Laser-induced fluorescence and UV detection of derivatized aldehydes in air samples using capillary electrophoresis

In this work, two capillary zone electrophoresis methodologies using UV absorption detection (214 nm) and laser-induced fluorescence detection (He/Cd laser, 325 nm excitation, 520 nm emission) of selected aldehydes (formaldehyde, acetaldehyde, propionaldehyde and acrolein) derivatized with dansylhydrazine (DNSH, 5-dimethylaminonaphthalene-1-sulfohydrazide) were proposed and validated. The aldehydes react with DNSH to form negatively charged molecules in methanolic medium. In both methodologies, nine DNSH-derivatives, including isomers of acetaldehyde, propionaldehyde and acrolein and two impurities were baseline separated in 20 mmol l−1 phosphate buffer at pH 7.02, in less than 9 min. The limits of detection for the UV and LIF methodologies ranged from 1.1–9.5 μg l−1 and 0.29–5.3 μg l−1, respectively. The applicability of both methodologies to contemplate real samples was confirmed in the analysis of aldehyde–DNSH derivatives in indoor and outdoor air samples.