Systems, methods, and devices for testing gaseous samples for concentrations of specific chemicals. An apparatus has two sensing assemblies for testing for hydrogen sulfide concentrations in gaseous samples. A first assembly is disposed to expose a first side of a sensing tape to a first stream of a gaseous sample. A second assembly is disposed to expose a second side of the same sensing tape to a second stream of another gaseous sample. Both assemblies detect and analyze the hydrogen sulfide concentrations of their respective gaseous samples by way of their respective sides of the sensing tape.

The following description relates to a composite for a harmful material-detecting sensor, which includes a dye having a color-change function by reaction with acid or base and a polymer material, a method for producing the composite for the harmful material-detecting sensor, and a low-cost film-type color change harmful material sensor, which includes the composite for the harmful material-detecting sensor so as to quickly detect a harmful material and can be carried by an individual.

Provided herein is technology relating to detecting gaseous analytes and particularly, but not exclusively, to devices and methods related to detecting gaseous analytes by monitoring changes in liquid crystals upon exposure to the gaseous analytes.

A test element (10) used to determine concentration levels of free and total chlorine in a water sample comprises a test pad (12) adhered to a substrate (14), wherein the test pad (12) is impregnated with a stabilized DPD solution. The test pad (12) is color responsive to different concentration levels of chlorine in the water and compared to a color chart to determine the level of free chlorine and/or total chlorine in the water. The stabilized DPD solution may include N,N-diethyl-p-phenylenediamine oxalate salt, a polymeric anhydride such as a methyl-vinyl anhydride and an organo-sulfate such as dimethylsulfone.

A hydrogen sulfide test kit includes a first reactant powder that includes citric acid, a second reactant powder that includes sodium bicarbonate, and a test paper that changes color upon contact with hydrogen sulfide. The first and second reactant powders are physically separated from each other. A method of using the hydrogen sulfide test kit and a method for detecting hydrogen sulfide in an aqueous sample bot include allowing the citric acid and the sodium bicarbonate to react in the aqueous sample to form air bubbles that release any hydrogen sulfide in the aqueous sample into gas form; contacting the released hydrogen sulfide in gas form, if present, with the test paper; and detecting the presence of hydrogen sulfide in the aqueous sample based on the color of the test paper.

A tamper-indicating device, the tamper-indicating device including: an elongate structure; a penetrant chamber coupled to the elongate structure; and a physical barrier (or other release mechanism) disposed between the elongate structure and the penetrant chamber; wherein the penetrant chamber is adapted to contain a penetrant material that selectively diffuses into the elongate structure at a predetermined rate when the physical barrier is ruptured (or the other release mechanism is actuated) by a tamper or environmental event; and wherein the penetrant material creates an overt or covert indication of the degree of diffusion into the elongate structure, the degree of diffusion indicating an amount of time since the tamper or environmental event. The tamper-indicating device further includes a substrate coupled to the elongate structure. Optionally, the tamper-indicating device further includes a visible time scale disposed on the substrate substantially adjacent to the elongate structure.

An analytical process for detecting compounds in a sample suspected of containing a peroxide-based compound, a nitrate-based compound, a nitrotoluene-based compound, or a nitramine-based compound includes treating the sample with a superbase and then contacting the sample with a composition. The composition includes or consists of a Ni-porphyrin and an acid and optionally an acid stable solvent.

An embodiment provides a method for measuring ozone in a sample, including: introducing at least one alkene to a sample, wherein the alkene in the presence of an amount of ozone produces a carbonyl solution; adding 3-methyl-2-benzothiazolinonehydrazone hydrochloride (MBTH) to the carbonyl solution, and thereafter adding an oxidant to produce at least one imine and oxidized MBTH; producing a conjugated indicator from a reaction of the at least one imine and the oxidized MBTH; and measuring, using a colorimetric technique, an amount of ozone. Other aspects are described and claimed.

Systems and methods are provided for tracking all chemicals, including odors, a package is exposed to throughout the shipping process. A device is attached to the package or placed within the package to extract the chemicals that are in the surrounding environment to the device. The device can extract and concentrate volatile, semi-volatile and non-volatile chemicals that the device and the corresponding package are exposed to throughout the shipping process. The extracted chemicals may then be desorbed from the device and analyzed by an analytical instrumentation method.

Provided is an optical detection chip that makes it possible to accurately measure, in a short time, hydrogen sulfide and methyl mercaptan contained in a gas subject to detection. An optical detection chip is provided with: an optically transparent substrate; and a layer structure provided with a pigment layer that is formed on the optically transparent substrate, that includes organic pigment molecules containing amino groups, ketone groups, or quinones, as well as metal ions of at least one kind selected from the group consisting of Mn, Fe, Co, Ni, Cu, Zn, Cd, Hg, Ag, Pb, and Tl, and that exhibits a color change in response to a gas subject to detection including at least one of hydrogen sulfide and methyl mercaptan.