Preparative separation of isomeric sulfophthalic acids by conventional and pH-zone-refining counter-current chromatography.
Two modes of high-speed counter-current chromatography (HSCCC) were applied to separate 3- and 4-sulfophthalic acid from a mixture. Conventional HSCCC was useful for the separation of up to several hundred milligram quantities of these positional isomers, while pH-zone-refining CCC was implemented successfully to separations at the multigram level. The conventional HSCCC separations were performed with a standard J-type HSCCC system that has a superior resolution but a lower level of retention of the stationary phase of the biphasic solvent system used (acidified n-butanol-water). The pH-zone-refining CCC separations were performed with an X-type HSCCC system (a cross-axis system) that has a higher capability for retention of the stationary phase. The purified positional isomers (over 99% pure as determined by HPLC) were characterized by 1H NMR and negative ion electrospray ionization mass spectrometry.
Weisz
Adrian
A
aweisz@cfsan.fda.gov
Mazzola
Eugene P
EP
Murphy
Constance M
CM
Ito
Yoichiro
Y
D002851:Chromatography, High Pressure Liquid; D003377:Countercurrent Distribution / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D010795:Phthalic Acids / Q000302:isolation & purification*
D010795:Phthalic Acids