Column No longer Elutes Ammonia

As you can see, you have one seemingly silanized porous polymer and one basic deactivated one in the mix. QS was historically a silanized polymer as the purity at that time was poor, it is nowadays a high purity polymer without silanization. You also see that any separation is done by the QS, the CS103 has not enough surface area.

You could test the single columns if ammonia still elutes from either of them and then decide if you silanized the QS or treat the CS103 with a high ammonia injection.

Forgive my ignorance, as I am still relatively new to the chromatography space. I have two additional questions.

1. What would treating the CS103 with a high ammonia injection accomplish (Chemically, I mean)?

2. You state that the QS provides all the separation for the injection, so what purpose did the CS103 serve when attached afterwards?

Any help you provide is greatly appreciated, as always. 

You normally have two or more columns when using switching techniques, possibly CS103 as a pre-column that is later backflushed to vent while the analysis continues on QS. Something like that.

Treatment with ammonia would saturate possible acidic sites that might bind the ammonia.

More info/advice would only be possible if I know how the columns are put into your system (and their dimansions) or is it one column with two packings?

12 ft x 1/8” O.D. ss, packed with 4% KOH on 100/120 mesh Porapak QS 

5  ft x 1/8” O.D. ss, packed with 4% KOH on 100/120 mesh Chromasorb 103 

These two columns are joined together, the QS column first followed by the C103.

I do have anhydrous ammonia that could be used to treat the column, unless that is too high of a purity to use. Thanks again.

Deactivation is not necessary as these phases contain 4% KOH and are made for the analyses of basic components. The KOH would also immediately degrade any HDMS or TMSCl injected. Looking at this combination the CS103 part is - in my opinion - useless with no switching involved. A 13 ft. QS/4% KOH would do exactly the same (retention time).

These hases could not be the culprit of absorbing NH3. Maybe you injector (liner?) is absorbing the ammonia, but then 20% ammonia in the sample would break-through. Same for the TCD (I assume you use as detector).

Deactivation is not necessary as these phases contain 4% KOH and are made for the analyses of basic components. The KOH would also immediately degrade any HDMS or TMSCl injected. Looking at this combination the CS103 part is - in my opinion - useless with no switching involved. A 13 ft. QS/4% KOH would do exactly the same (retention time).

These hases could not be the culprit of absorbing NH3. Maybe you injector (liner?) is absorbing the ammonia, but then 20% ammonia in the sample would break-through. Same for the TCD (I assume you use as detector).