Dispersive liquid-liquid extraction based on magnetic Pickering emulsion followed by GC-MS/MS for the simultaneous determination of aldehydes in environmental water samples.

A dispersive liquid-liquid extraction based on Pickering emulsion stabilized with ferroferric oxide grafted nitrogen-doped graphitized carbon black has been developed to simultaneously determine seven aldehydes in environmental water samples, in combination with pentafluorobenzyl hydroxylamine precolumn derivatization GC-MS/MS. The nitrogen-doped graphitized carbon was prepared from dicyandiamide waste residue with a simple acid wash process. The effects of magnetic emulsifier amount, extraction time, solution pH, and oil/water volume ratio on the formation of magnetic responsive Pickering emulsion and the extraction efficiency of the proposed dispersive liquid-liquid extraction were also investigated. Under the optimized conditions, satisfactory linearities were obtained for all aldehydes with correlation coefficients larger than 0.9984. The LODs and LOQs of seven aldehydes were in the range of 17.3 approximately 30.1 ng/L and 54.3 approximately 103.4 ng/L, respectively, with intra- and inter-day RSDs less than 8.6%. The mean recoveries at three spiked levels ranged from 70.0 to 101.4%. With the Pickering emulsion as a "minimized extractor", the extraction was accomplished within 5 min. After extraction, the magnetic disperser could be recovered for reuse at least five times by an external magnetic field. The proposed method was demonstrated to be feasible, simple and economic for the trace analysis of the aldehydes in environmental water samples. This article is protected by copyright. All rights reserved.