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Sensitivity enhancement for the analysis of naproxen in tap water by solid‐phase extraction coupled in‐line to capillary electrophoresis
Author(s) -
Macià Alba,
Borrull Francesc,
Calull Marta,
Benavente Fernando,
Hernández Elena,
SanzNebot Victòria,
Barbosa José,
Aguilar Carme
Publication year - 2008
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.200700593
Subject(s) - chromatography , naproxen , chemistry , capillary electrophoresis , tap water , elution , ammonium acetate , solid phase extraction , sorbent , extraction (chemistry) , sample preparation , analytical chemistry (journal) , capillary action , aqueous solution , high performance liquid chromatography , adsorption , materials science , medicine , alternative medicine , organic chemistry , pathology , composite material , environmental engineering , engineering
Abstract SPE coupled in‐line to CE, as the strategy to enhance the concentration sensitivity in CE, has been used to enrich naproxen in tap water samples. In this study, a microcartridge containing an octadecyl silica (C 18 ) sorbent was placed near the inlet within the separation capillary column. The optimum conditions were obtained when naproxen in an acidic aqueous solution (pH 3.5) was loaded into the capillary at 930 mbar for 30 min, and 20 mM ammonium acetate in methanol/water (70:30 v/v) was used as both an elution solution and a separation BGE. Under these conditions, the sensitivity was enhanced 1820‐fold with respect to normal hydrodynamic injection, and the LOD achieved was 0.2 μg/L. To show the capability of the in‐line SPE‐CE method, tap water samples were analysed after a pretreatment consisting in an off‐line C 18 ‐SPE procedure. The recovery of this procedure was higher than 80%. Under these conditions, naproxen could be detected at a concentration of 10 ng/L; so the potential of the procedure for the sensitive analysis of this type of drugs in water samples was demonstrated. Afterwards, these results were compared with those previously obtained for naproxen in water samples using different sample stacking techniques.