Why did the column break down after only three months of use?
The sample is so dirty! The mobile phase is so harsh! The HPLC column is especially prone to breakage. What to do!
I’ve already used in-line filters, and the pressure hasn’t increased, but the column breaks down fast. What should I do?
You need a guard column for your HPLC column!
About the guard column, usually, people worry about it.
How exactly should I choose a hplc guard column?
What do I need to pay attention to when using them?
Does it work that amazingly?
Today, we are going to tell you about them one by one.
The role of the hplc guard column
In the process of high-performance liquid chromatography, the column will be contaminated by the sample and the chromatographic system, leading to poor durability and shortening the column’s life.
The contamination from the chromatographic system mainly refers to.
1, solid particles generated by the wear and tear of the components in the HPLC instrument system.
2. Solid particles left by incomplete filtration of the mobile phase system.
Contamination from the sample mainly refers to
1, incompletely dissolved samples or completely dissolved samples into the chromatographic system.
2, due to the difference in solubility of the sample solvent and mobile phase solvent for sample dissolution, precipitation contamination of the system exists.
Especially for detecting traditional Chinese medicine, natural products, synthetic intermediates, and biological drugs, the contamination of chromatographic columns can be more serious due to the complexity of the matrix.
The contamination will lead to chromatographic system pressure increase, column collapse, packing discoloration, etc., which brings various effects such as high detection cost and inaccurate test results.
HPLC guard columns are important chromatographic consumables in liquid chromatography analysis. Using guard columns can greatly reduce the degree of contamination of analytical columns and prolong the service life of analytical columns.
The guard column is located between the injector and the analytical column and serves two main purposes.
1. retention of insoluble particles
2. adsorption of impurities from the sample matrix
How to choose a guard column
1, the packing of the guard and analytical columns to maintain the same! The packing brand is the same to ensure 100% selectivity consistency.
2, the specifications of the guard column to match with the analytical column! The packing particle size is the same, and the inner diameter of the guard column is similar to the inner diameter of the analytical column.
3, the guard column should be filled with good enough column efficiency for fine separation!
4, for fine separation or small inner diameter column separation, the dead connection volume of the protection column should be as small as possible.
5, if it is used for the UHPLC column, also consider the pressure resistance of the guard column.
The guard column is not ideal and will lead to peak diffusion separation degradation, which is not conducive to fine separation.
For the ideal guard column, even if the analytical column is short, such as 4.6 × 100mm, the installation of the guard column has not caused a decrease in separation and peak height.
How to use the guard column
1. Dedicated column. Avoid the guard column from becoming a source of cross-contamination of different items.
2, timely replacement of the guard column. When the peak theoretical column plate number drops 15%, column pressure rises 15%, or the key separation drops 15%, it should be a timely replacement of the direct connect guard column.
3, inadvertent strong contamination, you can remove the analytical column and separate rinse the guard column can make the contaminants faster from the guard column out.
Precautions for using the guard column
1, stand-alone guard column and analytical column connection, connecting pipeline as short as possible, and interface cut smooth, minimize the dead volume to reduce the effect of column outreach.
2, the ferrule type guard column is generally not marked liquid flow direction. The use of the best self-marked. Following the marked direction to use, the impurities trapped the contamination analysis column to avoid using the positive and negative directions.
3, the direct filling of the short column type guard column, when there is a column pressure rise or peak shape deterioration, can not be connected to the analytical column for reverse cleaning; the cleaning solvent can be referred to as the analytical column cleaning solvent.
4, ferrule type guard column, column core replacement, pay attention to the core and column sleeve whether there is a directional match, while not easy to screw too tight to prevent slippery wire.
5, the guard column or column core is generally not recommended for ultrasonic cleaning because of the possible impact on the packing surface modification.
6, the same guard column with a different analytical column, each time before use, the guard column should be cleaned and mobile phase equilibrium guard column for some time, and then connected to the analytical column use.
Post time: Mar-16-2023