Trimethylamine or TEA

[ydna1977]

Hi

Which is the suitable Ion pair reagent to use ?
What difference would each Ion pair usually make on peak separation ?
Ion pair will be combined with buffer and SLS for mobile phase with methanol
thanks

[DR]

Ion pairing agents are usually chosen at least in part as a function of the pH at which you need to run. Ideally, you choose a pairing agent that will afford you at least a little buffering capacity at your desired pH.

TEA is a common abbreviation for Triethylamine.
Did you mean to ask about whether to use TEA or TFA (Trifluoroacetic acid)?
If so, TFA is used at much lower pH than TEA.

[Consumer Products Guy]

In the consumer products field TEA is a nickname for triethanolamine.

[ydna1977]

No
asking about what is ' best' to use Trimethylamine or Triethylamine

[Consumer Products Guy]

"Best" is what works best for your individual situation. You determine that, that's what they pay you for.

[HPLCaddict]

Trimethylamine: gaseous
Triethylamine: liquid

I'd prefer to work with the liquid additive:)

[HPLCaddict]

"Ion pair will be combined with buffer and SLS for mobile phase with methanol"

SLS : sodium lauryl sulfate? That's your ion pairing additive!

Both TEA and TMA are no real ion pairing additives. Why do you want to add one of them at all? TEA was used in the old days for masking unwanted silanol interactions and thus improving peak shape. With modern, high purity silica columns, it's seldom needed anymore.

[ydna1977]

yes SLS ion pair and guess TEA or TMA used to decrease interactions and suppress tailing .. though on C18 column with this mobile phase I am not sure

[DR]

Clearly, I missed an "m".
Apologies.

[ydna1977]

Found TMA 33% in ethanol from a supplier as a replacement for just TMA

selectivity much improved compared to using same volume of TEA, so not just for improving peak shape here ?