Part I. Gold nanoparticle stabilized acetylcholine esterase enzyme electrode. Part II. A simultaneous TG-DTA study of the thermal decomposition of 2-hydroxybenzoic acid, 2-carboxyphenyl ester (salsalate)

This dissertation consists of two separate parts. Part I: "Gold Nanoparticle Stabilized Acetylcholine Esterase Enzyme Electrode" and Part II: "A Simultaneous TG-DTA Study of the Thermal Decomposition of 2-hydroxybenzoic acid, 2-carboxyphenyl ester (salsalate)".; Part I of this dissertation demonstrates the application of gold nanoparticles to enhance immobilization of AChE on a bulk gold surface electrode. Acetylcholine Esterase (ACNE) is a serine esterase attached to the postsynaptic membrane that rapidly converts the neurotransmitter acetylcholine (ACh) to choline (Ch) and acetate after the transmission of a nerve impulse. As a part of normal cholinergic neurotransmission, the proper functioning of AChE is a critical step. However, it is known that organophosphorus compounds used as chemical warfare agents and pesticides are inhibitors of ACNE and highly neurotoxic leading to cholinergic dysfunction and death. Therefore, simple and sensitive strategies for detecting organophosphorus compounds are critically important.; Electrochemical-based sensors incorporating ACNE have received much attention for the detection of organophosphorus compounds. One challenge, however, for immobilization of enzymes on metal electrode surfaces is the loss of activity that may result. Metal nanoparticles have been shown to aid in the immobilization of enzyme.; The second part of this dissertation demonstrates the application of thermal analysis (TA), gas chromatography and liquid chromatography techniques for investigation of the decomposition mechanism of salsalate.; One major approach to accelerated testing uses thermal analysis methods such as Thermogravimetry (TG) and Differential Thermal Analysis (DTA) to study the thermal decomposition of drugs. The present simultaneous TG-DTA study provides a detailed investigation of the decomposition process of 2-hydroxybenzoic acid, 2-carboxyphenyl ester, known commercially as salsalate. Samples of salsalate were heated in a TG-DTA apparatus in an inert atmosphere (100 mL min -1 nitrogen) in the temperature range 30--500°C. The data indicated that the decomposition of salsalate is a two-stage process. The first decomposition stage (150--250°C) had a best fit with second order kinetics with Ea = 191--198 kJ/mol. The second decomposition stage (300--400°C) is described as a zero-order process with E a = 72--80 kJ/mol. (Abstract shortened by UMI.)...