HPLC mobile phase additive

[Peter Apps]

Many years ago I worked with HPLCs, and some methods included an additive to the mobile phase whose name I do not recall. It was a volatile organic with a strong and distinctive odour, almost certainly a sulfur compound, possibly added as an anti-oxidant or to stop analytes interacting with metal surfaces.

Does it ring a bell with anyone?

[Multidimensional]

Possibly TFA ? This was grossly overused in the early days of LC (and still is by many newbies).. Initially added at 0.1 to 1% to aqueous phases to prevent unwanted interaction with the lower quality silica supports used (Type A).

[Peter Apps]

If TFA is trifluoroacetic acid, then no. This was a volatile.

[vmu]

Triethylamine (TEA).

If TFA is trifluoroacetic acid, then no. This was a volatile.

TFA is volatile too.

[Peter Apps]

Not triethylamine - I am pretty sure that it was a sulfur compound, possibly a thiol of some kind?

[bcd_GCLCMSMS]

Dithiothreitol (DTT)?

Used to prevent air oxidation of cysteine and the formation of disulfide bonds.

[vmu]

Thiodiglycol? However, it's BP is 165 C.

[Peter Apps]

Neither of those ring a loud bell - my recollection from more than 20 years ago is that the name was ........ ethanol.

[DR]

not -ol, but maybe Heptafluorobutyric acid (HFBA)
or Methanesulphonic acid (MSA)?

Neither has the mercaptan nor bisulfate smell, but HFBA can clear a room...

[Hollow]

Neither of those ring a loud bell - my recollection from more than 20 years ago is that the name was ........ ethanol.

one thing that come to mind would be mercaptoethanol.
Like used in the derivatization of amino acids with the OPA-method (o-phthalaldehyde derivatization)?

I wouldn't like to use it as a MP-additive but who knows?
Maybe it was a dedicated system with in-/online derivatization or other special method.

[Peter Apps]

Mercapto ethanol does sound familiar, and OPA was being used for derivatizations. Quite possibly I misremember it being used as a mobile phase additive - I wasn;t actually doing the analyses.

The reason it comes up is that its odour is very similar to a potential predator chemical signal, whihc is how I now earn my daily crust.

[lmh]

Mercaptoethanol was used by molecular biologists all over the place, in protein gels, all reaction mixes, in anything. You could recognise any biological research institution from miles downwind by the general air of mercaptoethanol. Only the occasional genetics institute would manage to outsmell it, by a concentrated mix of mouse, and drosophila food. It was quite a warm, sulphurous smell that ended up pervading everything. I wouldn't be surprised if a biologist decided to put mercaptoethanol in their HPLC buffers; they probably offered a dilute solution of it to their girlfriends/boyfriends as perfume/aftershave back then. Dithiothreitol came as a great relief to many of us, as although it also has a distinctive smell, it's a lot less potent.

[Peter Apps]

Warm sulfurous is about right for the odour. This was in an analytical chemistry lab, for an analysis that was done only occasionally, ans so we never got ahbituated to the smell.

[DR]

I left a job in part because I was starting to get habituated to a smell I really do not like.

[wss]

Would not surprise me if it was mercaptoethanol - we use it regularly as an additive in our LC system for mercury speciation using ICP-MS for detection. Distinctive warm sulfurous odour as you might expect...