Derivatization, stability and chromatographic behavior ofo-phthaldialdehyde amino acid and amine derivatives:o-Phthaldialdehyde/ 2-mercaptoethanol reagent

Abstract

Key WordsColumn liquid chromatography o-Phthaldialdehyde-amino acid and amine derivatives Stability studies and comparisons SummaryA literature overview is given of HPLC methods currently in use to determine amino acids (Ms) and amines (As) as their o-phthalclialdyde (OPA)/2-mercaptoethanol (MCE) derivatives. This is followed by an exhaustive clerivatization study performed using the classical proteinogen Ms, C1 -C4 ahphatic As, several polyamines (PAs) and the OPA/MCE reagent. Model studies have been carried out as a function of reaction time and reagent composition. The primary importance of reagent composition (mole ratios of OPA to SH-group additive) is repeatedly proven. Stabilities of the OPA/MCE derivatives have been compared with corresponding OPA/3-mercaptopropionic acid (MPA) and/or OPA/N-acetyI-L-cysteine (NAC) compounds, obtained under the same conditions.Crucial factors proven to influence the stability of OPA derivatives of Ms and As are discussed in detail: (i) preparation and storage conditions of the OPA reagents, (ii) special behavior of the currently believed to be particularly unstable, Ms and As associated with their original molecular structure, e.g. glycine, 13-alanine, 'y-amino butyric acid (GABA), histicline, ornithine and lysine, several As, as well as (iii) the mole ratios of the OPA/SH-aclditive/M ancl/orA

The effects of grape seed extract fortification on the antioxidant activity and quality attributes of bread

“…The derivatization reagent was composed of 1 mL of OPA stock solution, 8 lL of 2-mercaptoethanol and 3.992 mL borate buffer (consisting of 0.2 M boric acid and 0.2 M NaOH, pH 9.9) (Hanczko & Molnar-Perl, 2003). The reagent was prepared at least 90 min before use for derivatization and was disposed after 2 days.…”

Advancement in the derivatizations of the amino groups with the o-phthaldehyde-thiol and with the 9-fluorenylmethyloxycarbonyl chloride reagents

“…Certainly these two derivatization protocols did have and they still have their uncertainties, limitations, shortages and advantages: however, in the last decade the overwhelming part of uncertainties were examined and cleared up: resulting in the trouble-free, conscious and reliable use the OPA [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] and that of the FMOC [20,21] techniques, as well.…”

Simultaneous analysis of free amino acids and biogenic amines in honey and wine samples using in loop orthophthalaldeyde derivatization procedure

“…The secondary amino acids, proline and hydroxyproline, are not determined as they do not react. Some derivatives are unstable making crucial an appropriate control of the reaction and injection time [47]. Furthermore, this derivatization reagent allows the simultaneous analysis of these compounds without extraction and purification processes preceding the derivatization with fluorescent functional group detection [1,24].…”