Development of magnetic graphene as an adsorbent and matrix for selective enrichment and detection of crotonaldehyde in saliva by MALDI-TOF-MS

Crotonaldehyde has long been regarded as an important environmental pollutant from cigarette smoke to human health. To have an efficient and high-throughput screening of crotonaldehyde in saliva samples, it is essential to develop an analytical method considering both enrichment and measurement processes. In this study, we proposed a novel method based on matrix assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) for the analysis of crotonaldehyde in saliva. Magnetic graphene was synthesized via a facile hydrothermal process, and then applied as an adsorbent and a matrix for MALDI-TOF-MS. Crotonaldehyde in saliva was derived by 2,4-dinitrophenylhydrazine first followed by a magnetic solid-phase extraction process and high-throughput MALDI-TOF-MS detection. Due to its large surface area, strong interaction force and excellent inherent properties, magnetic graphene showed a satisfactory ionization and enrichment performance for the enrichment and ionization of crotonaldehyde by MALDI-TOF-MS. The crotonaldehyde derivatives could be sensitively detected from saliva samples even at a low concentrations. The results indicated that the proposed method was simple, rapid, sensitive and efficient for the analysis of crotonaldehyde in saliva and other biological samples.