Chromatography Forum

Dear,
In our HS-analysis we find 2.2-DCPA to break down during the run. QC-standard-respons lowers by 50% after +/-15h (~30 samples).
Does anyone know if this breakdown is induced by temperature our by exposure to light?

We'd like to try to add a labled 2.2-DCPA standard, but I have some trouble finding one at our usual suppliers (Dr. Ehrenstorfer, Sigma-Aldrich, Chemlab).
If you know where to buy one, please let me know.

kind regards
MB

This breakdown is associated with time/temperature. 12 hour CCV checks don't normally pass for this and a couple of other more reactive compounds. The ability to chill samples helps recoveries significantly.

If the breakdown is through loss of HCl then a lower pH should help.

More info.
If you are running P&T that cpd is sensitive to heat related breakdown if exposed metal in the flow path.
I desorb @ 250 using a Vocarb 3000 trap with no problem.

If the breakdown is through loss of HCl then a lower pH should help.

I run this by purge and trap all the time with standards and samples preserved to pH<2 and it still breaks down unless it is chilled to below 10c. The cooler the room temperature the better the recoveries will be if you are not using a chiller on your autosampler. I would imagine it would be the same if you are doing injections instead of purge and trap also.

We are using a regular head-space with a cryo-module on the anal. column at -150°C.
Our tray's are uncooled so in a lab without airco the temperatures are at 20-25°C (even higher in mid-summer)

Does anyone know if there is a labled 2.2-DCPA available?
It should break down at the same rate as the native one and thus allow us to correct for this breakdown.

Not sure if there is a labeled analog for that, but you could contact Cambridge Isotopes www.isotope.com and see if they have one.