title: Determination of peptides and amino acids from wool and beer with sensitive fluorescent reagent 2-(9-carbazole)-ethyl chloroformate by reverse phase high-performance liquid chromotography and liquid chromotography mass spectrometry.
abstract: A new method for the sensitive determination of amino acids and peptides using the tagging reagent 2-(9-carbazole)-ethyl chloroformate (CEOC) with fluorescence (FL) detection has been developed. Identification of derivatives was carried out by liquid chromotography mass spectrometry. The chromophore in the 2-(9-fluorenyl)-ethyl chloroformate (FMOC) reagent was replaced by carbazole, which resulted in a sensitive fluorescence lerivatizing agent CEOC. CEOC can easily and quickly label peptides and amino acids. Derivatives are stable enough to be efficiently analyzed by high-performance liquid chromatography. Studies on derivatization demonstrate excellent derivative yields over the pH range 8.8-10.0. Maximal yields close to 100% are observed with three- to fourfold molar reagent excess. Derivatives exhibit strong fluorescence and allow direct injection of the reaction mixture with no significant disturbance from the major fluorescent reagent degradation by-products, such as 2-(9-carbazole)-ethanol and bis-(2-(9-carbazole)-ethyl) carbonate. In addition, the detection responses for CEOC derivatives are compared to those obtained with FMOC. The ratios AC(CEOC)/AC(FMOC) = 1.00-1.82 for fluorescence (FL) response and AC'(CEOC)/AC'(FMOC) = 1.00-1.21 for ultraviolet (UV) response are observed (here, AC and AC' are, respectively, FL and UV response). Separation of the derivatized peptides and amino acids has been optimized on a Hypersil BDS C18 column. Excellent linear responses are observed. This method was used successfully to analyze protein hydrolysates from wool and from direct-derivatized beer.
authors.affiliation: Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 161 Zhongshan Road, Dalian 116011, China.
authors.forename: Jinmao
authors.initials: J
authors.lastname: You
authors.forename: Yichu
authors.initials: Y
authors.lastname: Shan
authors.forename: Liang
authors.initials: L
authors.lastname: Zhen
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Yukui
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D000818:Animals; D001515:Beer / Q000032:analysis*; D002227:Carbazoles / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D013058:Mass Spectrometry; D010455:Peptides / Q000032:analysis*; D014935:Wool / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D002227:Carbazoles; D010455:Peptides