Electrochemical sensors that utilize enzymes are a sensitive, inexpensive means of detecting biologically relevant analytes. These sensors are further categorized based on their construction and method of signal transport.¹ Type I sensors consist of a crosslinked enzyme on an electrode surface, which are subject to interference from byproducts and other biological analytes. However, type II sensors alleviate this problem with the addition of a redox polymer layer, to assist in signal transportation, thus minimizing interference. There are a growing number of Type II sensors in the literature, however few are commercially available and typically suffer from poor structural and optical characterization.

Previously, an osmium-loaded poly(vinylimidazole) polymer (Os-PVI) was synthesized in order to avoid acetaminophen interference in enzyme sensor testing with successful results, yielding a type II sensor.^{2, 3} Given the success of the polymer, and the potential applications of the polymer for both enzyme and eletrogenerated-chemiluminescent sensors, it was important for Os-PVI to be properly characterized. Using previous literature, the two precursors Os(bpy)₂Cl₂ and poly(vinylimidazole) were synthesized. However, attempts at replication lead to the synthesis of an unknown osmium precursor. When coupled to PVI, a new osmium polymer was synthesized with new fluorescent and redox properties that did not match with the original Os-PVI polymer. All precursors and osmium polymers were characterized with ¹H NMR, fluorescence, mass spectrometry, and cyclic voltammetry in order to provide a better understanding of these compounds and assist in the building of new sensors.

1. Wang, J.; Ju, H.; Zhang, X., Electrochemical Sensors, Biosensors and Their Biomedical Applications. Academic Press: Amsterdam, 2008; Vol. 1st ed.
2. Ohara, T. J.; Rajagopalan, R.; Heller, A., "Wired" Enzyme Electrodes for Amperometric Determination of Glucose or Lactate in the Presence of Interfering Substances. 1994, 66 (15), 2451-2457.
3. Forster, R. J.; Vos, J. G., Synthesis, characterization, and properties of a series of osmium- and ruthenium-containing metallopolymers. Macromolecules 1990, 23 (20), 4372-4377.