Thermo Fisher ColumnIt has digital communication function, software and instrument linkage control function, and can be directly clicked with the mouse to complete various tests. The detector transmission adopts a three-level gear reduction structure, which ensures the seismic performance of the instrument and prevents vibration during transportation and use; Adopting a high brightness OLED display screen, with beautiful visual effects and ultra-high quality stability. Built in deuterium lamp and deuterium lamp, the built-in components can achieve wavelength conversion from 190-850nm without replacement; The instrument uses an original deuterium lamp, which can be manually turned on/off. When replacing the deuterium lamp, there is no need to adjust the optical axis, making maintenance simple and the deuterium lamp has a long service life. The optical system adopts priority concave grating devices, combined with precision positioning structures and heat dissipation technology, to achieve high wavelength accuracy, small offset, and short stability time. The optical system and digital filtering improve the sensitivity, accuracy, and repeatability of the instrument, ensuring its stability and reliability. Humanized and portable software interface, human-machine engineering operating platform and buttons, convenient and fast operation; Sample and reference energy display facilitate fault diagnosis and troubleshooting; The instrument has internal safety alarm and automatic fault diagnosis functions, and maintenance is fast. It has wavelength automatic correction function, automatic zero adjustment, and multi range output selection to meet the analysis needs of various concentrations.

In the use of Thermo Fisher columns, we will find that many laboratories face the problem of frequent column damage. We need to understand from which aspects the damage to the chromatographic column comes:

Wear of pump head sealing ring; Wear of the sealing ring of the injection valve rotor; The precipitated buffer salt; Complex and easily adsorbable matrices in the sample, etc; In fact, the problem of increased back pressure in chromatography columns caused by most particle blockage during the working process is reflected in column head blockage. The easy adsorption mechanism of the sample may also interact with the free silanol groups on the surface of the silica gel at the front end of the column, leading to an increase in the back pressure of the chromatographic column. But this situation will improve in lower pH systems, as lower pH systems will reduce the dissociation of silanol groups on the surface of silica gel.

Preventive measures:

1. Add an online filter to the liquid phase system

The internal particle gap of online filters is generally 0.5 microns, and UHPLC will choose online filters with a gap of 0.2 microns. The size of this gap is similar or slightly smaller than the size of the filter screen of the column head. So, online filters can effectively block particles from the sample, pump head gasket, and rotor gasket of the automatic sampler to prevent clogging of the column head filter plate. Attention: However, for liquid phase systems with very low dead volume, the addition of online filters may lead to an increase in the system's dead volume and a more severe peak broadening issue. For most liquid phase systems, the chromatogram will not undergo significant changes.

2. Use a protective column at the front end of the column

There are many types of protective columns, including universal, integrated, and sleeve type, but it is actually a small column of 10-20mm that is fixed to the analysis column. Because it has the same internal packing as the analytical column, the protective column can not only block particulate matter, but also block easily adsorbed sample matrix components. Attention: Due to the possibility of a large amount of strongly retained components in the protective column, please remove the protective column when cleaning the system with strong solvents to prevent these strongly retained components from being washed into the analytical column. If the protective column experiences adsorption saturation, it may also affect the separation efficiency.

3. Purification treatment of samples

Some liquid phase analysis methods do not clearly indicate the purification of the sample, but I hope everyone can consider the purification of the sample when conducting analysis. The commonly used solution is to filter the sample. In practical work,Thermo Fisher ColumnThe storage also affects the service life of the column. So for the storage of chromatographic columns, there are also the following suggestions:

4. Precautions for use:

To avoid organic solvents and bubbles in the pipeline entering the chromatographic column, first flush the whole chromatographic system with water, and then connect it to the gel column.

Do not allow organic solvents to enter the column, otherwise it will dehydrate the packing and cause damage to the column bed. Start the pump at a low flow rate and do not quickly increase the flow rate to prevent rapid pressure rise and damage to the column bed. The flow rate of a 15mm column should not exceed 3ml/min.

After each use, rinse with distilled water and replace the salt containing mobile phase completely. If not in use for a long time, please store according to the storage method.

5、 保存方法：

Rinse the gel column with distilled water and fill it with 0.02% -0.05% sodium azide aqueous solution for storage, or seal the column with trichlorobutanol phenyl mercuric salt and store it at low temperature (about 5 ℃) in the refrigerator.

When reusing, rinse off the protective solution with distilled water before use.

If you want to use it again the next day, you need to remove it from the systemThermo Fisher ColumnStore in a refrigerator at 4-8 degrees Celsius after sealing.