloric acid for flushing.
4. Excessive tightening of the detector outlet line.
This can lead to too high a back pressure in the detection cell, leading to possible cracks in the detection cell, which can lead to an elevated baseline. If the detection cell is really damaged, you can only consider replacing the detection cell.
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5.Problems with mobile phase mixing or changes in flow rate
When this problem is encountered, special attention should be paid to the working condition of the infusion pump.
6. Inadequate column equilibration
Especially when changing the mobile phase, the guidelines suggest that the solution should be of medium polar strength and that the column should be rinsed prior to analysis, usually 10-20 times the volume of the column.
7. contamination of the mobile phase
Especially if high purity reagents are not used.
8. Strong retention properties of the sample substance
This leads to severe broadening of the peaks, which manifests itself as a lifting of the baseline Note the expression here, which manifests itself as a lifting of the baseline, is actually a strong retention of the component being measured, where the baseline drift is actually a slow elution of the detected component.
9. Detector setting error