Chromatography Forum

Can anyone explain why I would see larger %RSDs for polar solvents like MeOH, EtOH, ACN vs. less polar solvents such as DCM, MTBE, and IPAc when they are all contained in the same standard solution? For example, out of 6 injections, %RSD for MeOH = 25%, DCM = 1.6% The peak areas for these two were similar under my conditions.

Diluent = DMSO/water. 1000 uL static HS injection split 10:1. Incubation temp 100C, inc. time 10 min, syringe temp 110C.

From here I see the biggest problem is too high a temperature in heating the vial. 100°C with an aqueous solution of DMSO is just demanding inconsistency.

A non-inert transfer line, sample loop, and contaminated column are other likely issues.

best wishes,

Rod