Aiming to a smart agriculture through the electrochemical impedance of a chitosan-molybdate membrane as a function of available phosphate species.

Identifying and quantifying accessible nutrients in the soil are critical in agriculture since plants require particular amounts of micro and macronutrients to grow successfully. However, there is no well-defined method for quantifying macronutrients in the field at present. In this work, chitosan and chitosan-molybdate membranes were deposited onto stainless steel (SS) and carbon (C) substrates and evaluated as promising candidates for the quantification of phosphorous species available in cultivated soil. The membranes were morphologically and structurally studied by atomic force microscopy and infrared spectroscopy to determine their appearance, roughness, and chemical conformation. Electrochemical impedance spectroscopy was the electrochemical tool used to evaluate the quantification capacity of phosphorus species of the membrane-based electrodes; it was found that the chitosan-molybdate membranes deposited onto the SS/C interface presented the best performance when the electrodes change in charge transfer resistance and chemical capacitance were measured as a function of the concentration of phosphorus species available in a synthetic sample. Thus, based on the presented results, chitosan biosensors have shown the capability of attracting ionic species, which contributes to the minimization of preference zones on the surface of a sensing electrode. [ABSTRACT FROM AUTHOR]