A sensor for the detection of lead includes a substrate, a working electrode formed on a surface of the substrate, a counter electrode formed on the surface of the substrate, a dielectric layer covering a portion of the working electrode and counter electrode and defining an aperture exposing other portions of the working electrode and counter electrode. The working electrode includes a metalized film with working surface and a monolayer (or bilayer) of bismuth deposited on the working surface by underpotential deposition.

Certain embodiments include a sensor system for measuring chlorine concentration in water. The sensor system can have a manifold including one or more flow passages for receiving fluid flow. The sensor system can have a probe for measuring chlorine concentration in fluid communication with a flow passage of the one or more flow passages of the manifold. The probe can have a probe body oriented to direct incoming fluid from one or more flow passages of the manifold toward an end of the probe body. The probe can have a plurality of flutes defined on an outer surface of the probe body. The flutes can be shaped and oriented to direct fluid from the end proximal to the electrodes, back toward the one or more flow passages of the manifold.

The present invention discloses novel multi-action copper complexes which are used for reversible vapochromic detection of polar solvents as well as anion sensing in both aqueous and non-aqueous media.

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An aspect provides a method of determining a concentration of free chlorine in an aqueous sample, including adding a reagent to the sample, the reagent being reactive with the free chlorine at a first kinetic rate and reactive with at least one chloramine at a second kinetic rate, the first kinetic rate being different from the second kinetic rate; measuring an absorbance response over time resulting from reaction of the free chlorine and the at least one chloramine with the reagent over time; and determining the concentration of the free chlorine in the sample based on a determined rate of change of the absorbance response over time. Other aspects are described and claimed.

Method and compositions using transition metal salts and/or ammonium chloride to liberate toxins and other molecules from cyanobacteria, useful for assaying for total cyanobacterial toxins in lakes, reservoirs and other waters.

The present invention relates to a water sampling immersion probe (50) for continuously filtering a water sample from wastewater (14). The water sampling immersion probe (50) includes a distal coarse filter (60) with a porosity of 0.1 to 1.0 mm, a proximal fine filter (70) arranged downstream of the coarse filter (60) and having a porosity of less than 5.0 μm, and a sample suction opening (74) arranged downstream of the fine filter (70). The coarse filter (60) is arranged to not contact the fine filter (70).

A water quality measuring system includes a first introduction section for introducing rearing water as a sampling target, and a first adding section which adds an acid to the rearing water introduced by the first introduction section, and a nitrous acid sensor whose measurement target is nitrous acid and which measures the measurement target concentration of the rearing water to which the acid has been added by the first adding section. The water quality measuring system includes a second adding section which adds a base to the rearing water introduced by the first introduction section, and an ammonia sensor whose measurement target is ammonia and which measures the measurement target concentration of the rearing water to which the base has been added by the second adding section.

An embodiment provides a method, including: operating a motor to position sample fluid within a fluid channel of a cuvette; transmitting light through an optical chamber of the cuvette; measuring a value of received light that has been transmitted through the optical chamber; comparing the measured value of light to one or more thresholds; determining a position of the sample fluid within the fluid channel based on a comparison from the comparing step; and generating a response based upon the position of the sample fluid with the fluid channel. Other aspects are described and claimed.

An apparatus for accurately measuring carbon dioxide partial pressure even if the apparatus is disposed in an environment at a high ambient water pressure, such as in a deep sea environment. A through hole that penetrates a body portion is formed in the body portion. The body portion is connected to a light source unit and a light receiving element unit. A signal line is disposed to pass through the through hole formed in the body portion. The signal line electrically connects between an amplifier substrate of the light receiving element unit and a CPU substrate of the light source unit to transfer the detection result amplified by the amplifier substrate.

A chemical measurement device for determining the concentration of given chemical in a given fluid has at least one LED light source and at least one light detector. The given chemical has a light absorption curve with a peak, and the at least one LED light source and at least one light detector are configured to collaborate to produce two light signals having peak wavelengths between about 5 nm and 35 nm apart. The two light signal peak wavelengths are in the ultraviolet region with wavelengths beyond the light absorption curve peak. The light signal peak wavelengths, however, also are before the light absorption curve is negligible. The device also has a concentration calculator operatively coupled with the at least one light detector. The concentration calculator is configured to compare the two light signals to produce a concentration signal representing the concentration of the given chemical in the given fluid.