High RSD - Repeated corona pin instability with APGC on the Xevo TQ-XS - WKB117656

SYMPTOMS

• Corona current bounces around set point
• High RSD on Int Stds as beam drops in and out.
• Pin was cleaned and replaced
• Ceramics are clean 

ENVIRONMENT

• APGC
• Xevo TQ-XS

CAUSE

Corona pin grounds to the surface of the APGC ion chamber. Over time, this surface becomes very dirty and affects corona stability. 

FIX or WORKAROUND

Clean or replace the APGC chamber (700005457).

ADDITIONAL INFORMATION

See article wkb62827 on Atmospheric Pressure GC (APGC) Ionization?

See article wkb64495 on quickly testing for M+ to MH+ sensitivity using the APGC