New triazine spectroscopic reagent for the separation of DL-amino acids by micellar electrokinetic chromatography.
An approach to the chiral separation of racemic mixtures of amino acids by means of micellar electrokinetic chromatography after derivatization with a new triazine spectroscopic reagent, 3-(4,6-dichloro-1,3,5-triazinylamino)-7-dimethylamino-2-methylphenazine (DTDP), has been evaluated. It was found that the derivatives of the aliphatic amino acids such as serine, valine and arginine, could produce a strong UV absorption at 282 nm, whose apparent molar absorptivities are of 10(-4) M(-1) cm(-1), and thus the concentration of the amino acids down to 3 x 10(-7) M can still give a detectable signal (S/N = 3). Beta-Cyclodextrin (beta-CD) added to the buffer system was used as a chiral selector, and separation conditions were optimized. The presence of an organic modifier (2-propanol) was also a prerequisite for the chiral separation. The best results for the chiral separation of DTDP-amino acids were achieved in a mixed sodium dodecylsulfate-beta-CD-borate-2-propanol medium at pH 9.0. Compared to some of the commonly used derivatization methods, the present one offers a relatively stable derivative and strong UV absorption for the spectroscopically inert amino acids, thus enabling amino acids to be separated and detected by CE even with a simpler UV detector.
Ma
Hui-Min
HM
Center for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Beijing. mahm@infoc3.icas.ac.cn
Wang
Zhi-Hua
ZH
Su
Mei-Hong
MH
D000596:Amino Acids / Q000302:isolation & purification*; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D003505:Cyclodextrins / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents / Q000737:chemistry*; D012680:Sensitivity and Specificity; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D014227:Triazines / Q000737:chemistry*; D047392:beta-Cyclodextrins
D000596:Amino Acids; D003505:Cyclodextrins; D007202:Indicators and Reagents; D014227:Triazines; D047392:beta-Cyclodextrins; D012967:Sodium Dodecyl Sulfate; C031215:betadex