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- Joined: Wed Aug 02, 2017 8:10 pm
I recently implemented a good procedure for ethylene glycol quantitation out of biologicals. The method uses phenylboronic acid as the derivative, and analysis of 20uL of acetone containing the analyte via a headspace analysis (Gerstel gastight syringe + Agilent GC/MS).
Works great, super simple, very accurate - just one problem. After analysis we get a lot of ghost peaks on blank chromatograms, and c'graphy seems somewhat degraded in general. Often the column is replaced.
Does anyone have a suggestion about restoring the instrument performance short of column replacement?
edit: more specific method points: 100uL of sample, plus 400uL of 5ug/mL PBA in acetone. Vortex. Remove 20uL of acetone to a 10mL headspace vial and cap. Equilibrate on the Gerstel, and inject 100uL (1000uL syringe) on column (DB-5/equivalent). Temperature ramp on GC/MS, max 280 held for 5 minutes (Gerstel is flushed out at maximum available temp and time). Instrument is switched back to liquid injection mode when the glycols are done for the quarter, and that's when we really notice the degradation in performance.