Determination of 1-methylhistidine and 3-methylhistidine by capillary and chip electrophoresis with contactless conductivity detection.
CE with capacitively coupled contactless detection (C4D) was used to determine 3-methylhistidine (3-MH) and 1-methylhistidine (1-MH). The C4D response to 3-MH was studied in a BGE consisting of 500 mM acetic acid and ammonia at varying concentration and the results were compared with the theory. Complete separation of a model mixture of 3-MH, 1-MH, and histidine (His) was attained in two optimized BGEs, one containing 500 mM HAc, 20 mM NH4OH, and 0.1 % m/v hydroxyethylcellulose (HEC), pH 3.4 (I) and the other consisting of 100 mM morpholinoethanesulfonic acid (MES), 25 mM LiOH, and 0.1 % m/v HEC, pH 5.5 (II). These optimized BGEs were tested in CE/C4D analyses of urine. Promising results were obtained for separation and determination of 3-MH, 1-MH, and His on a silicon microchip, using aluminum strips as the C4D electrodes; the three analytes were baseline-separated within less than 30 s with a separation channel effective length of 38 mm. The LOD were satisfactory and amounted to 26.4 microM for 3-MH and 18.3 microM for 1-MH.
Tůma
Petr
P
Institute of Biochemistry, Cell and Molecular Biology, 3rd Faculty of Medicine, Charles University, Prague, Czech Republic. petr.tuma@lf3.cuni.cz
Samcová
Eva
E
Opekar
Frantisek
F
Jurka
Vlastimil
V
Stulík
Karel
K
D004553:Electric Conductivity; D019075:Electrophoresis, Capillary / Q000379:methods*; D046209:Electrophoresis, Microchip / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008762:Methylhistidines / Q000032:analysis* / Q000652:urine
D008762:Methylhistidines; C028120:1-methylhistidine; C028118:3-methylhistidine