title: Ethyl propiolate as a post-column derivatization reagent for thiols: development of a green liquid chromatographic method for the determination of glutathione in vegetables.
abstract: The present study reports the development, validation and application of a new green liquid chromatographic method for the determination of glutathione (GSH) in vegetable samples. In this work we introduce-for the first time-ethyl propiolate (EP) as an advantageous post-column derivatization reagent for thiolic compounds. GSH (t(R)=6.60 min) and N-acetylcysteine (NAC, internal standard) (t(R)=11.80 min) were separated efficiently from matrix endogenous compounds by using a 100% aqueous mobile phase (0.1%, v/v CH(3)COOH in 1 mmol L(-1) EDTA, Q(V)=0.5 mL min(-1)) and a Prevail(®) reversed phase column that offers the advantage of stable packing material in aqueous mobile phases. The parameters of the post-column reaction (pH, amount concentration of the reagent, flow rates, length of the reaction coil and temperature) were studied. The linear determination range for GSH was 1-200 μmol L(-1) and the LOD was 0.1 μmol L(-1) (S/N=3). Total endogenous GSH was determined in broccoli, potato, asparagus and Brussels sprouts using the standards addition approach. The accuracy was evaluated by both recovery experiments (R=91-110%) and comparison to an o-phthalaldehyde/glycine corroborative post-column derivatization fluorimetric method.
authors.affiliation: Laboratory of Analytical Chemistry, Department of Chemistry, Aristotelian University of Thessaloniki, GR-54124 Thessaloniki, Greece.
authors.forename: Constantinos K
authors.initials: CK
authors.lastname: Zacharis
authors.forename: Paraskevas D
authors.initials: PD
authors.lastname: Tzanavaras
authors.forename: Anastasia
authors.initials: A
authors.lastname: Zotou
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005978:Glutathione / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D011422:Propionates / Q000737:chemistry*; D013050:Spectrometry, Fluorescence / Q000379:methods; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D014675:Vegetables / Q000737:chemistry*
chemical_list: D000480:Alkynes; D011422:Propionates; D013438:Sulfhydryl Compounds; D005978:Glutathione; C544697:ethyl propiolate