Compositions, devices and processes related to etching of a very thin layer or fine particles of a metal are disclosed for monitoring a variety of parameters, such as time, temperature, time-temperature, thawing, freezing, microwave, humidity, ionizing radiation, sterilization and chemicals. These devices have capabilities of producing a long and sharp induction period of an irreversible visual change. The devices are composed of an indicator comprising a very thin layer of a metal and an activator, e.g., a reactant, such as water, water vapor, an acid, a base, oxidizing agent or their precursors, which is capable of reacting with the said indicator. Ink formulations composed of a metal powder and a proper activator can be used for monitoring several sterilization processes, such as sterilization with steam. When water is used as an activator, a thin layer of metals, such as that of aluminum can be used as steam sterilization or humidity indicator.

Provided are a method and system for measuring hydrogen peroxide concentration in sample water collected from a prescribed position in a water treatment process and includes: collecting the sample water; measuring a concentration of a dissolved oxygen in the sample water or a treated water obtained by treating the sample water with the hydrogen peroxide decomposing device by first and second dissolved oxygen concentration measuring analyzers to obtain a corrected value that is a difference between the two dissolved oxygen concentration values; measuring the concentration of the dissolved oxygen in the sample and treated water by the first and second dissolved oxygen concentration measuring analyzers, respectively, and obtaining a measured value that is a difference between the dissolved oxygen concentration values; and calculating a corrected concentration of hydrogen peroxide from the measured value obtained during the measured value obtaining and the corrected value obtained during the corrected value obtaining.

The present invention provides a method for the rapid monitoring of biological analytes in a point-of-care setting by providing a smart phone; providing a sample chamber; providing a sample; providing a dark box with a smartphone holder attached to the dark box top with the camera opening positioned about the aperture, adding a biological specimen suspected of containing a biological analyte in the sample chamber; adding a bis(2,4,6-trichlorophenyl) oxalate, an imidazole and a fluorophore to the sample chamber to react with the biological analyte; placing the sample chamber into the dark box; generating an emission from the fluorophore in response to the reaction with the biological analyte; and recording a set of time-lapse images of the emission with the smartphone.

An optical sensing element for use in the detection of hydrogen peroxide, the sensing element comprising a sensing compound provided as a coating on a substrate. The sensing compound, on exposure to hydrogen peroxide, forms a luminescent reporter compound when excited with stimulating radiation at a predetermined wavelength that the sensing compound does not absorb.

A method is provided for suppressing, in a color reagent solution which is used to measure a component within a sample and which contains an oxidative color reagent dissolved therein, a background rise that occurs when the color reagent solution is stored. The method includes adjusting a hydrogen ion exponent (pH) of the color reagent solution so as to be strongly acidic. The hydrogen ion exponent is preferably adjusted to 2.9 or below or to 2.1 or below. The color reagent solution is preferably used to measure the degree of oxidative stress. The oxidative color reagent is preferably a phenylenediamine derivative.

Peracid stable fluorescent active compounds in highly acidic, equilibrium peroxycarboxylic acid sanitizing compositions are disclosed as having improved fluorescent stability allowing for monitoring of peroxycarboxylic acid concentration by conductivity and/or optical sensors. Beneficially, the compositions are also low odor and low/no VOC dual functioning acid wash and sanitizing compositions.

The present invention provides a method for the rapid monitoring of biological analytes in a point-of-care setting by providing a smart phone; providing a sample chamber; providing a sample; providing a dark box with a smartphone holder attached to the dark box top with the camera opening positioned about the aperture, adding a biological specimen suspected of containing a biological analyte in the sample chamber; adding a bis(2,4,6-trichlorophenyl) oxalate, an imidazole and a fluorophore to the sample chamber to react with the biological analyte; placing the sample chamber into the dark box; generating an emission from the fluorophore in response to the reaction with the biological analyte; and recording a set of time-lapse images of the emission with the smartphone.

The invention relates to the use of nanoparticles of at least one oxide of at least one transition metal doped with a rare earth element, particularly Y.sub.xVO.sub.4Eu.sub.1-x nanoparticles obtained through a sol-gel process, as a sensitive material in a chemical sensor for detecting peroxide-compound vapors. The material is used in a liquid process, in a spray of the initial sol, or in a solid thin film after being deposited on a substrate. The inorganic, fluorescent character of the nanoparticles makes it possible to obtain a sensitive material for an optical sensor that has good performance stability over time. The intended uses are the detection of explosives or explosive precursors, particularly peroxides, the control or monitoring of atmospheric pollution and ambient-air quality, and the monitoring of industrial sites.

Disclosed herein are equipment-free flow-through assay devices based on patterned porous media, methods of making same, and methods of using same. The porous, hydrophilic media are patterned with hydrophobic barriers for performing assays on liquids.

The present invention provides a method for the rapid monitoring of biological analytes in a point-of-care setting by providing a smart phone; providing a sample chamber; providing a sample; providing a dark box with a smartphone holder attached to the dark box top with the camera opening positioned about the aperture, adding a biological specimen suspected of containing a biological analyte in the sample chamber; adding a bis(2,4,6-trichlorophenyl) oxalate, an imidazole and a fluorophore to the sample chamber to react with the biological analyte; placing the sample chamber into the dark box; generating an emission from the fluorophore in response to the reaction with the biological analyte; and recording a set of time-lapse images of the emission with the smartphone.