Covalent-organic frameworks as adsorbent and matrix of SALDI-TOF MS for the enrichment and rapid determination of fluorochemicals

An imine-linked two-dimensional covalent organic framework, via the condensation of 1, 3, 5-triformylbenzene and p-phenylenediamine (COF-LZU1) is used as both adsorbent and matrix of SALDI-TOF MS for the rapid analysis of fluorochemicals. COF-LZU1 can efficiently assist the laser desorption/ionization of fluorochemicals and function well in negative ion modes without background interference. COF-LZU1 with large surface area, high porosity and suitable hydrophobicity, also can enrich trace amounts of fluorochemicals from solution effectively and quickly through hydrophobic interaction. Therefore, COF-LZU1-solid-phase extraction (SPE) enrichment is combined with SALDI-TOF MS measurement to provide the rapid and high sensitive analysis of fluorochemicals in water samples. The LODs of fluorochemicals can reach ppt or subppt levels. Besides, this method shows robust anti-interference ability. With the assistance of COF-LZU1, trace levels of fluorochemicals could be quantitatively and sensitively analyzed from environmental water samples in a rapid, sensitive and convenient way.