Reversed-phase high-performance liquid chromatography of the stereoisomers of some sweetener peptides with a helical nickel(II) chelate in the mobile phase.
The use of a chiral mobile phase additive in the form of the helically distorted, square-planar, chiral nickel(II) chelate dl-[4,4'-(1-methyl-2-propylethane-1,2-diyldiimino)bis(pent-3 -en-2- onato)]nickel(II) was investigated for the resolution of optical isomers of dipeptide-type sweeteners, viz., aspartame, alitame and antiaspartame, and some of their decomposition products, e.g., diketopiperazines. The chiral discrimination mechanism for the solutes was elucidated. The proposed chiral RP-HPLC system was applied to the stereoselective determination of aspartame impurities in samples of its commercial dietetic and pharmaceutical formulations.
Hygienics Department, Medical University of Lodz, Poland.
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Bazylak
D001218:Aspartame / Q000032:analysis; D002614:Chelating Agents; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D009532:Nickel; D013237:Stereoisomerism; D013549:Sweetening Agents / Q000032:analysis* / Q000737:chemistry
D002614:Chelating Agents; D013549:Sweetening Agents; D009532:Nickel; D001218:Aspartame