High-performance liquid chromatography of bis[1,2-bis-(diphenylphosphino)ethane]gold(I) chloride, a potential...

The chromatography of [Au(dppe)2]+ (I), a potential antineoplastic drug, was studied on a variety of stationary phases (ODS Hypersil, PLRP-S, Partisil SAX and Partisil SCX) using aqueous mobile phases containing 60% acetonitrile, 15% tetrahydrofuran and various electrolytes. The effects of both the concentration (0-20 mM) and the nature of the electrolytes, added to the mobile phase, on the chromatography of I were investigated. A wide variety of electrolytes were investigated in which the hydrophobicity of both the anion and the cation were varied. The analyte of interest was found to be unretained by the like-charged Partisil SAX column. On the other hand, I was retained on the Partisil SCX by an ion-exchange mechanism and retention could be controlled by manipulating the electrolyte composition of the mobile phase. I was retained on the two reversed-phase materials by a mixture of solvophobic and electrostatic interactions but, under the conditions studied, the latter mechanism was the dominant one. The retention of I on the two reversed-phase materials was influenced much more by the nature and concentration of the cation added to the mobile phase than it was by the nature and concentration of the anion. Therefore, manipulation of the nature and concentration of the cationic species in the mobile phase appears to afford the most useful means of manipulating the retention of I, and presumably its analogues, on reversed-phase columns.