I have noticed that the GSQ PLOT column (J&W, now Agilent)has great stability.
I've been abusing them for years, and have never had one clog up like some
PLOT columns are known to do. Disconnecting a PLOT column without first
bleeding off the head pressure is usually a recipe for disaster, but doesn't
bother the GSQ at all.
University of Victoria
>===== Original Message From Stable Isotope Geochemistry
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>We're having problems with the PoraPlot-Q capillary column (0.32) that
>came with our GasBench. We've been able to run with the He pressure ~18
>to 20 psi and have ~2+ mL/min flow rates. After swapping it out for a
>molesieve column, it's back in and now requires 25 psi for ~1 mL/min
>flow rates checked at end of column. I've check connections, clipped
>column ends, baked it out--but to no avail so far. No evidence for
>water/phosphoric acid on column (had that happen before, clipped off
>brown section of column). Would other Q-Plot columns work better, e.g.
>Supelco (they claim to fuse polymer to the silica column)?