NH 2 NH-MOF: a reaction matrix for the specific determination of small aldehydes by MALDI-MS.

Efficient determination of aldehydes by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is hampered mainly by the low mass and unstable nature of analytes. In the present work, we propose a combined strategy of a reactive metal-organic framework (MOF) matrix for the derivatization and detection of aldehydes. A novel reactive MOF matrix (NH 2 NH-MOF) was synthesized in two steps. First, NR 3 + -MOF was synthesized via Cu 2+ and the quaternary amine ligand 4,4'-bipyridinium, 1,1″-(1,2-ethanediyl)bis-, dibromide (PyEtBr). Then, -NHNH 2 was introduced to NR 3 + -MOF through electrostatic adsorption between the -NR 3 + and -HSO 3 - of 4-hydrazinylbenzenesulfonic acid to synthesize NH 2 NH-MOF. The acid-base chemistry of NH 2 NH-MOF led to uniform cocrystallization of the aldehyde-matrix mixtures and helped to achieve the detection of low-weight aldehydes with good relative standard deviations (RSDs = 0.07-12.35%). It was confirmed that this strategy can accurately quantify formaldehyde, valeraldehyde, and benzaldehyde with good linearity (r > 0.97). Furthermore, this strategy was applied to quantitatively detect benzaldehyde in wastewater, thus showing potential applications in environmental pollutant detection.