formaldehide analysis

[dcobice]

Dear all,

I need to quantitate formaldehide in Ketone, I know that the common analysis method is derivatization with DNPH and PFBHA but in my case I cant ,because I have an interference with the ketone group that react to the reagent to form the oxime derivative and It will be an intereference in my chromatogram.
I think that I need to perform a GC/MS analysis.
do you know any STABLE and SPECIFIC reagent to derivatize formaldehide???? in a Ketone enviroment.

thanks in advance

D

[Consumer Products Guy]

Have you tried HPLC to assay for the DNPH-formaldehyde complex? That's what we use.

[Matt Savage]

We use the DNPH method as well. We did look at using NASH derivisitisation as well but our samples are highly reactive in aqueous systems so it was no use to us.

Nash method....

Reagent:

Ammonium acetate 150g
Acetic Acid 3g
Acetyl acetone 2g
Water 845g

Mix above solution 1 to 1 with your sample and leave for 1 hour on the bench and then HPLC it.

MAtt

[dcobice]

Have you tried HPLC to assay for the DNPH-formaldehyde complex? That's what we use.

Thanks for your reply, but I have a 1ppm concentration in Ketone, and I think that the reaction is kinetically unfavorable because I have a lot of ketone that react more than the aldehyde ( because of the concentration),
I guess that if I use PFBHA as a reagent and I will try GC/MS with SIM mode quantitaion of the molecular weigth adduct does it works??
do you have other ideas??

thanks again

[dcobice]

[quote="Matt Savage"]We use the DNPH method as well. We did look at using NASH derivisitisation as well but our samples are highly reactive in aqueous systems so it was no use to us.

Nash method....

Reagent:

Ammonium acetate 150g
Acetic Acid 3g
Acetyl acetone 2g
Water 845g

Mix above solution 1 to 1 with your sample and leave for 1 hour on the bench and then HPLC

Thanks .. but I tried it and I had not a good presicion method because I think that the adduct is not stable I had a RSD of the STD about 20% and I need a least 10% in the prescion assesment.
But I will try again perhaps I made a mistake during the preparatiion considering that the concentration that I can reach is very low!!! ( 1ppm i ketone matrix)
I you have other ideas are wellcome!!!

thanks