Amino-functional metal-organic framework as a general applicable adsorbent for simultaneous enrichment of nine neonicotinoids

Four functional metal-organic frameworks (MOFs) were facilely synthesized through one-pot procedure or post synthetic modification method and used as adsorbents for simultaneous enrichment of nine neonicotinoids (NEOs) for the first time. Of which, amino-functional MIL-101-NH2 showed general high affinity towards nine NEOs and performed the best due to extraordinarily high surface area and specific interaction with analytes. A simple, efficient and robust method was developed by dispersive solid phase extraction with MIL-101-NH2 combining with liquid chromatography mass spectrometry (dSPE-LC-MS). Key factors that affecting enrichment efficiency were investigated and the established method demonstrated high sensitivity with detection limits as low as 0.02-0.1 ng/mL and wide linearity range over 3-4 orders of magnitude. Besides, compared with commercial SPE cartridges, this adsorbent showed superior enrichment efficiency and could be used for at least five times without obvious recovery decrease. The method was also applied for determination of trace NEOs in aqueous environmental samples and NEO contamination was found. This study demonstrated the practicability of facile synthetic MOF in simultaneous enrichment of nine NEOs and offered a simple and general method for trace amount NEOs sample preparation in real samples.

Automated summary

Four functional metal-organic frameworks were synthesized and used as adsorbents for simultaneous enrichment of nine neonicotinoids. Among them, amino-functional MIL-101-NH2 showed the best performance due to high surface area and specific interaction with analytes. A simple and efficient method was developed for trace analysis of neonicotinoids in environmental samples.