Sensitivity enhancement for the analysis of naproxen in tap water by solid-phase extraction coupled in-line to capillary electrophoresis.
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 (C18) 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 microg/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 C18-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.
Macià
Alba
A
Departament de Química Analítica i Química Orgànica, Universitat Rovira i Virgili, Tarragona, Spain.
Borrull
Francesc
F
Calull
Marta
M
Benavente
Fernando
F
Hernández
Elena
E
Sanz-Nebot
Victòria
V
Barbosa
José
J
Aguilar
Carme
C
D019075:Electrophoresis, Capillary / Q000295:instrumentation* / Q000379:methods*; D009288:Naproxen / Q000032:analysis* / Q000737:chemistry; D012680:Sensitivity and Specificity; D052616:Solid Phase Extraction / Q000295:instrumentation / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014881:Water Supply / Q000032:analysis*
D014874:Water Pollutants, Chemical; D009288:Naproxen