A method for recalibrating an electronic nose includes successively injecting, into a measurement chamber, reference gases that do not contain target compounds and that have various values of relative humidity. A measurement signal is determined in the course of each injection. Then, for each reference gas, a baseline is determined, which baseline is representative of the determined measurement signal. The baseline is also associated with the relative humidity of the reference gas present. A second correction function is determined on the basis of the determined baselines and of the predetermined values of relative humidity. The second correction function is then stored in a processing uni instead of a first correction function.

A smoke detection assembly for indicating when organic material has been smoked in an area includes a decal that has an adhesive layer is integrated such that the decal can be adhered to a surface in a cab of a vehicle. A chemical reagent is provided and the chemical reagent is infused into the decal. The chemical reagent is chemically reactive with one or more chemicals that are unique to smoke from combustion of organic material. Moreover, the chemical reagent changes colors when the chemical reagent is exposed to airborne nicotine. In this way the chemical reagent can visually indicate when organic material has been smoked in the vehicle.

Methods for preserving catalytic activity of a PSA polymer membrane in a humid environment by immobilizing in the membrane an organic acid having a pKa greater than the pKa of the PSA polymer membrane; optical sensors based on the PSA membranes further including an immobilized organic reagent capable of reacting with a target compound in a humid environment to produce a detectable color shifted product; and non-invasive methods for estimating blood glucose concentration by utilizing an optical sensor to detect concentration of acetone in exhaled human breath and correlating it to blood glucose concentration.

A detection device (10), comprising a sample detection layer (1) provided thereon with a detection reagent reacted with an analyte and a result display region (18), wherein the device further comprises a symbol display layer (2) on which an indicator (21) is processed; after the indicator contacts with a gas which can change the color of the indicator, the indicator changes from a first color to a second color.

Methods, apparatuses and systems for providing gas-sensitive substrates are disclosed herein. An example apparatus may comprise: a gas-sensitive substrate at least partially disposed within a gas flow channel of the gas detecting apparatus, wherein at least a portion of the gas-sensitive substrate is treated to mimic stain characteristics produced by at least one interferent gaseous substance, and the gas-sensitive substrate is configured to produce a stain in response to making contact with at least one target gaseous substance disposed within the gas flow channel.

A self-supporting film (10) comprises a gas barrier layer (20); a semi-permeable layer (40); and an indicator material (30), preferably a colorimetric indicator material, is provided between the gas barrier layer (20) and the semi-permeable layer (40). The indicator material (30) is in direct contact with the gas barrier layer (20). The film (10) is particularly useful as an item of packaging, particularly in packaging for perishable materials.

A universal respiratory detector for detecting a respiratory gas. The universal respiratory detector may include a plurality of layers with a visual indicator to quickly and reversibly change color to detect a respiratory gas parameter such as carbon dioxide. The color change may be visible from both sides of the detector. In some examples, the respiratory detector may be a biocompatible and conformable sticker for mounting on a person’s face or an oxygen delivery device.

The present invention provides a chemical sensor comprising a substrate, a first colorimetric sensor array exposed and arranged in a first accommodating space of the substrate and a second colorimetric sensor array arranged in a second accommodating space of the substrate. The second accommodating space is covered with an isolating layer to isolates liquid molecules but allows gas molecules to pass through. The first colorimetric sensor array changes from a first initial color to a first indicating color according to a volatile part and a non-volatile part of an analyte, and the second colorimetric sensor array changes from a second initial color to a second indicating color according to the volatile part of the analyte, so that information of the volatile part and the non-volatile part of the analyte can be obtained simultaneously.

Colorimetric sensors for the detection of contaminants are described herein. In some implementations, the contaminant is formaldehyde. In other implementations, the contaminant is an allergen. Systems and methods for measuring contaminant concentration are also described herein. The colorimetric sensors described herein can be included in or used by disclosed systems and methods. Additionally, the systems and methods described herein can measure the concentration of the contaminant in an indoor environment using the colorimetric sensors.

A rapid testing mechanism for respiratory viral pathogens includes a filter material positioned to capture exhaled breath particles from a respiratory tract. At least a portion of the filter material includes a pathogen binding adsorptive reagent, wherein the pathogen binding adsorptive reagent is a sulfated cellulose membrane. When the exhaled breath particles pass through the filter material, the following occur: when the binding adsorptive reagent reacts, a positive test for respiratory viral pathogens is indicated by the filter material; and when the pathogen binding adsorptive reagent does not react, a negative test for respiratory viral pathogens is individuated by the filter material.