Automating the Measurement of Formaldehyde and Acetaldehyde in Air

Martin Perkins

16th January 2014

We have developed a fully automated solution for the processing of DNPH tubes and the analysis of the resultant extracts. This instrument – the Anatune 300, is based on an Agilent HPLC platform and uses a dual head GERSTEL MPS to process the sample tubes. You can find an application note describing this system and the application here.

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.

New regulations aimed at reducing people’s exposure to short-chain aldehydes are coming into play and this means that labs will need to run many more samples.

Recognized methods for the analysis of airborne aldehydes collect samples 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 immobilized on the sample tube. Back in the analytical laboratory, these compounds can be eluted from the sample tube with acetonitrile and analyzed by HPLC using a UV detector.

Although the elution process is fairly simple, some care has to be exercised to achieve reliable results and the inherent vagaries of vacuum manifolds don’t help in this respect. Not everyone is able to get reliable data.

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. There are better ways to employ skilled chemists.

If you perform this test and want to know more about how this system could improve your work-flow, please email or call +44 (0)1223 279210.