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Automated solid‐phase extraction of phenolic acids using layered double hydroxide–alumina–polymer disks
Author(s) -
Ghani Milad,
Palomino Cabello Carlos,
Saraji Mohammad,
Manuel Estela Jose,
Cerdà Víctor,
Turnes Palomino Gemma,
Maya Fernando
Publication year - 2018
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201701420
Subject(s) - extraction (chemistry) , solid phase extraction , hydroxide , chemistry , chromatography , tetrabutylammonium hydroxide , matrix (chemical analysis) , detection limit , polymer , elution , ion exchange , phase (matter) , monolith , phosphoric acid , analytical chemistry (journal) , inorganic chemistry , ion , organic chemistry , catalysis
The application of layered double hydroxide–Al 2 O 3 –polymer mixed‐matrix disks for solid‐phase extraction is reported for the first time. Al 2 O 3 is embedded in a polymer matrix followed by an in situ metal‐exchange process to obtain a layered double hydroxide–Al 2 O 3 –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 2 O 3 –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.