title: Combination of solid-phase extraction and large-volume stacking with polarity switching in micellar electrokinetic capillary chromatography for the determination of traces of nonsteroidal anti-inflammatory drugs in saliva.
abstract: A reliable MEKC method for the identification and quantitation of traces of the nonsteroidal anti-inflammatory drugs (NSAIDs) ketoprofen, fenbufen and indomethacin in saliva is proposed. Using CE to analyze biological samples often requires suppressing the interferences and peak broadening typically resulting from high-conductivity sample matrices. We addressed this problem by using Microcon, a centrifugal filter device, to reduce the viscosity of saliva and exclude most higher-molecular-mass substances. This initial pretreatment was followed by the combined used of off-line SPE to isolate and concentrate the analytes, and large-volume stacking with polarity switching (LVSS) in the capillary. These two preconcentration steps allow the determination of NSAIDs at concentrations above 0.1 microg/L; therefore, the proposed SPE/LVSS/MEKC method affords a 500-fold sensitivity enhancement relative to conventional CE injection. The LODs obtained afford the determination of NSAIDs in saliva, where analytes can be present at the microgram-per-liter level.
authors.affiliation: Department of Analytical Chemistry, University of Córdoba, Córdoba, Spain.
authors.forename: Sara
authors.initials: S
authors.lastname: Almeda
authors.forename: Lourdes
authors.initials: L
authors.lastname: Arce
authors.forename: Miguel
authors.initials: M
authors.lastname: Valcárcel
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006801:Humans; D012463:Saliva / Q000737:chemistry*
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal