Application of a hybrid large pore mesoporous silica functionalized with β-cyclodextrin as sorbent in dispersive solid-phase extraction. Toward sustainable sample preparation protocols to determine polyphenolic compounds in Arbutus unedo L. fruits by UHPLC-IT-MS/MS

Abstract

A quick, sensitive and selective analytical reversed-phase method using ultra-high performance liquid chromatography coupled to an ion-trap mass spectrometry detector (UHPLC-IT-MS/MS) was employed for the simultaneous determination of nine phenolic compounds (PCs) in strawberry tree (SBT) berries. The sample treatment included a solid-liquid extraction followed by a dispersive solid-phase extraction (dSPE) procedure using a hybrid large pore mesoporous silica (LP-MS) functionalized with β-cyclodextrin (β-CD) as sorbent material. For this purpose, the initial synthesized LP-MS was modified with β-CD following three different synthetic routes, obtaining three new functionalized materials (denoted LP-MS-β-CD-R1, LP-MS-β-CD-R2 and LP-MS-β-CD-R3). All synthesized materials were comprehensively characterized, showing excellent textural properties, and they were also tested as sorbent materials in the extraction of PCs by comparison of SPE and dSPE procedures. The LP-MS-β-CD-R2 as sorbent material in the dSPE procedure showed the best potential to extract and purify the target PCs, being more effective than the other materials and compared with the SPE procedure. The performance of the proposed dSPE-UHPLC-IT-MS/MS method was validated in terms of selectivity, linearity, LOD, LOQ, trueness, precision, and matrix effect, achieving good analytical method performance and demonstrating its feasibility and practicality for the quantification of PCs in SBT fruits. The analysis of the investigated SBT berries revealed, mainly, high contents of arbutin reaching concentrations up to 5979 µg/g dry weight, followed by catechin (661 µg/g dry weight). Arbutin was, undoubtedly, the major PC determined in all SBT berry samples analyzed, being the most prominent and showing a high concentration compared to that of other polyphenols determined in other red berries.