Automated solid‐phase extraction of phenolic acids using layered double hydroxide–alumina–polymer disks

Abstract

The application of layered double hydroxide-Al O -polymer mixed-matrix disks for solid-phase extraction is reported for the first time. Al O is embedded in a polymer matrix followed by an in situ metal-exchange process to obtain a layered double hydroxide-Al O -polymer mixed-matrix disk with excellent flow-through properties. The extraction performance of the prepared disks is evaluated as a proof of concept for the automated extraction using sequential injection analysis of organic acids (p-hydroxybenzoic acid, 3,4-dihydroxybenzoic acid, gallic acid) following an anion-exchange mechanism. After the solid-phase extraction, phenolic acids were quantified by reversed-phase high-performance liquid chromatography with diode-array detection using a core-shell silica-C18 stationary phase and isocratic elution (acetonitrile/0.5% acetic acid in pure water, 5:95, v/v). High sensitivity and reproducibility were obtained with limits of detection in the range of 0.12-0.25 μg/L (sample volume, 4 mL), and relative standard deviations between 2.9 and 3.4% (10 μg/L, n = 6). Enrichment factors of 34-39 were obtained. Layered double hydroxide-Al O -polymer mixed-matrix disks had an average lifetime of 50 extractions. Analyte recoveries ranged from 93 to 96% for grape juice and nonalcoholic beer samples.

Polyethyleneimine‐modified porous aromatic framework and silane coupling agent grafted graphene oxide composite materials for determination of phenolic acids in Chinese Wolfberry drink by HPLC

“…Generally, the analysis of phenolic acids involves the elimination of impurities and determination of the concentration of the targets, which is carried out most by HPLC. Existing sample processing methods include SPE [6], solid-phase microextraction [7], magnetic solid-phase extraction [8], and pipette-tip solid-phase extraction (PT-SPE) [9]. PT-SPE is a miniaturization pretreatment technique which received widespread attention owing to simplicity, low cost, and remarkable reduction consumption of sorbents [10].…”

3D Printing in analytical sample preparation

“…Besides the use of beads as SPE materials, extraction disks based on SPE beads entrapped in a polymer matrix are also popular extraction supports enabling fast flow‐rates and a high analyte extraction efficiency [51]. Disk‐based SPE also facilitates the automation of the extraction procedure using low‐pressure pumps and extraction disks based on commercial [52,53] or lab‐made sorbents [54,55]. Calderilla et al.…”

Aqueous two-phase extraction technique based on magnetic ionic liquid-nonionicsurfactant for phenolic acids in grape, apple, pear, and banana

“…Chromatographic techniques such as high-performance liquid chromatography (HPLC) [6], gas chromatography (GC) [7], and high-performance thin-layer chromatography (HPTLC) [8] are used for the analysis of phenolic acids. These compounds must be separated and enriched from the complex matrix prior to their analysis for sensitive and selective determination [9,10]. Among these extraction methods, aqueous two-phase extraction (ATPE) is an economical and efficient technique.…”