Technical Information of Daicel Chiral Column
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Comprehensive Analysis: Daicel Chiral Column AD-H, Daicel Chiral OD-H, Daicel Chiral Column
1. What is the difference between CHIRALPAK AD-H column and CHIRALPAK AD?
The packing types of CHIRALPAK AD-H column and CHIRALPAK AD are the same, the surface is coated with amylose-tris (3,5-xylylcarbamate), and the chiral selectivity is basically the same. But the particle size of the filler is different, CHIRALPAK AD-H is 5 μm, CHIRALPAK AD is 10 μm. CHIRALPAK AD-H can replace CHIRALPAK AD and CHIRALPAK AD-H is more efficient.
2. The resolution of the isomers in the chiral column spectrum has decreased. What could be the reason and what should I do?
The reason for the decreased resolution may be that the chromatographic conditions outside the column have changed, or the damaged column efficiency has changed. First, check whether the external factors such as temperature and mobile phase composition have changed to reduce the resolution. If you exclude all external factors, it may be caused by the reduction of the efficiency of the analytical column itself. If the resolution drops sharply in a short time and the column pressure rises, there may be a strong polar solvent that damages the column; if the resolution decreases slowly over a long time, the column head may be contaminated or the column head collapses, and the guard column needs to be replaced or Replace the analytical column.
3. What should I do if the pressure of normal phase chiral chromatography column is high?
The reason for the high chiral column pressure may be that the content of alcohol in the mobile phase is too high, or there is a blockage in the liquid phase flow path, or the column head has sample precipitation, or the packing is compressed and the column head collapses. For different reasons, please take appropriate measures. If the alcohol content in the mobile phase is too high, you need to increase the temperature or reduce the flow rate. If there is a blockage in the liquid phase flow path, the blockage needs to be removed. If there is sample precipitation at the column head, you need to use the mobile phase to dissolve the sample and sample pretreatment to remove the components that are easily precipitated from the sample. If the packing is collapsed by the high-pressure compression column head, you need to purchase a new chiral column.
4. Will the column be damaged after the positive phase chiral column is filled with water?
Normal-phase chiral chromatographic columns AD-H, AS-H, OD-H, OJ-H will increase the column pressure once water enters, but as long as the column pressure does not exceed the upper limit of the column pressure, the column will not be damaged. Simply replace all the water with a low flow rate of absolute ethanol (0.1-0.2 ml / min), and then replace all the ethanol with a low flow rate of normal phase mobile phase (0.1-0.2 ml / min) to continue using the positive Phase chiral chromatography column.
5. How to clean and save the chiral column after use?
If a mixed mobile phase of n-hexane and alcohol is used for a normal phase chiral chromatography column, it is only necessary to rinse with a storage solution of n-hexane / isopropanol = 90/10 (v / v) for 30 min. If a mixed mobile phase of aqueous solution and acetonitrile is used in the reversed-phase chiral chromatography column, it only needs to be rinsed with water / acetonitrile = 70/30 (v / v) storage solution for 30 min.
6. What is the range of normal pressure chiral column pressure?
Normal-phase chiral chromatography columns AD-H, AS-H, OD-H, and OJ-H must not exceed 9.8 MPa, preferably 5 MPa. Therefore, it is recommended to set the protective pressure of the pump to 6 MPa on the liquid phase instrument during actual use. In this way, once the system pressure exceeds 6 MPa, the pump will automatically stop running to protect the chiral column from high-pressure damage.