UPLC error message

[cliff]

I have been getting this error from an Acquity UPLC: "(sample pressure low (1.7), possibly no wash solvent or needle is damaged)". I matched the weak needle wash to the starting MP conditions and washed lines many times. However, when a sequence is submitted, maybe a dozen or so injections will be completed successfully, then the system stops with this error. Any ideas out there??

[Bull76]

Hi,

Usually indicates a leak. More often than not it is the Needle connection at the inject pod or the needle seal. Or it could be a leaking metering valve. Do a needle seal leak test and all the other SM diagnostic tests.

[Hollow]

I've had this error too, but normaly only on the first injections if the system was not used for some time.

What then helps for me, is to carry out some (2-3x) "wash needle" cylces with about 1000 µL volumes for both, strong an weak wash.
Maybe the error will show up in the first or second cylce, but once it passes the cycle, I've never had problems during a sequence.

[bmo37]

Hi,

Usually indicates a leak. More often than not it is the Needle connection at the inject pod or the needle seal. Or it could be a leaking metering valve. Do a needle seal leak test and all the other SM diagnostic tests.

Yep I've usually seen it be the needle wash port seal, we mostly hand tighten the needle wash tube when installing them and perform a needle characterization afterwards, sometimes they loosen up. Or like stated it can be a priming issue or leak somewhere else on the system. Another common occurrence I've been seeing lately is the sample syringe valve starts leaking out the bottom of the weep hole usually due to the solenoid valves getting stuck and over pressurizing the system, which causee it to leak at the weakest point.