Disclosed is a method for detecting a metal ion in an aqueous solution, the method comprising immersing a hydrogel in the aqueous solution, wherein the hydrogel comprises a prefluorescent imaging moiety that is activated upon binding the metal ion. The method enables detection of lead ions in water.

An embodiment provides a method for measuring mercury in a solution, including: preparing a thiocarbamate-based indicator; introducing the thiocarbamate-based indicator to a solution, wherein the solution contains an amount of mercury and the introducing causes a change in fluorescence of the solution; and measuring the amount of mercury in the solution by measuring a change in intensity of the fluorescence. Other aspects are described and claimed.

The object of the present invention is to provide a novel flow analysis method and a novel flow analyzer each of which makes it possible to improve accuracy of an analysis. A flow analysis method in accordance with an embodiment of the present invention attains the above object by including: a sample introducing step of introducing a sample into a tube (100); a reagent adding step of adding a reagent to the sample which is transferred through the tube (100); and an analyzing step of quantitatively or qualitatively analyzing the sample to which the reagent has been added and further including, after the reagent adding step and before the analyzing step, a gas-liquid separating step of sequentially removing gas which is present in the tube (100).

A disposable screen-printed microchip based on an organic membrane sensitive layer is presented. The microchip is highly responsive for the determination of Lead(II). The microchip is composed of a composite sensitive material which comprises carbon nano-tubes “CNTs” and titanium (IV) oxide nano-particles embedded in a PVC membrane which was deposited on the surface of a plastic screen printed micro-electrode using a new methodology. The prepared disposable microchip provides a linear response for Pb2+ ions covering the concentration range of 1×10.sup.−6 to 1×10.sup.−1 mole L.sup.−1 with high sensitivity (49 mV), a long life span (>4 months) and short response time (10 s). The merits offered by the micro-sensor or microchip include small size, simple fabrication, mass production, integration feasibility and cost effectiveness and automation.

There is described a fiber-optic sensor for measuring a light signal from a fluorescible sample comprising heavy metal ions, for example. The fiber-optic sensor comprises an optical fiber having a side surface by which the light signal from the fluorescible sample is inputted. The optical fiber is corrugated to form at least two gratings on the side surface of the optical fiber. Each grating comprises periodically longitudinally spaced-apart valleys on the surface of the optical fiber, and is longitudinally spaced apart from any other grating of the at least two gratings.

A device for measuring pH levels and contaminant concentration includes an electrode assembly that is electrically coupled to a control unit. The electrode assembly includes a FLUID first contact electrically coupled to a reference electrode, a second contact electrically coupled to a working electrode, and a third contact electrically coupled to a counter electrode. The working electrode may be modified to include a cysteine functionalized graphene oxide with polypyrrole nanocomposite. In operation, the control unit may apply a complex signal to the working electrode via the second contact in order to adhere and subsequently strip contaminant ions from the fluid sample to the working electrode. During this process, a current may be measured across the reference electrode and the counter electrode to measure contaminant ion concentration. The pH of the fluid sample may also be determined by a current measured across the reference electrode and the counter electrode. In some examples, the pH may be used to calibrate the measured levels of the contaminant ions.

One embodiment provides a pipe inspection robot, including: a chassis configured to traverse through an interior of a water or sewer pipe; a water quality probe comprising a first end that couples to the chassis and a sensing end distal thereto; an electric motor configured to reposition the sensing end of the water quality probe with respect to the chassis; said electric motor acting to move the sensing end of the water quality probe to reposition the sensing end proximate to fluid containing water located proximate to a bottom part of the chassis; the sensing end configured to contact the fluid containing water for contact sensing of water quality data. Other aspects are described and claimed.

The mercury detecting paper provides a visual indication of the presence of mercury in an applied water sample. The mercury detecting paper is formed as a hydrophobic substrate having a reagent layer deposited thereon. The hydrophobic substrate is made from paper having a layer of hexamethyldisilazane (HMDS) deposited thereon, and the reagent layer is a layer of 6-hydroxy-3-(2-oxoindolin-3-ylideneamino)-2-thioxo-2H-1,3-thiazin-4(3H)-one (HOTT). In use, a water sample is applied to the reagent layer and a visual color change of the reagent layer upon contact with the water sample indicates a presence of mercury in the water sample. Specifically, HOTT turns a brick red color upon contact with Hg.sup.2+ ions.

Composites comprising metal-oxide-functionalized carbon nanotubes with metal nanoparticles deposited thereon are provided. These composites can be used as a working electrode in an electrochemical sensor to detect arsenite in aqueous solutions. The composite can electrochemically reduce As.sup.3+ to As.sup.0 due to increasing adsorption capability. In one embodiment, Au nanoparticles are deposited on the TiOx/CNT electrode to facilitate the adsorption of As.sup.3+ on the electrode surface for further electrochemical reduction process. Square wave voltammetry (SWV) is performed to detect the electrochemical reduction of arsenite in water.

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