Analysis of underivatized amino acids and their D/L-enantiomers by sheathless capillary electrophoresis/electrospray ionization mass spectrometry.
Capillary electrophoresis/electrospray ionization-mass spectrometry (CE/ESI-MS) was applied to the analysis of underivatized amino acids and the separation of their D/L-enantiomers. Under full-scan mode, all standard protein amino acids were separated and detected at low-femtomole levels using a 130-cm-long, 20-microm-i.d., 150-microm-o.d. underivatized fused-silica capillary with 1 M formic acid as the background electrolyte. The CE/ESI-MS technique was also applied to the separation of L-arginine from L-canavanine (a close analogue of arginine where the terminal methylene linked to the guanidine group of arginine is replaced by an oxygen atom) in a complex mixture containing all standard protein amino acids. The utility of CE/ESI-MS in the analysis of real-world samples was demonstrated by the identification of two metabolic diseases (PKU and tyrosinemia) through blood analysis with minimal sample preparation. In addition, the on-line separation of 11 underivatized L-amino acids from their D-enantiomers was achieved by using a 30 mM solution of (+)-(18-crown-6)-2,3,11,12-tetracarboxylic acid as the background electrolyte.
Schultz
Casey L
CL
Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA.
Moini
Mehdi
M
D000596:Amino Acids / Q000097:blood*; D001120:Arginine / Q000032:analysis; D002172:Canavanine / Q000032:analysis; D019075:Electrophoresis, Capillary / Q000379:methods*; D006801:Humans; D007231:Infant, Newborn; D010661:Phenylketonurias / Q000175:diagnosis; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013237:Stereoisomerism; D020176:Tyrosinemias / Q000175:diagnosis
D000596:Amino Acids; D002172:Canavanine; D001120:Arginine