Chromatography Forum

I have the ability to set up cryo cooling for my agilent 7890B GCTQ with MMI 100 PSi inlet with liquid nitrogen. Currently my inlet is set to 60C for the start of the run and ends at 310C. Does anyone know about the rate of cooling, for my inlet, also can this set up assist in cooling the oven as well.

Oven cooling is separate.
I don't know about the newer models but on the old 6890s pressures over ~60psi were too high for the inlet cooling to work properly.
I have to keep my LN2 supply at 55psi.

I used the MMI with CO2 cooling and it will cool the inlet from 300c to ambient in just a couple minutes, the LN2 will probably be even faster.

The cryo on the inlet will cool the oven a little, but not super fast. If you leave the insulator cup off the bottom of the inlet the cryo liquid will spray down into the oven, but with the high speed fans in the 7890s now, they cool so fast you won't see much difference.

Steve I believe the 100 being referred to is the maximum carrier pressure, the new 7890 MMI inlets are rated at 100psi carrier pressure which is nice when using 0.18 or smaller columns.

I have even used my MMI with just compressed air for the cooling and they will cool to ambient quite fast, you just can't go sub-ambient, but if you are having the inlet temperature track the oven temperature it works great, and it is nice when you want to do maintenance as you don't have to wait 20-30 minutes for the inlet to cool