Black stain on the sample needle and needle guide of an ACQUITY UPLC I-Class SM-FTN - WKB31600

SYMPTOMS

• Black stain on the outside of the needle and the inside of the needle guide (not seen anywhere else on the SM-FTN)
• Retention time shift

ENVIRONMENT

• ACQUITY UPLC I-Class Sample Manager - FTN

CAUSE

Unknown, but possibly due to the sample composition (chemical and physical characteristics)

FIX or WORKAROUND

Replace the sample needle (700008977 - 15 µL, SS). 

ADDITIONAL INFORMATION

Ensure that the SM-FTN wash line solution is suitable for the method. The wash solvent must be strong enough to dissolve any remaining sample, and the wash duration must be long enough to remove residue from the system.

Also see:

•  ACQUITY UPLC Sample Manager - Flow Through Needle Overview and Maintenance Guide (715005051)
•  ACQUITY UPLC I-Class System Guide (715005704)

Ensure that solvent mixtures are regularly renewed. Check for pH variation with a suitable pH indicator tool.

Explore the possibility of increasing the “Pre inject Wash” and “Post inject Wash” times.