Interlaboratory reproducibility of mobility parameters in capillary electrophoresis for substance identification in systematic toxicological analysis.
An interlaboratory pilot study was performed to determine the reproducibility of mobility parameters in capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC). The study was performed by an intended small number of laboratories (three) that used different brands of instruments (two). The effective mobility was corrected using standards by a method that was recently introduced to obtain a more reproducible migration parameter. A test set of 20 acidic test compounds and 5 reference compounds were analyzed during five days in each laboratory using CZE and MEKC. Buffers used consisted of 90 mM borate set at pH 8.4 (CZE) and 20 mM phosphate, 50 mM sodium dodecyl sulfate set at pH 7.5 (MEKC). Analyses were carried out using fused-silica capillaries at an electric field strength of either 52.6 kV/m or 37.5 kV/m. The interlaboratory reproducibility (mean RSD) of the effective mobility was 3.0% for CZE and 6.7% for MEKC. After applying the correction method, these values became 3.0% for CZE and 3.3% for MEKC, which is adequate for systematic toxicological analysis (STA) applications. A significant improvement of reproducibility for the calculated corrected effective mobility mu(eff)c was observed when variations are high. Therefore, it is recommended to use the correction method in interlaboratory situations, especially when instruments and capillaries from different manufacturers are used.
Boone
Carolien M
CM
Department of Analytical Chemistry and Toxicology, University Center for Pharmacy, Groningen, The Netherlands. c.m.boone@farm.rug.nl
Manetto
Giulia
G
Tagliaro
Franco
F
Waterval
Joop C M
JC
Underberg
Willy J M
WJ
Franke
Jan-Piet
JP
de Zeeuw
Rokus A
RA
Ensing
Kees
K
D002138:Calibration; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000295:instrumentation / Q000592:standards; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000592:standards*; D015588:Observer Variation; D004364:Pharmaceutical Preparations / Q000032:analysis* / Q000592:standards; D010865:Pilot Projects; D012015:Reference Standards; D014116:Toxicology / Q000295:instrumentation / Q000379:methods* / Q000592:standards
D004364:Pharmaceutical Preparations