Split with on-column injector?

[Fabiano]

We have an old Varian 3700 with a split/splitless injector and instead of the liner and the reduction for capillary columns we have an on-column insert/guide (maybe 10-15 cm long)for capillary columns .

The on-column insert fullfil all the liner space, "clogging" the split vent.

In theory, I can lower the on-column insert ( it´s easy just move the grafitte ferrule), create a chamber for injection and use the split vent.

However, I still don´t have the glass liner and any replacememnt part for this injector ( it was ended by Varian).

What are the chances of this idea works? direct injection on metal surfaces will create many losses, even packing the chamber with glass wool ?

My target compounds would be: chloroform, BTEX, chlorinated residual solvents and some pesticides.

Thank you
Fabiano

[Victor]

I don't know the answer to your question. However, the company Restek makes a number of different liners for various models of GC which are listed in their catalog. It might be possible to select a liner from the long list they have which might fit your GC, even if it is not exactly the right model. Alternatively, it is possible that they might custom make one for you, although I don't know what this might cost.

[chromatographer1]

Try a variety of companies for replacement liners. The ferrule is a standard 1/4" graphite or vespel. There should be MANY sources for replacement parts. Restek Supelco Alltech Ohio Valley etc etc etc.

A few free phone calls should solve your problems.

I used this GC with injector liners for other GCs in direct splitless mode. Go outside your normal thinking if you wish to use this old classic GC.

best wishes,

Rod

[Peter Apps]

To get your inlet back into split configuration cut a piece of 1/4 inch or 6 mm glass tubing to act as a liner (you do not really need a constriction at either end) and use a Swagelok 1/4 inch to 1/16 inch reducer (#SS-100-R-4) with a 1/16 inch vespel graphite ferrule to connect the column at the bottom of the inlet body.

The Varian 3700 GC represents the peak of design of instruments that could be modified and customized to particular applications. Am I the only one who gets nostalgic for GCs that could be modified in house, where flows and temperatures could be changed at any time without software telling you it is busy with a run ?

Peter

[chromatographer1]

Peter,

You are NOT the only one (sob). Sometimes the good old days WERE the good old days.

Rod

[DR]

5890s were nice, but I never objected to using a 3700.

[Fabiano]

Thank you Peter, I found a piece of a GC glass packed column that fits in my injector, it has a little more than 2 mm Internal Diameter (1/4 inch OD). I’ll try it in a few days, thanks again, Fabiano.