Search

fast and accurate micellar electrokinetic capillary chromatography (MEKC) method was developed for monitoring N-methyl-2-pyrrolidone (NMP) exposure. Baseline separation of NMP and its main metabolites: 5-hydroxy- N-methyl-2-pyrrolidone (5HNMP), N-methylsuccinimide (MSI), 2-hydroxy- N-methylsuccinimide (2HMSI), and 2-pyrrolidone (2P) was obtained within 6 min in an uncoated fused silica capillary using 5 mM phosphate buffer and 140 mM sodium dodecyl sulfate (pH 7.1) as background electrolyte (BGE). On-line UV-detection was performed at 200 nm and the applied electric field was 400 V cm. Possible interference of BGE-induced system peaks on separation was investigated by computer simulation and no such interference was observed. The developed MEKC method combined with solid phase extraction for sample preparation was successfully applied to the analysis of urine of rats exposed to NMP. The urinary excretion was determined in 0-6 h and 6-24 h specimens collected after an intragastic administration of 308 mg NMP / kg rat body weight. The results of NMP disposition kinetics in rat urine are reported for NMP and metabolites. [InlineMediaObject not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The behavior of seven hydroxy anthraquinone derivatives was studied by capillary zone electrophoresis and micellar electrokinetic chromatography. The effects of buffer pH (6.5-10.8) and sodium dodecyl sulfate concentration (10-20 mmol L-1) on the effective mobilities of the analytes and their separation were tested. A comparison of the two optimized separation systems showed that micellar electrokinetic chromatography was superior as it permits separation of all the seven analytes within 15 min, using 15 mmol L-1 sodium dodecyl sulfate in 10 mmol L-1 tetraborate buffer, pH 8.5, at a voltage of 20 kV. The calibration curves were linear in the concentration range from 5.0 · 10-7 to 5.0 · 10-4 mol L-1 for most of the analytes, at a detection wavelength of 254 nm. LOD and LOQ values of the analytes were in the ranges of 2.10 · 10-7-1.28 · 10-6 mol L-1and 6.99 · 10-7-4.25 · 10-6 mol L-1, respectively. The proposed separation conditions were applied to determination of 1,2-dihydroxy anthraquinone (alizarin) and 1,2,4-trihydroxy anthraquinone (purpurin) in Rubia tinctorum aglycone and of the recently described 1-acetyl-2,4,5,7-tetrahydroxy-9,10-anthraquinone and 1-acetyl-2,4,5,7,8-pentahydroxy-9,10-anthraquinone in the mycelium of fungi Geosmithia lavendula. [ABSTRACT FROM AUTHOR]