Do-not-inject list

[Roxanne42]

One of my biggest challenges in managing this lab is trying to figure out the compatibility of the analytical instruments we have with the wide range of chemistry that is being investigated by the various research groups at the university.

I never know if it is okay to inject something on the column (GC-FID and MS mostly) or not. The fact that most of the chemistry is catalytic also means that the samples typically contain inorganics like Ru, Pd, Cr, Au catalysts that are typically involatile, as well as bases such as potassium carbonate.

We also analyze 96-well plates and the concentrations are typically low. Our inlets are equipped with glass fiber (and hopefully that can trap most of the involatiles) - when faced with 96-well samples, it often becomes impractical to filter out residues (and the commercial filter plates are not an option for us given their cost).

Are there certain components that one should ABSOLUTELY NOT inject unto the instruments? We currently do not have guard columns installed (it's on the list when we get more money!) so that is also an issue that worries me when looking at all those involatile inorganic catalysts!

Are bases that much of a problem? At what pH does it become an issue (we have typical HP-1 (1ms) columns at the moment)...?

Basically just looking for hints, tips and ideas as everytime someone comes in, I'm never quite sure how to look at it. But I would definitely like to preserve the instruments' integrity for the greater good of the lab!


Thank you!

Roxanne.

[gcguy]

Roxanne,

We were recently developed a method for some people who neglected to tell us about a compound in the sample matrix that broke down to form HF on heating. Our entire column stationary phase ended up in the detector. Always consider thermal stability or the formation of other compounds during gc analysis.

GCguy

[dirtandwater]

Hehe.. Our policy was to get a valid credit card number from the grad student who brought us the rank, sludgy tar he/she claimed was "cleaned up". Over time we learned who's work we could trust and who would have to sneak up on the instructional program GC's after hours for analysis.

Some of the researchers were very thorough and I could go through their processes, synthetic paths and reactant lists and get a notion of what sort of properties their "mystery yield" could have. There were quite a few who were an absolute pleasure to work with and I enjoyed facilitating their work. Some thought I was trying to steal their ideas and would get very defensive and angry when I asked any questions. Others, I think, were just mixing everything from the stock room in a flask, burning it up and having me analyze the residue with the hope that they accomplished something.

I have also known the joy of evacuating the stationary phase into the detector.

Good times...