Problems Associated with the Chromatographic Determination of Chlorobenzylgermanium Derivatives Using an Octadecyl Stationary Phase

Abstract

Results of investigations regarding the difficulties of benzylgermanium determination by high performance liquid chromatography using standard octadecyl stationary phases have been substantiated on the molecular level. The analyzed organogermanium compounds are biologically active and some are used in oncology. Investigations showed modifications of the octadecyl stationary phase caused by the above-mentioned derivatives. These modifications have been confirmed by infrared spectroscopy with Fourier transform (FTIR), ¹³C CP/MAS Nuclear Magnetic Resonance techniques (NMR), ²⁹Si CP/MAS NMR, and scanning microscopy. The strongest bonds are formed by benzyltrichlorogermanium but the tribenzyl derivative with a sterically large group and the long, 18-carbon chains, is bound only weakly. It also interacts to the smallest extent with residual silanols of the octadecyl phase. Mass ratio germanium to silica calculated on the base of scanning display after modification was 12.63% for monobenzyl derivative, 12.49%, for dibenzyl, and 5.6% for tribenzyl.

Keywords:

• Benzylgermanium derivatives
• octadecyl stationary phase
• surface modification