A molecularly imprinted receptor for separation of testosterone and epitestosterone, based on a steroidal cross-linker

A series of molecularly imprinted polymers have been prepared and investigated as stationary phases in high performance liquid chromatography for the separation of testosterone and epitestosterone using non-polar mobile phases. The polymers were imprinted using 5 alpha-dihydrotestosterone as template, and all retain testosterone more strongly than its 17 alpha-OH epimer. The best polymer was prepared using trifluoromethylacrylic acid as functional monomer (interacting with the template via hydrogen bonds), divinylbenzene as 'inert' cross-linker, and chloroform as porogen. It also included a steroid-based crosslinker, which may interact with the template via van der Waals interactions to lend additional 'shape selectivity'. A 250 x 4.6 mm column packed with this polymer gave baseline resolution of testosterone and epitestosterone (15 mu g each) in under 20 min. Preparation of the steroid based cross-linker included the selective reduction of 5 alpha-dihydrotestosterone (17 beta-hydroxy-5 alpha-androstan-3-one) to the 3 alpha,17 beta-diol using K-selectride. (C) 2011 Elsevier Inc. All rights reserved.