Dual injections vs. Y press-tight column connectors

[MichaelVW]

We do PCB analysis on a 5890 with two ECDs. We've been using an old Cobra A/S to do the injections, but it might need to be replaced. Dual injection autosamplers look expensive so I'm thinking about trying to split the flow from a single injection to two columns.

Would anyone who has tried this like to comment on how well it works, anything to be aware of, etc?

[Steve Reimer]

We did that for years on 5890s, 6890s and some old Tracors.
The Y connectors were somewhat fussy to get leak free. But the higher volume of flow in the inlets helped keep DDT breakdown in check on the nasty (fish/heavy oil) samples.

[James_Ball]

Glass Y connectors are good, but as Steve said, can be difficult to make leak free unless you are used to using such press tight unions. We use these https://www.restek.com/en/products/acce ... tors/3355/ with the vespel graphite ferrule adaptor they seal well. Usually after the first few oven cycles you need to re-tighten the nuts, but after that they stay sealed. We use them for all our dual column test, PCB, PEST, HERB, and HAA analysis.

I like to use a guard column one size larger than my analytical columns, but that is just my preference. To do that you need to order extra ferrule adaptors in the right size.