abstract        background and objective: measurement of amino acids is an important tool for metabolic studies and evaluation of patients’ clinical condition. the aim of this study was to analyze the plasma amino acids using reverse phase high performance liquid chromatography techniques (rp-hplc) with pre-column derivatization by o-phthalaldehyde (opa) in combination with 3- mercaptopropionic...

A selective and sensitive fluorometric determination method for native fluorescent peptides has been developed. This method is based on intramolecular fluorescence resonance energy transfer (FRET) detection in a liquid chromatography (LC) system following precolumn derivatization of the amino groups of tryptophan (Trp)-containing peptides. In this detection process, we monitored the FRET from t...

In this paper, we describe a simple and sensitive method for the selective detection of histidine by combining Tween 20-capped gold nanoparticles (Tween 20-AuNPs) as aminothiol removers and o-phthaldialdehyde (OPA) as the derivatization reagent. We have shown that Tween 20-AuNPs are capable of removing homocysteine (HCys), glutathione (GSH), and gamma-glutamylcysteine (Glu-Cys) at low pH condit...

Simultaneous separation of 37 proteinogenic D/L-amino acids excluding proline with HPLC is generally difficult. In this study, two sets o-phthalaldehyde (OPA)-based fluorescent diastereomers were formed using chiral thiols N-acetyl-L-cysteine (NAC) and N-isobutyryl-L-cysteine (NIBC) independently. It expected that obtained OPA-derivatized D/L show different retention selectivity in reversed pha...

The principle of sequential injection (SI) was exploited to develop a fully automated pre-column derivatization procedure combined on-line to liquid chromatography (LC). Using SI-LC derivatization 14 amino acids were determined fluorimetrically in pharmaceuticals with o-phthaldialdehyde (OPA) as the derivatization reagent. The SI system was used for the handling of samples and reagents, on-line...

We have demonstrated that precolumn derivatization and capillary electrophoresis separation on a poly(dimethylsiloxane) (PDMS) microchip can be realized as efficient as those on glass microchips. In an optimized condition of micellar electrokinetic chromatography (MEKC), using 25 mM sodium borate buffer (pH 10.0) with 25 mM sodium dodecyl sulfate (SDS) and 5% v/v methanol, the electroosmotic fl...

A method for determination of taurine in mouse quadriceps femoris by high performance liquid chromatography with precolumn derivatization ophthalaldehyde (OPA) was established. The sample extracted and treated canon exchange resin. Results showed that separated quantified on C18 reversed phase column chromatographic (HPLC) after OPA 3min, using mixture methanol phosphate （V/V＝1:1，pH＝4.9） as mob...

OBJECTIVES To develop and optimize quantitative HPLC method using 2,3-naphthalenedicarboxaldehyde (NDA) after simple and efficient solid phase extraction to determine the histamine in a biopharmaceutical (Histobulin™). METHODS The HPLC method was established using NDA-induced Histobulin and compared with the recently reported HPLC method using o-phthaldehyde (OPA). The validated NDA-applied H...

Precolumn derivatization and chiral separation of DL-amino acids based on diastereomerization have been performed on an integrated poly(dimethylsiloxane) microchip. Diastereomeric derivatives were formed in a microfabricated precolumn reactor by the reaction of amino acid enantiomers with o-phthaldialdehyde/2,3,4,6-tetra-O-acetyl-1-thio-beta-D-glucopyranose (OPA/TATG), and separated by MEKC in ...