Abstract: Embodiments of the invention provide self-contained phosphate sensors with an analyte-specific reagent and a pH-modifier. The analyte-specific reagent includes a molybdenum salt or metal complex and a dye. The self-contained phosphate sensors can be used either in aqueous or non-aqueous solution or as a solid-state device. These self-contained phosphate sensors require no post-addition reagents to determine phosphate concentrations and the phosphate determination test requires a reduced number of procedural steps. Moreover, the self-contained phosphate sensor provides enhanced sensitivity and faster response time. Embodiments of the invention also provide a method for determining phosphate concentrations in a sample. The phosphate concentration in a sample can be quantified using a calibration curve generated by testing samples with known phosphate concentrations.

Abstract: A method of quantitatively measuring the concentration of a chemical species in a sample solution with a sensor film. A hydrogel sensor film is prepared having a chemical composition comprising an indicator that changes its optical property in the ultra-violet, visible or near-infrared spectral range upon being exposed to the chemical species in the sample solution. The film is exposed to a fixed amount of the sample solution. The concentration of the chemical species in the sample solution is quantified using the average absorbance measured from the sensor film.

Abstract: A system that includes a device is provided in which the device includes a piezoelectric substrate; a sensor layer disposed on the substrate and operable to interact with, or react with, a target species; a first and a second electrode that are spaced from each other and in communication with the substrate; a first detector operable to detect the interaction or the reaction of the sensor layer with the target species based on a change in an optical characteristic of electromagnetic radiation propagated through the substrate; and a second detector operable to acoustically detect the interaction or the reaction of the sensor layer with the target species. Associated methods are provided.

Abstract: A device that includes a piezoelectric substrate is provided. The device may include a sensor layer disposed on the substrate and operable to interact with, or react with, a target species; a first and a second electrode, that are spaced from each other and in communication with the substrate; a first detector operable to detect the interaction or the reaction of the sensor layer with the target species based on a change in an optical characteristic of electromagnetic radiation propagated through the substrate; and a second detector operable to acoustically detect the interaction or the reaction of the sensor layer with the target species. Associated methods are provided.