What's That Smell? Odor Analysis with Raptor Biphenyl

A wide variety of chemicals are used in the production of consumer goods, and most of them have odors that are released into the atmosphere and/or linger on the final product.   Everyone gets really excited about “new car smell,” but sometimes residual odors on fabric or plastic are off-putting. I noticed that the knock-off replacement FitBit bands were a lot smellier than the original, and it took a while for the plastic-y smell to fade. Specific chemicals and intensity levels can trigger nausea or headaches in sensitive individuals.

Regulations vary around the world for testing parameters, but some compounds that recently came to our attention from our office in Japan are six aldehydes specified in the Japanese Offensive Odor Control Law: acetaldehyde, propionaldehyde, n-butryaldehyde, iso-butyraldehyde, n-valeraldehyde and iso-valeraldehyde.  These short chain aldehydes have pungent, offensive odors described as earthy/musty or like rancid butter.

We currently have an application for DNPH derviatized aldehydes and ketones using a Raptor C18 column and our analyte list includes n-butyraldehyde, but the Japanese law calls for the identification of both n-butyraldehyde and iso-butyraldehyde. Our colleagues in Japan worked with one of their chemical testing customers who kindly provided these chromatograms showing that n- and iso-butyraldehyde can be separated with a Raptor Biphenyl column and a simple 25:75 water:methanol mobile phase. Run time was also reduced, enabling higher sample throughput. Both columns were 2.7µm particle size, 150 x 4.6mm. Analysis was done on a 600 bar LC system with a flow rate of 1 mL/min, 40C, and UV detection at 360nm.

If you're doing odor testing in plastic and resin products and need to separate butyraldehyde isomers, give the Raptor Biphenyl a try!