On-line concentration and separation of indolamines, catecholamines, and metanephrines in capillary electrophoresis using high concentration of poly(diallyldimethylammonium chloride).
This paper tackles a simple and efficient method for the simultaneous separation and stacking of neurotransmitters in capillary electrophoresis with UV detection. By using poly(diallyldimethylammonium chloride) (PDDAC) as a buffer additive, the high and reversed EOF are observed. Moreover, the mobility of indolamines and catecholamines decreases as the PDDAC concentration increases. Based on the difference in mobility in the presence and absence of PDDAC, the analytes were simply stacked between the boundary of the sample zone and the background electrolyte containing PDDAC. The separation of 14 analytes including indolamines, catecholamines, and metanephrines was accomplished within 33 min under optimal conditions (1.2% PDDAC and 5 mM formic acid at pH 4.0), and the values of relative standard deviation of their migration time were less than 3.1%. By applying stacking methods for fourteen analytes, we observed: (a) the sample injection volume of sample is up to 216 nL, (b) the limits of detection at signal-to-noise of 3 range from 15.4 to 122.1 nM, and (c) the sensitivity enhancements, compared to normal injection (12 nL), range from 110- to 220-fold. Under the optimal stacking conditions, the present method has been applied to analyze of vanillomandelic acid, 5-hydroxyindole-3-acetic acid, dopamine, tryptamine, and 3-indoxyl sulfate in urine samples.
Tseng
Wei-Lung
WL
Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan.
Chen
Sheng-Min
SM
Hsu
Chih-Yao
CY
Hsieh
Ming-Mu
MM
D000328:Adult; D002395:Catecholamines / Q000302:isolation & purification*; D002849:Chromatography, Gas; D002851:Chromatography, High Pressure Liquid; D019075:Electrophoresis, Capillary; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007211:Indoles / Q000302:isolation & purification*; D008297:Male; D008676:Metanephrine / Q000302:isolation & purification*; D011095:Polyethylenes / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012996:Solutions; D014466:Ultraviolet Rays; D014556:Urine / Q000737:chemistry
D002395:Catecholamines; D007211:Indoles; D011095:Polyethylenes; D000644:Quaternary Ammonium Compounds; D012996:Solutions; C041004:poly-N,N-dimethyl-N,N-diallylammonium chloride; D008676:Metanephrine; C067042:indolamine