Do you Measure Formaldehyde (or other Aldehydes and Ketones) in Air?

Martin Perkins

13th November 2011

Aldehydes are Important Industrial Chemicals

If so perhaps you would be interested in a current project we are working on. We aim to automate the laboratory analysis of aldehydes in air, where samples are currently collected using NDMA air sampling tubes.

6,000,000 tons of Formaldehyde is manufactured each year. This is an important industrial chemical, used as a building block in the manufacture of many common polymers (urea formaldehyde resins, phenol formaldehyde resins and melamine are just a few).

However, formaldehyde is toxic and has ozone depleting properties, so it is common to check for residual levels of the compound in air, either in the workplace or in situations where humans might be exposed to residual formaldehyde out-gassing from finished polymers.

Not all aldehydes are toxic of course.  Aldehydes are important components in most naturally occurring and synthetic fragrances and the analysis of these compounds in air can be important for different reasons.

Airborne aldehydes are collected by drawing air through a sample tube containing 2,4-dinitrophenylhydrazine (DNPH). Carbonyl compounds react with the DNPH to form derivatives in the form of hydrazones which are immobilised on the sample tube. Back in the analytical laboratory, these compounds can be eluted from the sample tube with acetonitrile and analysed by HPLC with a UV detector.

If you are only running a few samples, the fact that the collection tubes have to be processed by hand may not be an issue, but some laboratories are running enough samples for this to be a problem. It is never good to have a skilled chemist performing, routine, mechanical tasks on lots of samples. Robots are (very) good at routine tasks – much better than humans, in fact. Analytical chemists are best employed using their brains and creativity.

We are currently developing a system to fully automate the whole analytical process. If you perform this analysis regularly and would like to free-up your staff for better things (and obtain better precision to boot), we are now at a point where your input would be very useful to us.

If you would like to know more, please call me on +44 (0)1954 212909 or email on