What could be the source of mass unit 53 adducts in my BioResolve RP mAb column separation using the IonHance DFA in my mobile phase? - WKB67828

SYMPTOMS

• Did not see mass unit 53 in LC/MS chromatograms using a different reverse-phase column and TFA mobile phase additive.

ENVIRONMENT

• BioResolve RP mAb
• IonHance DFA

CAUSE

Ammonium chloride, iron at elevated levels. Customer used Milli-Q water system and glass mobile phase containers.

FIX or WORKAROUND

Use of LC/MS water recommended to reduce prevalence of ions.

Use of LDPE containers (186009110) recommended.

ADDITIONAL INFORMATION

Milli-Q water systems use a municipality source and deionize the water. Municipality, system-wide water flushes produce larger amounts of ions in the water. The lab Milli-Q and TOC readings were within specification for HPLC-grade water.