Determination of formaldehyde and other aldehydes in industrial surfactants by liquid chromatographic separation of their respective 2,4-dinitrophenylhydrazone derivatives.

A rapid and simple method for the determination of formaldehyde, acetaldehyde, and propionaldehyde in surfactants by derivatization with 2,4-dinitrophenylhydrazine (DNPH) has been developed. Samples are prepared in small vials containing a solution of DNPH and acetonitrile. This procedure allows direct injection of an aliquot of the sample into a liquid chromatograph (LC) for analysis. Separation and quantitation of the derivatives can be performed using reverse-phase liquid chromatography. Detection limits for formaldehyde, acetaldehyde, and propionaldehyde are 0.1, 0.1, and 0.5 micrograms/g, respectively, for a 1 g sample of the surfactant. The technique has been applied to other ethoxylated and propoxylated polymeric materials with equal success.