Electro spray needle won't stop spitting please help

[neil777]

Hi
I am using bruker mass specs and have done for ages. Unlike thermo instruments the metal electro spray emitter itself does not carry a charge, the charge is on the source plate itself. Ideally one aims for a constant 'jet' stream that flies over the hole. Lately the liquid nano flow is constantly spitting and everything I try does not help. I've tried changing the emitter and cleaning everything. I really need a constant stable spray otherwise the sensitivity is all over the place
Any advice is hugely appreciated

[Infinity]

I would purge pumps, try to tighten all the connections, make sure that degasser works...

[proteomicsadvice]

I have had this same problem with agilent instruments (which use the voltage on the plate rather than the needle) and has made me dislike their instruments. Can you get stable spray from direct infusion? If so then it is the LC like Infinity suggest. Whose emitters do you use? There are various types of coatings for the needle that may help (Try new objective). You also may have cleaned the interface too much (rubbed off some of the finish/surface) and need to look for a new capillary / inlet covering (depending on the age of the instrument). Let me know if the direct infusion works or not. Since you have used an instrument for so long, I am not going to suggest playing with the voltages (as a first step) because I believe you know to try those things.