i am (was) in the process of leak checking a shimadzu QP2010-MS and now the pressure is building up the inlet pressure. Any ideas on the cause of this? I did a system check and got the warning that shutting off the flow with MS vacuum on may damage the column (could it have collapsed the column?) We normally have about 120kPa on the inlet pressure and a total flow rate of 10ml/min, but now it is spiking up above 300kPA. Thanks for responses. I took the machine off-line for fear of damaging the ion source. any help is greatly appreciated.