Abstract: Gas chromatography is widely used in petroleum, chemical industry, biochemistry, medicine and health, food industry, and environmental protection. In addition to quantitative and qualitative analysis, it can also determine the physical and chemical constants such as the partition coefficient, activity coefficient, molecular weight, and specific surface area of ​​the sample on the stationary phase. An instrument that analyzes and tests the components of a gas mixture. This article mainly wants to tell you about some maintenance and maintenance of chromatograph in daily use.
(1) Column aging The new column or long-term unused column needs to be aged to remove volatile contaminants. Method: one end of the column is connected to the sample injector, the end connected with the detector is removed, the detector inlet is covered with a screw cap, the carrier gas is introduced, the furnace temperature is set to 100° C. for about 1 hour, and then the temperature is gradually increased to more than The temperature is about 25°C (do not exceed the maximum temperature limit of the column) and keep for 12-24 hours. The capillary column time can be shorter.
(2) Replacement of sample changer The service life of the septum depends on the number of uses and the quality of the needle. The general rule is to change the septum every day.
(3) Injector liner, liner tube, and detector nozzles should be cleaned with a suitable solvent.
(4) When the TCD detector is on, the filament will be permanently damaged if the airflow is not turned on or interrupted. The detector must be turned off whenever the adjustment affects the airflow through the detector.
(5) Hydrogen-powered detectors (FID, FPD, NPD). Once the hydrogen gas is connected to the instrument, the inlet connection must always be connected to a column or a cap. Otherwise, hydrogen will flow into the heating chamber and cause an explosion. .
(6) When using FID, FPD, NPD, the detector temperature must be higher than 100°C to avoid accumulation of water.
(7) The exhaust gas from the ECD detector must be vented outdoors to prevent contamination of the laboratory with radioactive active materials. Users with ECD must perform a radioactive leak check every 6 months.
(8) The gas to be used must be filtered through a purifier (containing discoloration silica gel, molecular sieves, etc.) to remove impurities such as moisture and oxygen.
(9) The detector temperature should be above the column temperature to prevent the sample or lost fixed solution from condensing in the detector.
(10) After each test is completed, clean the column with a few needles of solvent.
Liquid chromatograph maintenance (1) Leak detection at least once a day.
(2) When the pump is working under pressure, its parts must not be dismantled (unless an experienced maintenance person is performing troubleshooting).
(3) When preparing two or more eluents, it must be degassed before use to ensure that no bubbles form in the mobile phase system.
(4) Regularly check the lubrication of the pump and use only the lubricant specified in the instructions of the instrument.
(5) Regularly check detector noise, drift, and periodically perform detector calibration.
(6) High-performance liquid chromatography dedicated reagents for mobile phases are used unless it is proven that other grades of solvents are available.
(7) When replacing the solvent, be sure to flush the system. If the two solvents are incompatible with each other, they should be washed with a solvent that is compatible with both solvents, and then rinsed with a new solvent.
(8) The column cannot be dismantled at any time, so as to avoid loss of efficiency and to abandon the column.
Maintenance and Maintenance of Commonly Used Chromatography Analyzers The main fixed assets of physical and chemical analysis laboratories are large-scale analytical instruments. The following is the starting point for maintenance and maintenance, and talk about the sustainable operation guarantee of analytical instruments.
Large analytical instruments often give people a "delicious" feeling, and the cost of maintenance after a failure is usually astonishing. In fact, if used properly and well-kept, it can and should work for quite a long time. For example, we have here introduced a Shimadzu GC-9A in 1984. It has been used in the first-line work for 20 years.
It is not difficult to learn how to use analytical instruments. It is difficult to do it well and accurately. However, what is really difficult is how to ensure that it will continue to function normally for a long time.
We should not think that the instrument should be maintained when there is a fault in the instrument. We must not only do it regularly and purposefully, but also establish a concept: An important role of maintenance and maintenance is to guarantee a good detection status and ensure that Accurate test data.
Factors that affect the sustainable operation of analytical instruments include: 1. The replacement of consumable parts is not timely, 2. The use of hardware is not scientific, 3. The instrument itself is selected and improperly configured.
