Your column may suffer from short working life, which not only causes rising costs, but also impacts the experimental results. Today, we invite Welch engineers to answer questions about how to prolong the column life.
Why different brands of columns used in the same detection almost fail to work after 100 injections?
1) The most likely reason is that the sample components are adsorbed at the front of the column. It may precipitate due to the low solubility of the sample in the mobile phase, strong adsorption or a weak and unpredictable chemical reaction between the sample itself and the surface of packing materials. If pH of the sample solution is near the maximum tolerance of column while injection volume is large(inner diameter is 4.6 mm and the injection volume of sample is more than 50 ul), it will have a greater impact on the packing materials of the column head, which is usually accompanied by increased column pressure.
Solution: select the appropriate sample pretreatment technique to remove substances with strong retention. Try to use guard columns with the same bonded method and packing material as the analytical column. If you use guard columns with different brands of packing materials or packing techniques, the best effect may not be achieved in the separation capacity and protection of the analytical column. Avoid using guard column with larger particle size, because guard column with larger particle size or poor packing will decrease the separation capacity by its peak broadening effect.
2) Shedding and denaturation of bonded phase. Diverse chromatographic conditions lead to shorter life of column, which can not be solved by the current chromatographic technology. In general, the bonded phase of small groups is more likely to be hydrolyzed and shed off. The higher the salt concentration in the mobile phase, the more likely it is to cause hydrolysis. In this case, the chromatographic conditions can only be redeveloped.
Why that brand’s column life is always long but this one is an exception?
Check whether the use frequency, flushing frequency, mobile phase replacement frequency, mobile phase, reagent brand, purity, etc. are the same as before. If there is replacement, it is normal to have a difference in column life. If they are the same as before, it is necessary to check whether this column suffered severe vibration, such as: accidentally fell, or severe vibration during transportational process, please contact with the manufacturer’s technical personnel.
Why does the first column of this brand have a long life as it is used for method development, and a short life as it is used for method verification?
The main reason for this situation is that you don’t do the project continuously when you develop the method in the early stage, but you change the mobile phase constantly. This means that the flushing frequency of the column is relatively high, and the cleanness of the replaced mobile phase is good. It is difficult to inject sample for multiple times, so sometimes we even do the project once a week, giving the illusion that the first column last longer. After the development of the method, the method is being verified. When the mobile phase is fixed, a large volume of mobile phase will be configured at one time. In this way, the mobile phase is prone to metamorphism and sometimes cannot be directly distinguished by the naked eye. Moreover, samples are injected overnight for many times continuously, so the column flushing is not very timely. These are the factors that may lead to shorter column life.
If you have any problem or require further information, please contact firstname.lastname@example.org.