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)?