Metal oxide nanomaterial-modified ion-selective electrodes for detection of NH4+ in aquaponic systems: electrochemical analyses, characterization, and sensing mechanism
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引用次数: 0
Abstract
Potentiometric NH4+ sensors were developed by modification of ion-selective electrodes with different metal oxide nanomaterials forming solid-contact layers, including titania (TiO2), manganese dioxide (MnO2), and stannic oxide (SnO2). A potentiometric method was used to determine the basic analytical parameters of the sensors. Furthermore, electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV), and water layer tests were used to evaluate the electrochemical features of the electrodes. The results for the modified metal oxides and unmodified electrodes were compared, and the effectiveness of each material as a solid-contact layer on the electrode was evaluated. The best results were found for an electrode with a solid-contact layer of SnO2 nanomaterial (GCE/SnO2/NH4+-ISM). The GCE/SnO2/NH4+-ISM electrode displayed a selective and fast response to NH4+ ions (4.8 s) during the potential measurements. In this case, a slope of 47.17 mV/decade (R = 0.99), a linearity range of 1 × 10−7–1 × 10−2 M, and a limit of detection of 1.18 × 10−8 M were obtained. This electrode exhibited good reproducibility, a high potential response, and stability, making it an attractive alternative for the development of effective SC-ISEs to detect NH4+ in aquaponic nutrient solutions.
期刊介绍:
Ionics is publishing original results in the fields of science and technology of ionic motion. This includes theoretical, experimental and practical work on electrolytes, electrode, ionic/electronic interfaces, ionic transport aspects of corrosion, galvanic cells, e.g. for thermodynamic and kinetic studies, batteries, fuel cells, sensors and electrochromics. Fast solid ionic conductors are presently providing new opportunities in view of several advantages, in addition to conventional liquid electrolytes.