ANALYSIS OF NICOTINE AND ITS OXIDATION-PRODUCTS IN NICOTINE CHEWING GUM BY A MOLECULARLY IMPRINTED SOLID-PHASE EXTRACTION

Chromatographic stationary phases showing exceptional selectivity for nicotine can be prepared by the technique of molecular imprinting. Suc h phases were used in the search for a rapid cleanup step for nicotine and some of its oxidation products in chewing gum formulations. Thus, using an organic mobile phase, the nicotine analytes from chewing gum s dissolved in nonpolar solvent were retained, whereas the nonpolar ma trix eluted close to the void peak. A subsequent switch to an acidic m obile phase resulted in elution of the analytes as one sharp peak. Due to weak binding of the less basic oxidation products, other imprinted polymers were tested, and the solid-phase extraction procedure was op timized. Polymers were prepared using various functional and cross-lin king monomers, templates, porogens and thermal treatments. This result ed in phases that, when compared with a nonimprinted or a C18 reversed -phase column, showed significantly higher recoveries of the analytes. Furthermore, no bleeding of template from the phases could be detecte d. The cleanup step was coupled off-line to reversed-phase HPLC, and t he efficiency of the analysis was compared with and without the cleanu p step. Three out of four analytes were quantitatively recovered using the imprinted phase, whereas, using the nonimprinted phase, only nico tine was recovered. Without the cleanup step, none of the analytes cou ld be determined using the reversed-phase HPLC method.