Determination of nonsteroidal anti-inflammatory drugs in biological fluids by automatic on-line integration of solid-phase extraction and capillary electrophoresis.
A new, automatic method for the clean-up, preconcentration, separation, and quantitation of nonsteroidal anti-inflammatory drugs (NSAIDs) in biological samples (human urine and serum) using solid-phase extraction coupled on-line to capillary electrophoresis is proposed. Automatic pretreatment is carried out by using a continuous flow system operating simultaneously with the capillary electrophoresis equipment, to which it is linked via a laboratory-made mechanical arm. This integrated system is controlled by an electronic interface governed via a program developed in GWBasic. Capillary electrophoresis is conducted by using a separation buffer consisting of 20 mM NaHPO4, 20 mM beta-cyclodextrin and 50 mM SDS at pH 9.0, an applied potential of 20 kV and a temperature of 20 degrees C. The analysis time is 10 min and the detection limits were between 0.88 and 1.71 microg mL(-1). Automatic clean-up and preconcentration is accomplished by using a C-18 minicolumn and 75% methanol as eluent. The limit of detection of NSAIDs can be up to 400-fold improved when using sample clean-up. The extraction efficiency for these compounds is between 71.1 and 109.7 microg mL(-1) (RSD 2.0-7.7%) for urine samples and from 77.2 to 107.1 microg mL(-1) (RSD 3.5-7.1%) for serum samples.
Analytical Chemistry Division, University of Córdoba, Spain.
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D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000097:blood / Q000302:isolation & purification* / Q000652:urine; D001331:Automation; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006801:Humans; D007052:Ibuprofen / Q000097:blood / Q000302:isolation & purification / Q000652:urine; D007213:Indomethacin / Q000097:blood / Q000302:isolation & purification / Q000652:urine; D007660:Ketoprofen / Q000097:blood / Q000302:isolation & purification / Q000652:urine; D010654:Phenylbutyrates / Q000097:blood / Q000302:isolation & purification / Q000652:urine; D014046:Tolmetin / Q000097:blood / Q000302:isolation & purification / Q000652:urine
D000894:Anti-Inflammatory Agents, Non-Steroidal; D010654:Phenylbutyrates; D007660:Ketoprofen; C010725:fenbufen; D014046:Tolmetin; D007052:Ibuprofen; D007213:Indomethacin