On-line derivatization coupled to flow injection permanganate chemiluminescence detection of total carbonyl compounds in natural waters and drinking water

This work describes the development of a fast assay for the determination of low molecular weight carbonyl compounds based on the oxidative chemiluminescence of 2,4-dinitrophenylhydrazine with acidic permanganate, which is enhanced during conversion to the corresponding phenylhydrazone-carbonyl derivatives. By exploiting the common derivatization pathway and oxidation mechanism of phenylhydrazones under kinetically controlled conditions in a flow configuration, a common light emission is produced which corresponds to the total aqueous concentration of carbonyl compounds. The experimental conditions that afford the optimum analytical features were optimized for acetone, acetaldehyde and formaldehyde which constitute the most abundant carbonyl compounds in environmental samples. The method was successfully applied to the determination of total carbonyl content in natural waters and drinking water at the low μg L−1 levels with satisfactory recoveries (94.0–99.5%) and very good reproducibility (RSD = 1.58–2.99%, n = 8, C = 2 μg L−1). Validation of the results was performed with gas chromatography suggesting that the proposed method provides a fast alternative to the routine screening of low molecular weight carbonyl compounds in natural waters.