Determination of amino acids by capillary electrophoresis-electrospray ionization-mass spectrometry: an evaluation of different protein hydrolysis procedures.
In this work, a CE equipment, online hyphenated to an IT MS analyzer by a linear sheath liquid interface promoting ESI, was used to develop a method for quantitative determination of amino acids. Under appropriate conditions (BGE composition, 0.8% HCOOH, 20% CH3OH; sheath liquid composition, 0.8% HCOOH, 60% methanol; V ESI, +4.50 kV), analytical curves of all amino acids from 3 to 80 mg/L were recorded presenting acceptable linearity (r >0.99). LODs in the range of 16-172 micromol/L were obtained. BSA, a model protein, was submitted to different hydrolysis procedures (classical acid and basic, and catalyzed by the H+ form of a cation exchanger resin) and its amino acid profiles determined. In general, the resin-mediated hydrolysis yields were overall similar or better than those obtained by classical acid or basic hydrolysis. The resulting experimental-to-theoretical BSA concentration ratios served as correction factors for the quantitation of amino acids in Brazil nut resin generated hydrolysates.
Simionato
Ana V Colnaghi
AV
Institute of Chemistry, University of São Paulo, São Paulo, Brazil. avsimionato@pq.cnpq.br
Moraes
Edgar Perin
EP
Carrilho
Emanuel
E
Tavares
Marina Franco Maggi
MF
Kenndler
Ernst
E
D000596:Amino Acids / Q000032:analysis* / Q000592:standards; D000818:Animals; D002417:Cattle; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007475:Ion Exchange Resins; D009754:Nuts / Q000737:chemistry; D011506:Proteins / Q000737:chemistry*; D012015:Reference Standards; D012710:Serum Albumin, Bovine / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data
D000596:Amino Acids; D007475:Ion Exchange Resins; D011506:Proteins; D012710:Serum Albumin, Bovine