Chromatography Forum

Hey guys,

I use DNPH, as a premade solution from Sigma Aldirch in phosphoric acid, but it seems like this along with the solid powder form of DNPH is being discontinued everywhere.

I use this for analysis of aldehydes with a UV-Vis detector. Seems like DNPH is being discontinued by nearly all suppliers.

Does anybody have an alternative HPLC suitable method for detection of aldehydes?

Thanks.

A few years ago, Sobsey et al published a method for the quantification of MDA in plasma using 3-nitrophenylhydrazine (3NPH) as an alternative to DNPH. This might work for small aldehydes as well.

http://dx.doi.org/10.1016/j.jchromb.2016.07.013

Still available as DNPH powder? https://www.sigmaaldrich.com/US/en/prod ... ch/d199303

I see that the delivery date is projected to be next February.
I have in the past had issues with getting it shipped. Luckily no one has asked for that test for several years.

Maybe it has something to due with liability as DNPH can be explosive/dangerous.

But many chemicals are dangerous.....especially if proper precautions are not used. I imagine if gasoline or alcoholic beverages were invented today, their use would be banned....

The dry powder is a risk for explosions. Thus it is shipped wet.
EPA method 8315A (1996) has a recrystallization step as an appendix with no mention that it can be explosive when dry.

We were having problems with the 8315 test recently and the recrystallization step so we switched to the DNPH-HCL, corrected for molar concentration and it works great with even fewer impurities. We got it as soon as we ordered it so stock was good too, at least a couple months ago.

Don Shelly was the one who gave us that tip