Various analytical instruments vary greatly in structure, function, and application, but there are certain commonalities in the problems that often arise and the direction of maintenance. This commonality is: "There are few problems in the fixed parts of the instrument itself, and it is easy for the user to contact the place where the user often touches."
(1) Column aging The new column or long-term unused column needs to be aged to remove volatile contaminants. Method: one end of the column is connected to the sample injector, the end connected with the detector is removed, the detector inlet is covered with a screw cap, the carrier gas is introduced, the furnace temperature is set to 100° C. for about 1 hour, and then the temperature is gradually increased to more than The temperature is about 25°C (do not exceed the maximum temperature limit of the column) and keep for 12-24 hours. The capillary column time can be shorter.
(2) Replacement of sample changer The service life of the septum depends on the number of uses and the quality of the needle. The general rule is to change the septum every day.
(3) Injector liner, liner tube, and detector nozzles should be cleaned with a suitable solvent.
(4) When the TCD detector is on, the filament will be permanently damaged if the airflow is not turned on or interrupted. The detector must be turned off whenever the adjustment affects the airflow through the detector.
(5) Hydrogen-powered detectors (FID, FPD, NPD). Once the hydrogen gas is connected to the instrument, the inlet connection must always be connected to a column or a cap. Otherwise, hydrogen will flow into the heating chamber and cause an explosion. .
(6) When using FID, FPD, NPD, the detector temperature must be higher than 100°C to avoid accumulation of water.
(7) The exhaust gas from the ECD detector must be vented outdoors to prevent contamination of the laboratory with radioactive active materials. Users with ECD must perform a radioactive leak check every 6 months.
(8) The gas to be used must be filtered through a purifier (containing discoloration silica gel, molecular sieves, etc.) to remove impurities such as moisture and oxygen.
(9) The detector temperature should be above the column temperature to prevent the sample or lost fixed solution from condensing in the detector.
(10) After each test is completed, clean the column with a few needles of solvent.
Liquid chromatograph maintenance (1) Leak detection at least once a day.
(2) When the pump is working under pressure, its parts must not be dismantled (unless an experienced maintenance person is performing troubleshooting).
(3) When preparing two or more eluents, it must be degassed before use to ensure that no bubbles form in the mobile phase system.
(4) Regularly check the lubrication of the pump and use only the lubricant specified in the instructions of the instrument.
(5) Regularly check detector noise, drift, and periodically perform detector calibration.
(6) High-performance liquid chromatography dedicated reagents for mobile phases are used unless it is proven that other grades of solvents are available.
(7) When replacing the solvent, be sure to flush the system. If the two solvents are incompatible with each other, they should be washed with a solvent that is compatible with both solvents, and then rinsed with a new solvent.
(8) The column cannot be dismantled at any time, so as to avoid loss of efficiency and to abandon the column.
Maintenance and Maintenance of Commonly Used Chromatography Analyzers The main fixed assets of physical and chemical analysis laboratories are large-scale analytical instruments. The following is the starting point for maintenance and maintenance, and talk about the sustainable operation guarantee of analytical instruments.
Large analytical instruments often give people a "delicious" feeling, and the cost of maintenance after a failure is usually astonishing. In fact, if used properly and well-kept, it can and should work for quite a long time. For example, we have here introduced a Shimadzu GC-9A in 1984. It has been used in the first-line work for 20 years.
It is not difficult to learn how to use analytical instruments. It is difficult to do it well and accurately. However, what is really difficult is how to ensure that it will continue to function normally for a long time.
We should not think that the instrument should be maintained when there is a fault in the instrument. We must not only do it regularly and purposefully, but also establish a concept: An important role of maintenance and maintenance is to guarantee a good detection status and ensure that Accurate test data.
Factors that affect the sustainable operation of analytical instruments include: 1. The replacement of consumable parts is not timely, 2. The use of hardware is not scientific, 3. The instrument itself is selected and improperly configured.
Various analytical instruments vary greatly in structure, function, and application, but there are certain commonalities in the problems that often arise and the direction of maintenance. This commonality is: "There are few problems in the fixed parts of the instrument itself, and it is easy for the user to contact the place where the user often touches."
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