Gas chromatograph operation guide:11 Practical Suggestions

1.Operate according to the instructions in the instrument manual:

When inspecting the instrument, not only should all components be counted for completeness, but also the instrument manual should be checked for completeness,And keep these materials properly. Before operating the instrument independently, be sure to carefully read the relevant instructions,And strictly follow the procedures for operation. This is a prerequisite for good instrument analysis, and once there is a problem with the instrument, it is also easy to negotiate with the manufacturer.

2.Prepare a chromatographic column test standard sample:

The performance of the chromatographic column is the key to ensuring the analysis results. The newly purchased chromatographic column should first be evaluated for its performance using test samples. If the test conditions provided by the chromatographic column manufacturer do not meet the requirements, a return or exchange can be requested. More importantly, the performance of the chromatographic column will change during subsequent use. When there are problems with the analysis results, a test standard can be used to test the chromatographic column and compare the results with the previous test results. This helps determine whether the problem lies in the chromatographic column, so that appropriate measures can be taken to eliminate the fault.

3.Use carrier gas with the required purity:

The carrier gas must be of high purity to avoid interfering with the analysis and contaminating the chromatographic column or detector. You should know that the price of a chromatographic column is the price of a bottle of high-purity nitrogen or hydrogen20More than double. If ordinary gas is used as a carrier gas to save money, it may be because watermelon is lost and sesame is picked. It is best to use high-purity auxiliary gases for detectors. Although ordinary gas can be used when sensitivity requirements are not high, the cost may be contamination of the detector. Replace the chromatographic column gasket in a timely manner.

4.Timely replace the graphite sealing gasket:

Is the graphite gasket leakingGCOne of the most common malfunctions. Never reuse the same sealing gasket on different columns. Even if the same column is removed and reinstalled, it is best to replace the sealing gasket with a new one to ensure higher work efficiency. If gas leakage is found after installing the chromatography column and the sealing gasket is replaced, it will take more time. Even if the old gasket can still be used, it needs to be tightened more than before. If it is not done properly, the capillary chromatography column will be broken.

5.Regularly replace the packing of the gas purifier:

Color changing silicone can be judged based on its color change, but purifiers such as molecular sieves that adsorb organic matter are difficult to judge with the naked eye. So it needs to be replaced regularly, preferably3Replace once a month. If silica gel and molecular sieve are installed together, the molecular sieve should also be replaced when replacing the silica gel.

6.Use reliable gas pressure reducers:

New pressure reducers must be tested for leaks during use, and regular leak checks should also be conducted during long-term use. This is a good habit for discovering problems. If you don't pay attention to this issue, it may result in gas waste or safety problems. It's too late to regret.

7.Regularly replace the injection liner:

Is the injection port gasket leakingGCOne of the common faults. In addition, the aging and degradation of the pad can also interfere with the analysis. For example, debris falling into the vaporization chamber may also cause ghost peaks. As for how often to change the pad, it depends on the properties of the sample being analyzed and the analysis conditions. Conventional laboratories usually replace one injection pad per day. Anyway, the continuous use time of a pad should not exceed one week.

8.Timely clean the syringe:

Keeping the syringe clean can avoid interference from sample memory effects. When replacing the sample, it should be cleaned, and when injecting the same sample multiple times, the syringe should also be cleaned with the sample itself. When a syringe is temporarily not in use(For example, after work)Cleaning is even more important, otherwise residual samples may stick the needle core firmly and cause the syringe to be scrapped. Users using automatic samplers should also pay attention to this issue, preferably by regularly replacing and cleaning the syringe.

9.Regularly inspect and clean the injection liner:

After long-term use of the instrument, there will be tar like substances in the injection liner, which are caused by non-volatile components in the sample. In addition, there will also be the accumulation of particulate matter(Spacer debris, solid material in the sample)All of these will interfere with the normal progress of analysis. Therefore, regular inspections and timely cleaning are necessary. Note that filling some silica glass wool treated with silane in the liner can improve the vaporization efficiency of the sample and prevent debris from entering the chromatographic column and causing blockage.

10.Replacing parts should be done one by one:

When repairing instruments, do not replace multiple components at once, as it may cause errors in determining the cause of the malfunction. One should be replaced at a time, and another should be replaced after testing. This may make it easier to accurately determine the cause of the malfunction,Meanwhile, avoid unnecessary expenses.

11.Keep records of instrument usage and analysis, and regularly archive them:

This is the record of the instrument, which should be recorded daily, including the operator, analyzed samples and conditions, instrument working status, etc,Once there is a problem with the instrument, this is important information for finding the cause.