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Determination of pharmaceuticals in plasma by capillary electrophoresis without sample pretreatment reproducibility, limit of quantitation and limit of detection
Author(s) -
Kunkel Annette,
Günter Stefan,
Wätzig Hermann
Publication year - 1997
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.1150181026
Subject(s) - detection limit , chromatography , chemistry , sodium dodecyl sulfate , capillary electrophoresis , micellar electrokinetic chromatography , salicylic acid , hydrofluoric acid , reproducibility , analyte , acetonitrile , analytical chemistry (journal) , biochemistry , organic chemistry
Abstract Pharmaceuticals in human plasma are determined on underivatized fused‐silica capillaries by micellar electrokinetic capillary chromatography (MEKC) without sample pretreatment. Our best method to date uses as running buffer a sodium dodecyl sulfate (SDS) containing borate buffer (60 m M with 200 m M SDS) at pH 10. Between runs, proteins adsorbed to the capillary wall are removed by an acetonitrile and SDS‐buffer rinsing regimen (50% v/v each). A day‐to‐day precision for relative peak areas of about 2% relative standard deviation (RSD; n >40) has been reached. Different rinsing approaches are discussed (salts, enzyme‐containing solutions, organic solvents, hydrofluoric acid). The separation system is tested in a concentration range between approximately 100 mg/L‐10 mg/L. Correlations between the limit of quantitation, the limit of detection and the signal/noise are discussed. The applicability of the system is demonstrated for the pharmaceuticals acetaminophen, salicylic acid, sulfamethoxazole, tolbutamide, and trimethoprim.