**Using Capillary Columns: Installing the GC Column**

Use of Capillary Columns: Installing a GC Column • Remove the column of the required length from the holders for connection to the GC inlet and detector. • Pass the inlet assembly nut and ferrule through the column inlet end, and cut approximately 1 cm from the column end using a fine capillary cutter, ceramic tube cutter (Figure 1.) or another specialized cutter. The cut surface must be at 90°. The condition of the column cut surface on the inlet side of the instrument significantly affects analysis results and requires attention. For this reason, it is recommended to inspect the cut surface with a magnifying glass after cutting. Unless specifically stated otherwise, the inlet and outlet sections of the column are not specified. To obtain stable analysis results, it is recommended to predetermine the inlet and outlet sides. • Check the length to be placed in the injection port by referring to your GC instrument user manual. • Adjust the carrier gas pressure (flow rate) and check that gas flows without leakage. Set the column linear velocity to approximately 30 cm/s or adjust the column inlet pressure by referring to the table below. Inlet pressure varies depending on GC type, carrier gas type and other factors.

Relationship Between Column Size and Inlet Pressure

Note: The above assumptions use He as carrier gas and 40°C as initial oven temperature. We recommend the Leak Detector LD239 (Catalog No: 2702-19340) for checking helium gas leaks. In high-sensitivity analyses, soap solution or other liquids should not be used for leak testing, as they can contaminate the entire system and damage the column.

Column Conditioning

• Ensure carrier gas is flowing. If necessary, use gas purification tubes to remove moisture, oxygen and organic matter. • Remove the column only from the detector side (except for H2 gas applications). • Purge for at least 20 minutes at room temperature with carrier gas flow. Increasing temperature after insufficient purging can impair column performance. • Increase temperature from room temperature at a rate of 5°C/min to 10°C/min. Condition the column at a temperature up to 10°C below the maximum analysis temperature for approximately 1–2 hours. However, if the temperature exceeds the maximum column operating temperature, please condition at the maximum column temperature.

Silicone-Based Liquid Phases

Apply carrier gas at room temperature for at least 20 minutes. Increase temperature from 40°C to the maximum conditioning temperature at 10°C/min and hold for 2 hours.

WAX-Based Liquid Phases

Apply carrier gas at room temperature for at least 20 minutes. Increase temperature from 40°C to 100°C at 5°C/min and hold for 30 minutes. Then increase temperature to the column's maximum conditioning temperature at 5°C/min and hold for 2 hours. After completing conditioning, connect the column to the detector side. Temperature will return to the initial analysis temperature, but the baseline will decrease slowly over the next 10 minutes. Wait for the baseline to stabilize before starting analysis.

Column Storage

After purging the column with carrier gas, close both ends of the column with fused silica caps or similar. The column should be stored in its packaging box, away from direct sunlight. To ensure analytical accuracy, column performance should be checked periodically. Resolution status can be verified by comparing the capillary column test sample (sold separately) resolution with the factory resolution. Measuring the column bleed level periodically at the beginning of use is also recommended to detect column deterioration. If the liquid phase deteriorates due to heat or oxidation, the column bleed level will increase and the baseline will rise.

Information

Column bleed level should be measured at 40°C (wait 1 minute) and then increased gradually at 10°C/min to each column's maximum operating temperature (wait 10 minutes).   Ezgi Özler - Sales Manager Assistant – Pharmaceuticals Ant Teknik Doğan Özdemir - Senior Sales Specialist – Pharmaceuticals Ant Teknik