Chromatography Forum

hi
I have an hp 6890 series, front inlet s/sl temp 350ºc, pressure 20.9, splt ratio 36.4 split flow 78.6 ,total flow 83.2 gas saver off, oven temp 35ºc.
My inlet temp did'nt reached setpoint, it take a long timethis happened when a changed column . The new one is varian cp-9010, vf-1ms EZ GUARD Tmax 350ºc. we increase temp of oven 45º and the inlet temp reach but resolution was bad. we work with hydrocarbons, crude oils.
Can you help please!
Bst Rgds
FFD

I cannot think of any way that changing a column could cause an inlet not to reach its temperature setpoint as long as there is nothing else wrong, and so there is probably something wrong with the inlet heater cartridge, the temperature sensor or the electronics.

However, if there is a leak (which could arise from a column change) the GC shuts down the flow and the temperature of the inlet.

Column installation leaks are easier to find and fix than broken inlet heaters, so you first step needs to be to check for leaks and to make sure that the GC reaches its pressure setpoint.

Peter

Hello
a similar problem has occured in my lab with 6890, but with ECD: when the oven was held at low temp the ecd don't stabilize at his setpoint.
I think your problem is in the insulator of inlet: take a look at cup below injectr into the oven. Add some insulating material if you can and check the position of cup.
Good luck

Francisco,

If you changed the column and you did not put the injector insulation can back on, considering the temp you want to hold the injector, it is highly likely that you have too much gradient and the injector cannot reach temp.

Best regards.