Cannot see heptacosa in APGC source after switching from ESI source - WKB88137

SYMPTOMS

• Cannot see heptacosa in APGC source after switching from ESI source

ENVIRONMENT

• Xevo G2-XS
• Xevo G2-S
• Xevo TQ-XS
• Xevo TQ-S

CAUSE

Loose ion chamber. The screw into the ion source block is not tight.

FIX or WORKAROUND

1. Refit the ion chamber (700005457).
2. Ensure that the ion chamber is tight and flush with the ion block.

ADDITIONAL INFORMATION

Ensure that the heptacosa is fresh. It is extremely volatile and may have evaporated from the vial even if liquid is present. Also, use a large capillary in the vial cap to defuse heptacosa into the source. Depending on capillary size, it can take 10 to 30 minutes for the heptacosa profile to stabilize. If the capillary is too small, the sensitivity and profile may be very weak. You can test the heptacosa by carefully removing the cap on the vial and "flooding" the source with heptacosa gas to see if the capillary is restricting gas flow.