Column aging - Huaqiang Electronic Network

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Capillary column aging operation

Purpose of aging: The stationary phase of the GC column is usually distributed in the form of a coating on the inside of the column tube wall (capillary column) or the carrier surface (filled column) for a new one.

In gas chromatography columns, the combination of the outer stationary phase and the carrier tends to be weak, and it will slowly lose at high temperatures, causing baseline fluctuations and noise, in order to avoid this phenomenon,

It can be heated in advance at a higher temperature (generally the temperature tolerance of the column) to volatilize the weaker stationary phase, so that the latter analysis is not dried.

Disturb. In addition, the long-lasting GC column can be aged to remove residual contaminants from the column.

The column temperature is raised to a constant temperature, usually the upper temperature limit. In special cases, it can be heated to about 10-20 oC above the operating temperature, but it must not exceed

Pass the upper temperature limit of the column, which will damage the column, and do not set the temperature of the program too slow. After reaching the aging temperature, the baseline was recorded and observed. ratio

For example, the baseline is enlarged for easy observation. In the initial phase, the baseline should continue to rise and begin to decline 5-10 minutes after reaching the aging temperature and will last for 30-90 minutes. when

When a fixed value is reached, the baseline will stabilize. If the baseline is still not stable after 2-3 hours or there is no obvious downward trend after 15-20 minutes, then there is

The system can be leaky or contaminated. In such a situation, immediately lower the column temperature to below 40oC, check the system as soon as possible and resolve the related problems. If still succeed

Continued aging not only damages the column, but also does not always achieve a normal stable baseline. In addition, the aging time should not be too long, otherwise it will reduce the life of the column.

Life.

In general, columns coated with a polar stationary phase and a thicker coating have a longer aging time, while a weakly polar stationary phase and a thinner coated column require less time. Color

The aging method of the column is different. For the specific steps, please refer to the operating instructions of the column. If the column is aged without being connected to the detector, then after aging,

The end of the column may have been destroyed. The 10-20 cm portion of the end of the column was first cut off and the column was attached to the detector.

Temperature limit is the range of application temperatures at which the column can be used normally. If the operating temperature is below the lower temperature limit of the column, the separation and peak shape will not be ideal.

But this does not harm the column itself. The upper temperature limit usually has two values. The lower value is the constant temperature limit. At this temperature, the column can be used normally, and

There is no specific duration limit. The higher value is the temperature rise limit of the programmed temperature. The duration of this temperature is usually no more than ten minutes. Above the upper temperature limit

Reduce column life.