What are the methods and ways to improve the column efficien

There are two ideas, one is experimental method, the other is chromatographic column.
Chromatographic column: after a long time of use, the column efficiency will decline naturally. If it is due to the aging problem, it needs to regenerate the chromatographic column. Wash with 10% methanol water, pure methanol, isopropanol, dichloromethane, isopropanol, pure methanol, and 10% methanol water in the order of each solvent for not less than 40 min.
There are usually pay attention to the use of chromatographic column after washing the column clean. Sometimes there are strong retention substances in the column, it can also be considered to recoil the column with pure methanol for 4-6 hours.
Experimental method: a lot of times, a mention of low column efficiency will think of chromatographic column is not good. In fact, the experimental method may not work. The column efficiency can be improved by adjusting pH value, adjusting solvent, using buffer salt and tailing agent. For example, the chromatographic peak of alkaline compounds will be tailed, which will be very ugly. If you change the chromatographic column of basic compounds, the column efficiency will be significantly improved.
1. The most effective way is to use the column well
2. The carrier gas is qualified, and the purification is good, which is good for the baseline background, and can also play a certain role in improving the column efficiency
3. If the column is fixed, the column should be aged frequently, which is beneficial to the improvement
4. The sample with damage to the column cannot be injected, such as strong acid, strong alkali, water, inorganic salt, etc.
5. Clean the column with organic solvent according to the standard method and carry out regeneration.
6. When the peak height is suitable, the injection should be as few as possible.
The column will not be damaged when the temperature rises under the protection of carrier gas. Otherwise, other oxidizing substances left in the column may damage the stationary phase at high temperature, which will reduce the column efficiency and is not conducive to sample detection.
Gas chromatography was compared with liquid chromatography
Because of the low relative analytical capacity and large molecular gap of carrier gas, gas chromatography has low viscosity, good fluidity and fast flow rate of components in the gas phase. Therefore, the column length can be increased to improve the column efficiency
This is why the gas chromatographic column is longer than the liquid chromatographic column.
Compared with packed column chromatography, capillary column gas chromatograph has an additional split / no split device and a tail gas path behind the column. In order to prevent the overload of capillary column (glass material), a small part of the sample in the gasification chamber can enter into the column through the split flow, and the rest will be vented. To protect the capillary column.
Tail blowing can reduce the "residence" time of the substance flowing out of the capillary column behind the column, so as to ensure the carrier gas flow and reduce the time for the sample to pass through the column, so as to improve the efficiency.
If the packed column is lengthened, the analysis time will be lengthened?
Under the same conditions, whether the length of packed column or capillary column is increased, the analysis time will be longer than before.
The increase of column length means that at the same flow rate, the time of passing through the column and arriving at the detector increases, so the retention time increases. Longer analysis time
In fact, for the same length, the packed column should have higher column efficiency because of its dense packing and more contact with the sample, but in fact, the capillary is much longer, generally 30-100 meters, and the packed column is generally 15 meters. Moreover, the capillary column is much thinner than the ordinary literal translation column, which leads to the higher column efficiency of capillary gas chromatography than the packed column.
What are the methods and ways to improve the column efficiency of gas chromatography_ There are two ideas: one is the experimental method, the other is the chromatographic column. Chromatographic column: the column efficiency will decline naturally after using for a long time. If it is due to the aging problem, the chromatographic column needs to be regenerated. The order of 10% methanol water, pure methanol, isopropanol, dichloromethane, isopropanol, pure methanol and 10% methanol water is used, Every solvent should be washed for no less than 40 min. in addition, the column should be washed clean after using. Sometimes there are strong retention substances in the column, so we can consider using pure methanol to backwash the column for 4-6 hours, For example, if you change the column of basic compound, the column efficiency will be improved obviously
Methods to improve the column efficiency of high performance liquid chromatography_ Methods to improve the column efficiency of liquid chromatography include: improving the column packing, changing the chromatographic conditions (temperature and flow rate), etc. the most important method is to improve the column itself. However, the manufacturer of this column must consider more, so I don't need to use so many tubes for QC. In addition, if the column efficiency decreases, some column efficiency can be recovered by changing it after storage for a period of time