Simultaneous determination of p-hydroxybenzoic acid and parabens by capillary electrophoresis with improved sensitivity in nonaqueous media |
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Authors: | Blanco Eva Casais María del Carmen Mejuto María del Carmen Cela Rafael |
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Affiliation: | Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Santiago de Compostela, Spain. |
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Abstract: | New methods based on nonaqueous capillary electrophoresis (NACE) were developed as promising alternatives for the simultaneous separation and determination of p-hydroxybenzoic acid (PHBA) and a group of parabens (methyl, ethyl, propyl, butyl and benzyl p-hydroxybenzoates), with good resolution and excellent sensitivity. As an effective on-line preconcentration technique, large-volume sample stacking (LVSS) was successfully combined with NACE allowing significant sensitivity enhancement. Identification and quantification of the analytes were performed by diode array detection (DAD). The influence of different parameters, such as buffer apparent pH, concentration of electrolyte, temperature, applied voltage and sample volume, on the efficiency, resolution and sensitivity of the electrophoretic separation was studied. The analytical performance was evaluated, and both NACE-DAD and LVSS-NACE-DAD methods showed good linearity, precision and instrumental LODs at low ng/mL levels. These LODs were compared with those described in the literature, and it was found that NACE-DAD method was comparable to GC-MS, while LVSS-NACE-DAD procedure achieved sensitivity similar to LC-MS, LC-MS/MS and GC-MS/MS, even using conventional ultraviolet-visible absorption detection. To test their suitability, proposed methods were evaluated for the analysis of PHBA and parabens at low and sub-ng/mL levels in environmental water samples. |
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Keywords: | Large‐volume sample stacking Nonaqueous capillary electrophoresis Parabens p‐Hydroxybenzoic acid |
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