Chromatography Forum

Does anybody have any experience in splitting one inlet onto two columns using a "Y-connector" such as Resteks Universal Y-Presstight connectors? If so, is this a very efficient method for conformational analysis. How reliable are they? I am currently using two inlets with one column connected to each. I am using a staggered injection. However, with these Y-connectors, I can eliminate the staggered injection and have my conformation off of a single injection.

These are great for general purpose use with FID and TCD and other non-MS detector systems.

However, they are somewhat fragile, and are VERY OPERATOR DEPENDENT for a successful use. If not installed optimally, they may have slight leaks. The primary factor is the thickness and quality of the column exterior coating of polyimide.
(finger prints, thinness of polyiminde coating, defects in coating, stress breakage during installation or heating of oven, dirt, and serendipity are other factors)

Using a T connector with ferrules and nuts is a better, more easily installed device.

But your mileage may vary. It is worth a try

Rod

I would mainly be using the connector for 552 Haloacetic Acids. I run a large amount of samples (70 or more) in a single run, and am looking for ways to decrease run time. I'm a big fan of Resteks products so I use the CLP1 and CLP2 column pair. I'm going to try out Resteks Y press tight connectors with the Secure connector to ensure it seals properly. Hopefully my peak shapes will remain acceptable and I'll be able to protect my column by using the guard column.

I have also used Restek connectors with great success over the years. I never used the press-fit type but used the deactivated steel unions 0.010" (0.25mm) ID with graphite ferrules. Never had a leak or any problems.

good luck,

Rod

I have an in-house heart cutting setup that uses four Siltek Y presstights and two Siltek straight connectors - the air levels at the MS on the second deimension column are lower than I usually get with a split-splitless PTV inlet.

Peter

you are good.

Enough said.


Rod

I never had good luck with those press tight connectors nor the ones using the cage. I have great luck with the MXT connectors ( silcosteel disk with ferrule connections). I use them for all my dual column ECD methods.

[quote="jss37992"] I am currently using two inlets with one column connected to each. I am using a staggered injection. However, with these Y-connectors, I can eliminate the staggered injection and have my conformation off of a single injection.[/quot

I would suggest a change in your equipment as well as your configuration. Inject the sample into one injection port and split it on to two columns at the source while splitting your detector signals. I have been running dual column ECD analyses for years this way. Bag the Y connectors and use a two hole ferrule (agilent part number 5062-3580 for an agilent inection port). This also eliminates the need for a guard column, unless of course you want one.

My system = Agilent 6890 with dual micro ECDs. Single splitless injection through a 4mm gooseneck liner with a two hole ferrule. Primary column = 30 m DB5, secondary column = 30m XLB (or CLP1). I Catch the signal as two linked files.

Definitely recommend the dual column one inlet approach, I use Restek adapter #27185. Make sure you have the gold seal with a large enough opening, the correct insertion distance (> 30mm), and give the nut an extra turn, it seems to slacken after a few runs. Also need a recessed gooseneck liner (#20983), and I inject 2ul to account for both columns.
I never had any luck with the press tight connectors, straight or Y, they always started leaking on me.

I also would be interested in your experience with HAAs, we only run about 100/yr, but I always have trouble with either the surrogate or TCAA failing QC requirements. I suspect it has to do with the extraction, and want to try out 552.3 at some point to see if that works better. I didn't like coelutions with the CLP2 column, a 1701 works and separates well with HAAs.

Good topic. Press-tights have being around for a while, and are still widely use. However, is not 'til you use a press-tight in a GC/MS that you see all that air going through your column, even if you got a good seal.

I think that right now, SGE is in top of the game, regarding column connectors. My GCxGC chromatograms improved drastically once i started to use their SilTite micro-unions, reproducibility was better, column bleeding decreased. For Y-connectors, they have what they call a fixed-inlet splitter, and if you want to split between detectors, they have the fixed-oulet splitter, the only difference is that you can but the outlet splitter at different ratios 1:1, 5:1, 10:1 i think.

well, that's my two cents

Thank you for the input everybody! I am still fairly new at GC. I have a little less than a year of experience at HAA's but i get excellent recoveries on all of my compounds even when running a large amount of samples consecutively. My lab uses 552.3 and recoveries are typically 90% or better. I think for this go around I am going to try out Resteks universal Y-presstight connector. I have two columns that need replaced soon and I can get a column kit that contains a 5 meter guard column and the Y-connector for the same price as two individual columns. I typically get around 6 months use on a pair of columns. Hopefully the Y-connector will stay sealed for the duration of the column life. My theory is the guard column will really help protect my columns from "junk" so in theory I should get a longer column life as well.

Handle the y connector with care. They snap SO EASILY.

best wishes,

Rod

The more I look at it the MXT Y-connector looks like a better choice. I can re-use it and it looks much easier to install!

Glad you took my advice with the metal deactivated connections.

I hope it works for you. Be sure to get flat right angle cuts of the column ends and have them touch the center passage when you tighten the ferrules.

Rod

you are good.

Enough said.


Rod

That's as maybe - but all I was trying to say is that the Silteks do give an air-tight seal. I must admit through that I take a lot of trouble, and often several attempts to get a really clean square cut on the silica. The disadvantage of any of the push to seal connectors is that breaking and re-making connections is really hit and miss; often the seal is so tight that the tip of the silica is left in the taper of the connector. I am tempted to use metal compression fittings where the gas switch plumbing connects to the columns.

Peter