Chemiluminescence detection with a regenerable reagent by using tris(2,2'-bipyridyl)ruthenium(II) immobilized in nafion

This research has involved the creation, characterization and application of a regenerable sensor based on electrogenerated chemiluminescence from tris(2,2$\sp\prime$-bipyridyl)ruthenium(II) (or Ru(bpy)$\sb3\sp{2+})$ immobilized within a polymer (Nafion) coated on an electrode. Via control of the electrode potential creation of the reactive reagent Ru(bpy)$\sb3\sp{3+}$ is regulated. The Ru(bpy)$\sb3\sp{3+}$ reacts with analytes to yield chemiluminescence emission with the emission intensity being proportional to the analyte concentration; the reaction results in Ru(bpy)$\sb3\sp{3+}$ being converted to Ru(bpy)$\sb3\sp{2+}$ which is then recycled to Ru(bpy)$\sb3\sp{3+}$ again at the electrode. This sensor has been used in flow-injection analysis to determine oxalate, alkyl tertiary amines and NADH. The respective detection limits for each of these analytes are 1 $\mu$M, 1 nM, and 1$\mu$M. Working ranges for each of these analytes span more than four orders of magnitude. Other species commonly found in biological fluids do not interfere with these determinations. The sensor can be used to quantitate antibiotics possessing amine functionalities. The sensitivity of the system is constant over the wide pH range from 3 to 10. With oxalate, and to a small extent with amines, emission intensities increase with increasing ionic strength and type of cation in solution; this was shown to be a phenomenon related to the Nafion film and not to the chemiluminescence reaction. Temperature studies showed that the emission intensity increases with temperature. Charge studies indicate that oxalate (an anion) does not penetrate the film. Experiments examining the long-term stability of the sensor provided evidence for the existence of multiple phases within the Nafion film. The sensor remains stable for several days using suitable storage conditions. The Nafion film has the ability to store the CL reagent within the film. Studies probing the NADH reaction indicate a reaction stoichiometry of 1 mole of NADH reacting with 2 moles of Ru(bpy)$\sb3\sp{3+}$. Application of this sensor for the chromatographic detection of aliphatic amines after HPLC separation looks promising. The sensor has also been employed for quantitation of oxalate in serum and urine samples.U of I OnlyETDs are only available to UIUC Users without author permissio