change retention time with Gas Saver Time

Hi, 

Are you running split or splitless inlet conditions?  What is your total inlet flow at the time of injection?   Have you tried to run the split vent trap diagnostic to see if you have some restriction in the line?

Hi Dear,
my mode is split and its flow 200ml/min.
total flow is 205 ml/min.
how i can run this diagnosis ?

Yes,sir the gas saver is still 20ml/min after 2 min and when change the time to 10 min,the RT is changed like I mentioned before.

Yes, I use ramped flow in column at 2ml/min for 1.2 min then ramped 10ml/min per min till reache 4ml/min.

I was trying to use constant column flow and the issue persist.

Thanks for clarifying.  Of note, at the time your Gas Saver is enabled (2min), you have just finished a ramped flow increase, so your column flow at that point is 4mL/min, not 2.  The diagnostic trace will tell you when the system is stable at the new flow.  I would recommend waiting until that time before you turn on gas saver, like 2.5 or 3 minutes.  Alternatively, is there a chromatographic reason why you cannot simply start your run at 4 mL/min?   That would simplify the inlet conditions - at least for troubleshooting. 

A few other things I want to make sure I'm understanding correctly.  Under a 2min Gas Saver, your RT is around 4.7min.  When you delay the Gas Saver, your RT is later, but still elutes before the time you enabled Gas saver (RT of 7.9 min with Gas Saver enabled at 10 or 15 minutes).  This indicates that Gas Saver isn't creating the problem, but is masking it.  If you turn Gas Saver off completely, when does your MeOH peak elute? 

I will try to turn off gas saver and kindly allow me tell you what's the result.

Of course!  I look forward to hearing your results.  I think we are getting somewhere

Hi Abbey,
I did some trials as the following :
 gas saver is on ( 20 ml/min after 2 min ) and column constant flow at 4ml/min
- the RT for methanol is 4.56 min.
gas saver is off and column constant flow at 4 ml/min.
- the RT for methanol is 7.610 min.
gas saver is off and column constant flow at 5ml/min
- the RT for methanol is 5.626 min.
 gas saver is off and column constant flow at 7ml/min
-the RT for methanol is 3.679 min.
Since this issue is appeared, i observed the response is doubled ( before issue the response of methanol is around 5000 but when this issue is appeared the response of methanol become around 16000 !)

Hi Abbey,
I did some trials as the following :
 gas saver is on ( 20 ml/min after 2 min ) and column constant flow at 4ml/min
- the RT for methanol is 4.56 min.
gas saver is off and column constant flow at 4 ml/min.
- the RT for methanol is 7.610 min.
gas saver is off and column constant flow at 5ml/min
- the RT for methanol is 5.626 min.
 gas saver is off and column constant flow at 7ml/min
-the RT for methanol is 3.679 min.
Since this issue is appeared, i observed the response is doubled ( before issue the response of methanol is around 5000 but when this issue is appeared the response of methanol become around 16000 !)