GC Test Method for Residual Formaldehyde in Herbal Extract

[Terry]

Dear all,

I am searching for a GC test method for residual formaldehyde in herbal extracts, any suggestion appreciated.

Terry

[chromatographer1]

The best method would be to react the formaldehyde with a reagent that allows analysis by HPLC.

Unfortunately after 30 years of trying to analyze formaldehyde in air and in other matrices by GC accurately, I have given up and have decided that LC is a better solution.

Formaldehyde is just too reactive and it even reacts with itself !

I cannot remember the chemical used at this time. You should be able to find it as you seek a HPLC method for formaldehyde. Simply allow the extract to come into contact with the reagent. Then inject the reagent onto a HPLC with UV detector. This reagent is used to measure formaldehyde in air over a period of time.

good luck and I wish my memory was better.

Rod

[AICMM]

DNPH? There are standards for DNPH derivatized formaldehyde available if I am not mistaken.

I have seen it done directly but it is extremely challenging.

Best regards,

AICMM

[chromatographer1]

The LC conditions have to be done just right to separate the derivative from the reagent.

Dinitrophenylhydrazine is the chemical in question.

I believe a tech note was published at Supelco.

best wishes,

Rod

[Terry]

Thank you for your information, I will try to get the reference.

[chromatographer1]

Also look at kits to monitor air quality (formaldehyde). You might flow nitrogen/inert gas through your herbal extract to release the HCO into a formaldehyde trap (containing DNPH) which then would react and be extracted and measured by LC.

You could manually spike your extract for recovery studies in this manner.

best wishes,

Rod

[JI2002]

I agree HPLC is a better approach. There is a report for analysis of formaldehyde in air by GC/MS. The method is not as robust as method TO11.

http://www.entechinst.com/pdf/Formaldeh ... rAir04.pdf

chromatographer1, in addition to reactive nature of formaldehyde, what were the other challenges you had developing GC method?

[chromatographer1]

Separation was not an issue, I had no interferences. But the reactivity and non-reproducibility were the real problems. The dimer and trimer of formaldehyde were also present and variable in their content.

Of course, an FID was not a suitable detector. Very low response. And the chromatographic system had to be both clean and inert, both column and sample injection system.

best wishes,

Rod