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Determination of phthalates in beverages using multiwalled carbon nanotubes dispersive solid‐phase extraction before HPLC–MS
Author(s) -
GonzálezSálamo Javier,
HernándezBorges Javier,
Afonso María del Mar,
RodríguezDelgado Miguel Ángel
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.201800192
Subject(s) - phthalate , chromatography , chemistry , phthalic acid , extraction (chemistry) , detection limit , dimethyl phthalate , solid phase extraction , tap water , diethyl phthalate , sample preparation , mineral water , organic chemistry , materials science , metallurgy , environmental engineering , engineering
A microdispersive solid‐phase extraction method has been developed using multiwalled carbon nanotubes of 110–170 nm diameter and 5–9 μm length for the extraction of a group of nine phthalic acid esters (i.e., bis(2‐methoxyethyl) phthalate, bis‐2‐ethoxyethyl phthalate, dipropyl phthalate, butylbenzyl phthalate, bis‐2‐ n ‐butoxyethyl phthalate, bis‐isopentyl phthalate, bis‐ n ‐pentyl phthalate, dicyclohexyl phthalate, and di‐ n ‐octyl phthalate) from tap water as well as from different beverages commercialized in plastic bottles (mineral water, lemon‐ and apple‐flavored mineral water, and an isotonic drink). Determination was carried out by high‐performance liquid chromatography coupled to mass spectrometry. The extraction procedure was optimized following a step‐by‐step approach, being the optimum extraction conditions: 50 mL of each sample at pH 6.0, 80 mg of sorbent, and 25 mL of acetonitrile as elution solvent. To validate the methodology, matrix‐matched calibration and a recovery study were developed, obtaining determination coefficients >0.9906 and absolute recovery values between 70 and 117% (with relative standard deviations < 17%) in all cases. The limits of quantification of the method were between 0.173 and 1.45 μg/L. After the evaluation of the matrix effects, real samples were also analyzed, finding butylbenzyl phthalate in all samples (except in apple‐flavored mineral water), though at concentrations below its limit of quantification of the method.