Native fluorescence detection methods and detectors for naphthalene and/or other volatile organic compound vapors

Inventors

Hug, William F. • Bhartia, Rohit • Reid, Ray D. • Lane, Arthur L.

Assignees

Photon Systems Inc

Abstract

Naphthalene, benzene, toluene, xylene, and other volatile organic compounds have been identified as serious health hazards. This is especially true for personnel working with JP8 jet fuel and other fuels containing naphthalene as well as other hazardous volatile organic compounds (VOCs). Embodiments of the invention are directed to methods and apparatus for near-real-time in-situ detection and accumulated dose measurement of exposure to naphthalene vapor and other hazardous gaseous VOCs. The methods and apparatus employ excitation of fluorophors native or endogenous to compounds of interest using light sources emitting in the ultraviolet below 300 nm and measurement of native fluorescence emissions in distinct wavebands above the excitation wavelength. The apparatus of some embodiments are cell-phone-sized sensor/dosimeter “badges” to be worn by personnel potentially exposed to naphthalene or other hazardous VOCs. The badge sensor of some embodiments provides both real time detection and data logging of exposure to naphthalene or other VOCs of interest from which both instantaneous and accumulated dose can be determined. The badges employ a new native fluorescence based detection method to identify and differentiate VOCs. The particular focus of some embodiments are the detection and identification of naphthalene while other embodiments are directed to detection and identification of other VOCs like aromatic hydrocarbons such as benzene, toluene, and xylene.

Core Innovation

The invention is an in situ method for repeatedly sensing volatile organic compounds (VOCs) in the surrounding atmospheric environment using a sample chamber, where a specific VOC, or combination of VOCs of interest, enters while in a vapor state and is located at a sample location for measurement. The method provides repeated collection and repeated removal by varying the temperature of the sample location, thereby refreshing the sample location in preparation for subsequent VOC collection.

Excitation radiation is provided onto the sample location with a wavelength in the ultraviolet range, while the sample location has a temperature different from ambient temperature. Native fluorescence emission radiation arising from the excitation radiation is received onto at least one optical element that directs the fluorescence radiation along at least one detection path, and native fluorescence emission is detected at at least one location along the detection path.

The detected native fluorescence emission is used to determine whether it corresponds to a VOC of interest. The method refreshes the sample location and repeats receiving, detecting, and determining a plurality of times to provide updated information on the presence of the VOC or VOCs of interest in the surrounding atmospheric environment.

Claims Coverage

The provided set includes one independent claim, which describes the core repeatedly sensing method. The inventive features below summarize the main elements of that independent claim; dependent claim refinements are not enumerated because the relevant main inventive features are already captured in the independent claim text.

Across the single independent claim, the method repeatedly refreshes a temperature-varying sample location, excites the sample with ultraviolet radiation at a non-ambient temperature, detects native fluorescence along directed detection paths, determines correspondence to a VOC of interest, and repeats cycles to update the presence information.

Stated Advantages

Documented Applications