Facile synthesis of boronic acid-functionalized magnetic metal-organic frameworks for selective extraction and quantification of catecholamines in rat plasma.

Xinying He,Yan Li,Yunqiu Yu

doi:10.1039/c8ra07356b

Abstract

Precise determination of the endogenous catecholamines, dopamine (DA), epinephrine (E) and norepinephrine (NE) faces substantial challenges due to their low physiological concentrations in plasma. We synthesized, for the first time, a magnetic metal–organic framework (MIL-100) composite with boronic acid-functionalized pore-walls (denoted as MG@MIL-100-B composite) using a metal–ligand-fragment coassembly (MLFC) strategy. The composites were then applied as an effective magnetic solid-phase extraction (SPE) sorbent for determination of trace catecholamine concentrations in rat plasma through coupling with HPLC-MS/MS. The obtained nano-composites exhibited high magnetic responsivity, uniform mesopores, large specific surface area, and boronic acid-functionalized inner pore-walls. Catecholamines in rat plasma were extracted through interaction between the cis-diol structures and the boronic acid groups in the MG@MIL-100-B composites. Extraction conditions were optimized by studying SPE parameters including adsorption and desorption time, elution solvent type, pH conditions and adsorbent amount. With our approach, the detection limits (S/N = 3) were as low as 0.005 ng mL−1 for DA and E, and 0.02 ng mL−1 for NE. Intra- and inter-day precision ranged from 2.84–6.63% (n = 6) and 5.70–11.44% (n = 6), respectively. Recoveries from spiking experiments also showed satisfactory results of 94.40–109.51%. Finally, the MG@MIL-100-B composites were applied successfully to determine catecholamine concentrations in rat plasma.

Highlights

Catecholamines, i.e. epinephrine (‘E’, known as adrenaline), norepinephrine (‘NE’, known as noradrenaline) and dopamine (‘D’), act as hormones or neurotransmitters peripherally and centrally.[1]
Characterization of MG@MIL-100-B composites The morphology of the MG@MIL-100-B composites was identi ed by Transmission electron microscopy (TEM)
The TEM images revealed that MG@MIL-100-B composites have a core–shell structure with a mean diameter of about 250 nm, and Metal–organic frameworks (MOFs) layer thickness of about 50 nm

Summary

Introduction

Catecholamines, i.e. epinephrine (‘E’, known as adrenaline), norepinephrine (‘NE’, known as noradrenaline) and dopamine (‘D’), act as hormones or neurotransmitters peripherally and centrally.[1]. Various methods have been developed to detect catecholamines in biological samples. Traditional analytical approaches involve high-performance liquid chromatography (HPLC) coupled with electrochemical,[5 ] uorimetric,[6] chemiluminescence,[7] ultraviolet or mass spectrometry (MS) detection.[8] these approaches are typically time-consuming, and are not sufficiently sensitive to quantify endogenous catecholamines. The application of liquid chromatography-tandem mass spectrometry (LC-MS/MS) in quantifying catecholamine concentrations has been progressively more common recently. This is due to the high selectivity and sensitivity of this method.[9]

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Conclusion