Chromatography Forum

My ~3month old Varian 8400 ALS purchased on a 3800/2200MSD was working fine with standard red septa and was giving me glove matches with my HPLC for cannabis / terpinoid testings on a 30m column w. 0.25mm i.d x 0.25um coating.m (<4% RPD for six components).

Restek recently offered me a free 15m column of the same which stated that the analyses could be conducted within a 2min. time frame in lieu of the 12min one I had been using.

Upon changing the column, I changed my liner to a deact-wool filled 4mm o.d Sky-split/splitless liner liner but with Resteks brand of 9mm Thermo-green type septa.

Of course when changing the column you need to remove the ALS.

After replacing it, I noted that when calibrating the CP1177 injector, the needle would miss the center hole by ~0.5mm. Even when drilling out the center hole in the circular switch-top a bit, to allow insertion, it still was not centered, so I followed one of Varians former tech reps suggestion to re-mount the main screws on the CP1177 base while pressing the housing to the left with a screwdriver handle. This totally aligned the needle & showed NO tendency to bow/curve in any direction when calibrating it all the way down to the syringe base.

I have since bent 10 syringes even when using a very slow 5cm/sec injection speed at only 75% needle depth to allow for the extra wool present in the Sky liners.. WTF?!? is going on here.?

I have since purchased (From Restek) older 9mm red septa which have been partially cored & am praying for a cure, or getting an exorcist. Restek is great because of their quick shipping time of
only a day or two.... Verneyost MMTLMMJ.com 720-560-7166...Any other ideas?

Welcome.

If the instrument is only 3 months old it should still be under guarantee (but the Varian brand disappeared a few years ago, did you purchase second-hand ?) - in which case drilling holes in might not have been all that clever. Plainly you have an alignment problem that needs to be sorted out, but you may also be tightening the septum nut too much - over-compressed septa are more difficult for the needle to puncture.

As a general trouble-shooting tip; carrying on bending needles without changing anything, in the hope that the problem will go away by itself is not cost effective.

Peter