On-line gas chromatograph has high sensitivity and can detect component contents of ppm and ppb. High selectivity can effectively separate components with very similar properties. The required sample volume is small, generally several milliliters for gas sample and several microliters or tens of microliters for liquid sample. It has a wide range of applications and can analyze low-content gas and liquid as well as high-content gas and liquid, may not be limited by the content of the components. We have listed several instruments "use coup", take a look:

　　1.On-line gas chromatographShould be strictly in the prescribed conditions of work, in some conditions do not meet the corresponding measures must be taken;

2. When FID is combined with a standard small-diameter capillary column, the capillary column can be inserted into the inner hole of the FID quartz nozzle, and the end surface of the column is 1-2mm lower than the nozzle opening, which is good, thus ensuring the column efficiency;

3. When using the gas chromatograph, be sure to check the status of the TCD bridge current switch on the lower right side of the computer control system frame. It should be in the correct position. For example, when using FID, the switch should be placed in the bridge current disconnection position. Otherwise, if you accidentally press the TCD bridge flow key during panel key operation, the TCD thermal conductivity element will be damaged;

4. The operation of the thermal conductivity detector must strictly abide by the operation principle of the thermal conductivity detector passing the carrier gas first and then the thermal conductivity constant current source. When the operation is restarted after long-term shutdown, the carrier gas should be supplied for more than 15 minutes, and then the detector should be energized to ensure that the thermal conductivity element is not oxidized or burned out;

5. When the plane six-way valve is used for gas injection, the sampling gas flow rate and pressure must be kept consistent every time to ensure the repeatability of the analysis. When the plane six-way valve rotates, it can only be placed at the two ends but not in the middle. The middle position will cause the carrier gas to be cut off, thus causing damage to the thermal conductivity element;

6. When shutting down the on-line gas chromatograph after use, it must be remembered that the bulkhead nut must be screwed on the outlet joint of the thermal conductivity cell to prevent oxygen in the outside air from returning to the chromatographic column and detector system after the carrier gas is cut off. It is to protect the chromatographic column and detector. After high temperature use, special attention must be paid to the temperature of the column box and detector below 70 ℃ before shutting down the gas source;

7. In order to ensure the baseline stability when FID is used under high sensitivity, trace CH (hydrocarbon) impurities in the gas should be removed from the gas. The stationary phase of the chromatographic column must be fully aged at a temperature slightly lower than the high service temperature, thus reducing the loss of the stationary liquid and the influence of the residual solvent in the stationary liquid on the baseline. When the vaporization chamber is used at high temperature, the silicone rubber pad of the sampler must be aged at high temperature and the diaphragm must be opened to clean the gas path;

8. Regular maintenance of on-line gas chromatograph can not only make the instrument work normally but also prolong the life of the instrument.