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COLORIMETRIC SENSOR BASED ON SILVER NANOPARTICLES FOR THE DETERMINATION OF VOLATILE SULFUR COMPOUNDS
WO18015607
Volatile sulfur compounds such as hydrogen sulfide, methyl mercaptan and dimethyl sulfide are toxic gases, harmful to the environment and health. For the determination of volatile sulfur compounds in situ and in real time, one possibility is to use active sampling techniques such as commercial colorimetric tubes, but they require an external source of energy. Regarding passive sensors, few options exist for detecting volatile sulfur compounds because some drawbacks such as excessively high detection limits, low reproducibility or the toxicity of the reagents employed. Researchers at the University of Valencia have developed a passive colorimetric sensor for in situ detection of volatile sulfur compounds with detection limits of 45 ppb, making it suitable to use in the detection of sulfur compounds in real atmospheres. The sensor is passive so does not need any pretreatment, or power supply or external instrument. The sensor is further characterized by its safety to the environment, its stability against a wide range of temperatures and to humidity and solar radiation, and its resistance to reversion, so that the sensor response is stable over time.
Applications: The sensor developed is applicable as method of point of needed for the detection of bad breath that may be associated with periodontitis or gingivitis and environmental control systems for the detection of hydrogen sulfide in critical locations (wastewater treatment plants, landfills, drains, pipes, oil processing, etc.). Advantages: The main advantages provided by the invention are: - Simplicity and ease of use: it is a passive colorimetric sensor that does not require any kind of pretreatment or power supply or external instrument. - Low cost: simple fabrication process without high costs. - Low detection limits: of the order of 45 ppb v/v. - Quantitative detection: direct quantitative detection can be carried out by diffuse reflectance of the sensors. - Stability: the sensor remains stable for a period of 3 months. Reversion resistance. - In situ and in real time monitoring: the response of the sensor is obtained in just 10 minutes. - Portability: small device with a smartphone for signal recording. - On-site analysis: It allows sample analysis at the point of care (POC) or point of need (PON) without sample treatment. - Connectivity: digital analytical signal processing with remote storage and transmission options.