Enantioseparation of N-fluorenylmethoxycarbonyl alpha-amino acids on polysaccharide-derived chiral stationary phases by reverse mode liquid chromatography.
The enantioseparation of N-protected fluorenylmethoxycarbonyl (N-FMOC) alpha-amino acids was carried out on three polysaccharide-derived chiral stationary phases, such as cellulose tris(3,5-dimethylphenylcarbamate) (Chiralcel OD), amylose tris(3,5-dimethyl-phenylcarbamate) (Chiralpak AD) and cellulose tris(4-methylbenzoate) (Chiralcel OJ), and the influence of acetonitrile composition and pH of the eluents on the enantioseparation in reverse mode chromatography was examined. The best separation of the enantiomers was achieved with 40% acetonitrile in 50mM phosphate buffer at pH 2. However, increasing the composition of acetonitrile to 50% on Chiralcel OD yielded a considerable decrease of retention time with minimum loss of resolution. The elution order of N-FMOC alpha-amino acid enantiomers on Chiralcel OD and OJ were quite different, indicating that both phases could be used in a complementary manner for the separation of the enantiomers of N-FMOC alpha-amino acids. The positive relationship between the capacity factor of N-FMOC alpha-amino acids and the hydrophobicity of amino acids indicated that hydrophobicity plays an important role on the retention of the N-FMOC alpha-amino acids in the reverse mode.
Lee
Kyung-Ah
KA
College of Pharmacy, Chungnam National University, Daejeon 305-764, Republic of Korea.
Yeo
Sujeong
S
Kim
Kyeong Ho
KH
Lee
Wonjae
W
Kang
Jong Seong
JS
D000097:Acetonitriles / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry / Q000302:isolation & purification*; D000688:Amylose / Q000031:analogs & derivatives* / Q000737:chemistry; D001565:Benzoates / Q000737:chemistry*; D002021:Buffers; D002482:Cellulose / Q000031:analogs & derivatives* / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D005449:Fluorenes / Q000737:chemistry / Q000302:isolation & purification*; D006863:Hydrogen-Ion Concentration; D057927:Hydrophobic and Hydrophilic Interactions; D048448:Phenylcarbamates / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry; D013237:Stereoisomerism
D000097:Acetonitriles; D000596:Amino Acids; D001565:Benzoates; D002021:Buffers; D005449:Fluorenes; C016456:N(alpha)-fluorenylmethyloxycarbonylamino acids; D048448:Phenylcarbamates; D012997:Solvents; C090722:tris(4-methylbenzoate)cellulose; C065943:cellulose tris-3,5-dimethylphenyl-carbamate; C080033:Chiralpak AD; D002482:Cellulose; D000688:Amylose; C032159:acetonitrile