The present technology provides liquid quality assessment systems and methods for their preparation and use. The systems can include a light source configured to illuminate a liquid sample, a reflecting surface configured to reflect light scattered by the liquid sample, and a detector configured to detect light intensity, wherein the light source illuminates the liquid sample with a first incident light when the reflecting surface is absent; the detector detects a first light scattered by the liquid sample in response to the first incident light; the light source illuminates the liquid sample with a second incident light when the reflecting surface is present; and the detector detects a second light which is a combination of light scattered by the liquid sample in response to the second incident light and light reflected by the reflecting surface of light scattered by the liquid sample in response to the second incident light.

Provided are a microfluidic biosensors that are suitable for continuously monitoring toxin levels in water supplies.

A method of application to provide a workable solution for tracking the hardness of water utilizing an ion selective electrode by tracking the relative hardness of water at the outflow or egress of an ion exchange column. A monovalent cation exchange membrane (ion selective electrode) distinguishes hard water and softened water in a water flow stream. A voltage is applied across the membrane, facilitating the movement of sodium though the membrane (such that anions and divalent ions are excluded), and the current is measured. The change in current (delta current) is used to determine the hard water concentration or level of hardness in an influent stream. A second application estimates or detects the exhaustion of an ion exchanger, and/or determines the regeneration time/cycle of the ion exchanger through the use of an ion selective membrane. Blending of the influent hard water and effluent soft water allows a user to control hardness levels of the effluent.

An ion exchange membrane separated two electrode flow analyzer for continuous aqueous electrochemical heavy metal detection is disclosed. The electrochemical cell includes a gas diffusion counter/reference electrode, a flooded flow through working electrode, and an ion exchange membrane that separates the gas diffusion counter/reference electrode and the flooded flow through working electrode. A method of continuous fluid analysis using a multi-electrode flow analyzer is also disclosed, including passing an aqueous sample through a first inlet flow area and into a working electrode of a multi-electrode flow analyzer, passing a gas mixture through a second inlet flow area and into a counter/reference electrode of the multi-electrode flow analyzer, depositing an analyte onto a surface of the working electrode, stripping the analyte from the surface of the working electrode by sweeping a range of a potential applied to the surface of the working electrode.

A method may comprise: exposing a substituted chromone dissolved in a solvent to a sample; taking a fluorescence measurement of the sample after exposure to the substituted chromone; and determining a presence or absence of one or more ions in the sample, a concentration of the one or more ions in the sample, or both based on the fluorescence measurement.

A fluorescent nanocomposite which includes a thallium doped gadolinium chalcogenide having formula Tl.sub.xGd.sub.1-xY, wherein x is 0.01 to 0.1, and Y is selected from the group consisting of S, Se, or Te, and a benzothiazolium salt bound to a surface of the thallium doped gadolinium chalcogenide. A method of detecting antimony ions in a fluid sample whereby the fluid sample is contacted with the fluorescent nanocomposite to form a mixture, and a fluorescence emission profile of the mixture is measured to determine a presence or absence of antimony ions in the fluid sample, wherein a reduction in intensity of a fluorescence emissions peak associated with the fluorescent nanocomposite indicates the presence of antimony ions in the fluid sample.

A cartridge assembly, and method of using the same, is provided. The assembly includes a sample processing card and a substrate attached thereto. The card has an injection port for receiving a test sample; at least one metering chamber; a mixing material source for introducing mixing material(s) to the metering chamber; fluid communication channels fluidly connecting the injection port and the mixing material source to the metering chamber; and at least one output port for delivering the test sample to a sensor (e.g., GMR sensor). The substrate has associated therewith: the sensor for sensing analytes in the test sample; electrical contact portions for an electrical connection with a reader unit; and a memory chip. The assembly further includes a pneumatic interface with port(s) and corresponding communication channel(s) fluidly connected to card. The interface connects with an off-board pneumatic system and enables application of positive and negative pressurized fluid to the card to move the test sample and one or more mixing materials therein and to the sensor.

A system for measuring a concentration of lead in water includes a variable electrode having a mixture of lead ionophore II, carbon nanotubes, and a first binder. A reference electrode includes a mixture of carbon nanotubes and a second binder. A meter is electrically connected in series with the variable and reference electrodes, and the meter generates a signal reflective of the concentration of lead in the water when the variable and reference electrodes are immersed in the water. A method for measuring a concentration of lead in water may include preparing a variable electrode having lead ionophore II and a reference electrode having carbon nanotubes. The method may further include electrically connecting a meter with the variable and reference electrodes, immersing the variable and reference electrodes in the water, and generating a signal from the meter reflective of the concentration of lead in the water.

An embodiment provides a method for digesting at least one analyte of an aqueous sample, including: introducing an aqueous sample comprising at least one analyte into a digestion device comprising one or more carbon substituted material electrodes; digesting the at least one analyte by applying an electrical potential between an anode and a cathode of the digestion device, wherein the digesting comprises a step-wise disintegration; measuring the at least one analyte of the aqueous sample from the digested material, using a measurement device selected from the group consisting of: an electrochemical device and an optical measurement device; and modifying the electrical potential based upon the measurement of the at least one analyte. Other aspects are described and claimed.

An embodiment provides a method for measuring an ion component of an aqueous sample using a photoreactive species, including: generating a metal organic framework by combining, in a reactive solution, at least one organic linker and at least one metal; impregnating the metal organic framework with the photoreactive species; introducing the impregnated metal organic framework into an aqueous sample; and measuring an analyte component concentration of the aqueous sample, wherein the measuring comprises measuring a change in the aqueous sample, wherein the change is responsive to the analyte component dissolving at least one of: the at least one organic linker and the at least one metal, and releasing the photoreactive species. Other embodiments are described and claimed.