1. If the peak monitoring window m/z28 strength than m/z18 strength greater than 2 there is gas leakage may, further judgment m/z28 strength and m/z69 strength ratio, less than 2 is not leak, if more than 2 have the possibility of leakage.
2. Confirm vacuum start time, usually vacuum start after 2 hours to reach a steady state, if the startup time less than 1 hour, nitrogen peak may be slightly higher.
3. Check the system whether there is false leak:
(1) if just replace cylinders, load trachea way into the air, in a period of time can be caused by nitrogen peak is higher, increase the split ratio, make the total flow increase to 500 ml/min, blowing after 10 minutes then to leak test.
(2) if just replace load trachea passing filter, in a period of time caused by nitrogen peak is higher, can increase the split ratio, make the total flow increase to 500 ml/min, blowing ten minutes then to leak test.
(3) if load trachea and installing a helium gas filter, the use of a period of time after filter will produce saturated and release nitrogen, cause peak when monitoring nitrogen peak slightly tall, recommend replacing new helium gas filter.
(4) the helium gas purity is not enough, impurity containing nitrogen, part in peak when monitoring nitrogen peak slightly high.
4. Through above judgment, if in the peak monitoring is air leakage, the most common leak could be:
(1) the chromatographic column on both ends of the nut is fastening, the new installation Vesple pressure ring, need heating to 200-250 ° C keep 10, 30 minutes, cooling retightened after can be completely sealed.
(2) check the injection port gasket is more than the number of use, injection port nut are tight.
(3) check the injection port liner type O sealing ring is damaged, injection port liner nuts are tight.
(4) if the vacuum chamber door seal on is stained with dust, also can cause the system leakage, please close vacuum after open the vacuum chamber door, remove the dust on the seal, restart the vacuum, leak test. If the peak monitoring window m/z28 strength than m/z18 strength greater than 2 there is gas leakage may, further judgment m/z28 strength and m/z69 strength ratio, less than 2 is not leak, if more than 2 have the possibility of leakage. If the peak monitoring window m/z28 strength than m/z18 strength greater than 2 there is gas leakage may, further judgment m/z28 strength and m/z69 strength ratio, less than 2 is not leak, if more than 2 have the possibility of leakage. If the peak monitoring window m/z28 strength than m/z18 strength greater than 2 there is gas leakage may, further judgment m/z28 strength and m/z69 strength ratio, less than 2 is not leak, if more than 2 have the possibility of leakage.strength greater than 2 there is gas leakage may, further judgment m/z28 strength and m/z69 strength ratio, less than 2 is not leak, if more than 2 have the possibility of leakage.