Dopamine

Ultra-Fast HPLC Separation of Underivatized Amino Acids in Reversed-Phase and Cation-Exchange Modes
Application description

Amino acids are essential components of numerous formulation. Health supplements can contain various amino acids and vitamins and require quantitation of each ingredients. Amino acids are very polar compounds with limited or no retention in reversed-phase chromatography. The most common approaches are reversed-phase chromatography with ion-pairing reagent and hydrophilic interaction chromatography (HILIC). Underivatized amino acids can be retained by combination of reversed-phase and cation exchange mechanism. These  two mechanism were combined in Coresep 100 core-shell mixed-mode column. Method can be used for fast analysis of underivatized amino acids without ion-pairing reagent. Depending on the pH of the mobile phase they can exist in acidic, basic or zwitter-ionic form. At lower pH, amino acids are basic in nature and have the highest hydrophobicity. Four amino acids (SER, GLY, ALA, VAL and DOPA) were retained and separated within 2 minutes on core-shell mixed-mode column. This high efficiency separation does not require special UPLC set up and can benefit from core-shell and mixed-mode approaches.

Conditions of Experiment
Column: Coresep 100
Separation Modes: reversed-phase and cation-exchange
Column Dimenstions: 3.2 x 50 mm, 2.7 um, 90A
Mobile Phase: 3% ACN with 0.03% TFA
Detection: UV 210 nm, ELSD
Sample: 0.3 mg/ml
Injection: 10 uL
Flow rate: 1 ml/min
Analytes
Class of compounds: Amino acid, Catecholamine, Drug, Neurotransmitter, Supplement
Nature of compounds: Basic, Hydrophilic, Polar, Zwitterionic
Compounds: Glycine, Alanine, Serine, Valine, Dopamine
Separation of Neurotransmitters on Coresep 100 Column in Reversed-Phase and Cation-Exchange Modes
Application description

Catecholamines (neurotransmitters) are derivatives of the amino acid tyrosine. DOPA, tyrosine, phenylalanine, norepinephrine, epinephrine, and dopamine. Fast and efficient method with base-line separation was achieved on Coresep 100 column. All compounds are separated by combination of reversed-phase and cation-exchange mechanisms. Peak order and retention time can be changed by switching from TFA to ammonium formate in the mobile phase, by adjusting mobile phase composition and by changing pH. The method is fully compatible with mass spectroscopy and can be used for fast analysis of neurotransmitters in biofluids. regular. Method can be used a replacement for analysis of neurotransmitters by UPLC with ion-pairing reagents.

Conditions of Experiment
Column: Coresep 100
Separation Modes: reversed-phase and cation-exchange
Column Dimenstions: 3.2 x 100 mm, 2.7 um, 90A
Mobile Phase: ACN gradient from 5% to 10% in 5 min, buffer gradient - Ammonium formate pH 2.9 from 5 to 25 mM in 5 min
Detection: UV 270 nm, ELSD
Sample: 0.3 mg/ml
Injection: 1 uL
Flow rate: 1 ml/min
Analytes
Class of compounds: Amino acid, Aromatic base, Catecholamine, Drug, Neurotransmitter, Supplement
Nature of compounds: Basic, Hydrophilic, Polar, Zwitterionic
Compounds: Dopamine, Tyrosine, Phenylalanine, Norepinephrine, Epinephrine, DOPA