A new fluorescent probe for sensitive detection of carbonyl compounds

A new method for the convenient and sensitive detection of aldehydes and ketones in environmental samples was developed. This method is described in detail for the measurement of carbonyls in water samples, but it is also potentially applicable to their determination in air. Derivatization of carbonyls is performed using N-(5-dimethylamino-1-naphtalenesulphonamido)-3-oxapentane-1,5-dioxyamine (dansyloxyamine, DNSOA). The resulting oxime ethers are separated by using reversed phase liquid chromatography and fluorescence detection. Parameters influencing both reactivity and sensitivity are discussed. The oxyamino function allows efficient chemical derivatization in water without the use of a catalyst. The dansyl fluorophore and the reactive oxyamino group are linked by an etheral chain which leads to very similar fluorescence responses for formaldehyde, acetaldehyde and acetone derivatives. The detection Limit of this method compares favourably with classical methods. Furthermore, the analysis procedure is easily set up and can be directly applied to environmental water samples. (C) 1999 Elsevier Science B.V. All rights reserved.