CAS Number 56-69-9
Molecular Formula C11H12N2O3
Molecular Weight 220.228 g/mol
LogP -1.2
  • 5-Hydroxy-DL-tryptophan
  • 56-69-9
  • 5-hydroxytryptophan
  • DL-5-Hydroxytryptophan
  • 2-amino-3-(5-hydroxy-1H-indol-3-yl)propanoic acid
  • 114-03-4
  • (+-)-5-Hydroxytryptophan
  • DL-Hydroxytryptophan
  • DL-5-HTP
  • 5-Hydroxytryptophan DL-form
  • DL-Pretonine
  • 5-HTP
  • H-DL-Trp(5-OH)-OH
  • Serotonyl
  • Telesol
  • USAF CB-96
  • Tryptophan, 5-hydroxy-
  • HSDB 4295
  • dl-5-Hydroxytryptophane
  • NCI-C56644
  • 5-Hydroxyl-L-tryptophan
  • D,L-5-hydroxytryptophan
  • EINECS 200-284-8
  • 5-Hydroxytryptophan L form
  • BRN 0088199
  • Quietim
  • Oxyfan


HPLC Separation of Polar Compounds

The separation of amino acids, the building blocks of proteins, can be challenging to separate on a reverse-phase column due to their high polarity. Using a mixed-mode HPLC column, allows the separation of amino acids by cation-exchange and ion-exclusion mechanisms as well as hydrophobicity. Fine tuning of separation can be achieved with changes in organic concentration of the mobile phase as well as choice of buffer and pH.


Column Primesep 200, 4.6x150 mm, 5 µm, 100A
Mobile Phase MeCN/H2O
Buffer AcOH, AmFm
Flow Rate 1.0 ml/min
Detection ELSD


Class of Compounds Drug, Acid, Hydrophilic, Ionizable, Hormone
Analyzing Compounds Aspartic acid, Glutaric acid, Glycine, Hydroxytriptophan, GABA, Norepinephrine, Dopamine

Application Analytes:

Aspartic Acid
Glutamic Acid
gamma-Aminobutyric Acid (GABA)

HPLC Separation of Amino Acids in Supplements Composition in Mixed-Mode

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 on Primesep 100 mixed-mode. Retention time is controlled by amount of acetonitrile, buffer and buffer pH. Method does not require ion-pairing reagent. This method is for UV detection. LC/MS, ELSD or Corona CAD can be employed for analysis of amino acids with trifluoroacteic acid or ammonium formate in the mobile phase. This approach can be used for HPLC analysis of all underivatized amino acids.

Application Analytes:

Amino Acids
gamma-Aminobutyric Acid (GABA)