ICP-MS 7700 Tune not passing in Helium gas mode (%RSD is little bit high)

Question

I am running ICP-MS 7700 with mass hunter, for tune with Helium gas mode ON, my %RSD is little bit high. can anybody help me to make it pass? what will be the troubleshoots? I cleaned cones, changed tubings for perilistic pumps still no improvement.

ktpandian · Answer

Hi SSaiyad, 
 1. In helium mode. If He mass count improved with Zero helium flow. then please check following. 
 
 Leak in Helium gas line. Leak check procedure: Close He cylinder valve and set flow to 10ml/min. after overnight evacuation flow should come down to 1ml/min. 
 Replace purifiers. moisture and hydrocarbon in Helium impact sensitivity. 
 Helium purity is low. replace cylinder. 
 
 2. If above mentioned points are good i suggest octupole replacement.