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Determination of metabolic organic acids in cerebrospinal fluid by microchip electrophoresis
Author(s) -
Danč Ladislav,
Bodor Róbert,
Troška Peter,
Horčičiak Michal,
Masár Marián
Publication year - 2014
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.201300455
Subject(s) - chemistry , oxalic acid , chromatography , chloride , electrophoresis , thermal conductivity detector , conductivity , cerebrospinal fluid , citric acid , propane , gas chromatography , inorganic chemistry , organic chemistry , medicine , pathology
A new MCE method for the determination of oxalic, citric, glycolic, lactic, and 2‐ and 3‐hydroxybutyric acids, indicators of some metabolic and neurological diseases, in cerebrospinal fluid (CSF) was developed. MCE separations were performed on a PMMA microchip with coupled channels at lower pH (5.5) to prevent proteins interference. A double charged counter‐ion, BIS‐TRIS propane, was very effective in resolving the studied organic acids. The limits of detection (S/N = 3) ranging from 0.1 to 1.6 μM were obtained with the aid of contact conductivity detector implemented directly on the microchip. RSDs for migration time and peak area of organic acids in artificial and CSF samples were <0.8 and <9.7%, respectively. Recoveries of organic acids in untreated CSF samples on the microchip varied from 91 to 104%. Elimination of chloride interference, a major anionic constituent of CSF, has been reached by two approaches: (i) the use of coupled channels microchip in a column switching mode when approximately 97–99% of chloride was removed electrophoretically in the first separation channel and (ii) the implementation of micro‐SPE with silver‐form resin prior to the MCE analysis, which selectively removed chloride from undeproteinized CSF samples.