On-line concentration and separation of indolamines, catecholamines, and metanephrines in capillary electrophoresis using high concentration of poly(diallyldimethylammonium chloride)

Development and validation of an ultra-high performance liquid chromatography–tandem mass-spectrometry (UHPLC–MS/MS) method for the simultaneous determination of neurotransmitters in rat brain samples

“…Neurotransmitters can be analysed by gas chromatography (GC) (Wood et al, 2006) but a derivatization step is necessary. Therefore, liquid chromatography (LC) (Tsunoda, 2006) or capillary electrophoresis (CE) (Javerfalk-Hoyes et al, 1999;Powell and Ewing, 2005) has been more frequently used, applying electrochemical (Xu et al, 2002;Wang et al, 2008), fluorescence (Yoshida et al, 2007) or UV detection (Tseng et al, 2008). These methods often require a derivatization of the analytes or do not provide enough sensitivity or specificity.…”

Combination of poly(diallyldimethylammonium chloride) and hydroxypropyl-γ-cyclodextrin for high-speed enantioseparation of phenothiazines by capillary electrophoresis

“…The result (Fig. S1, Supplementary material) reveals that the migration time of the three pairs of D,L-phenothiazines progressively decreased with an increase in the PDDAC concentration, which enhanced the reversed EOF [21,22,25]. Monitoring the change in the migration time of mesityl oxide revealed that the reversed EOF increased from 3.9 to 5.5 Â 10 À 4 cm 2 V À 1 s À 1 as the concentration of PDDAC increased from 0 to 1.2%.…”

“…However, two pairs of DL-Pro and DL-Met were not resolved under the same separation conditions. These CE methods for chiral separation of D, a buffer additive for enhancing the separation of positively charged analytes including high-pI proteins [20][21][22] aminothiols [23,24], biogenic amine neurotransmitters [25,26], melamine [27], and pseudomonas quinolones [28]. Because an uncoated capillary exhibits a highly negative charge, analytes of opposite charges are readily adsorbed onto the capillary surface.…”

“…When an uncoated capillary is filled with an aqueous PDDAC solution, electrostatic attraction between PDDAC and the capillary surface creates a monolayer of positively charged PDDAC to suppress the adsorption of cationic analytes and improve their separation efficiency [20]. By contrast, modifying a capillary with PDDAC generates a stable reversed electroosmotic flow (EOF), altering the migration order and improving selectivity [24,25,28]. Therefore, we assumed that the combination of PDDAC and cyclodextrin (CD) derivatives as a buffer additive could enhance the chiral separation of positively charged phenothiazines in CE.…”

Simultaneous quantification of 5-hydroxyindoleacetic acid and 5-hydroxytryptamine by capillary electrophoresis with quantum dot and horseradish peroxidase enhanced chemiluminescence detection

“…In addition, it is regarded as an environmentally friendly technique due to the use of little amount of aqueous separation buffer [16]. CE with laser-induced native fluorescence and UV detection has been applied for simultaneous determination of 5-HT and 5-HIAA [17][18][19][20]. CL detection has been proven to be one of the most sensitive detection technologies [21], there are already a few papers reporting the CE-CL analysis of 5-HT [22,23].…”