Ion-pair ultra-high performance liquid chromatographic analysis of monoamines: peak-splitting at high flow rates.
The use of ion-pair ultra-high performance liquid chromatography (UHPLC) coupled with electrochemical detection (ECD) is of great interest for the fast and sensitive determination of the monoamine neurotransmitters dopamine, noradrenaline and serotonin in microdialysis samples. However, when applying high flow rates in ion-pair UHPLC, other peaks than the initial compound peaks appear on the chromatogram. This peak-splitting phenomenon is caused by disturbed ion-pair retention mechanisms. The influence of several chromatographic parameters is investigated. Peak-splitting is delayed to higher flow rates when increasing the concentration of ion-pair reagent or buffering agent in the mobile phase, when decreasing the percentage of organic modifier in the mobile phase, when applying a stationary phase with a smaller amount of packing material or when increasing the separation temperature. One or a combination of these conditions can be applied to analyze the monoamine neurotransmitters using ion-pair UHPLC-ECD at high flow rates.
Department of Pharmaceutical Chemistry and Drug Analysis, Center for Neurosciences, Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels, Belgium.
Jolien
J
Van Schoors
Hendrik-Jan
HJ
Brouwer
Katrien
K
Maes
Yvette
Y
Michotte
Ann
A
Van Eeckhaut
D015306:Biogenic Monoamines / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007477:Ions; D017551:Microdialysis; D012015:Reference Standards; D012997:Solvents
D015306:Biogenic Monoamines; D007477:Ions; D012997:Solvents
Electrochemical detection; Flow rate; Ion-pair chromatography; Monoamines; Peak-splitting; UHPLC