Patent Application
20200340963
The patent application did not receive federal research and development funds.
The present invention relates generally to a direct-read device, method and apparatus for protecting against exposure to harmful environments. In this regard, the present invention relates generally to the indication of substance by changing color. The surface wipe and color comparator (SW & CC) of the present invention function by swiping surfaces for target substance, if the wiped surface is contaminated with target substance, a uniform color change appears on the wipe. The intensity of the produced uniform color change is directly proportional to the amount of target substance collected on the wipe. To determine the amount of the collected substance, the uniform color on the wipe is compared to a pre-calibrated color scale on the color comparator. When specific area of surface, i.e. square foot (ft2) or 10 centimeters' square (10 cm2) is wiped, the concentration of substance can be determined; for example, in micrograms/ft2 or micrograms/10 cm2. The color comparator of the present invention includes an arbitrary gray scale to compensate for any dark substance or dirt collect on the wipe.
The need for simple, low cost and real-time qualitative and quantitative detection of trace amounts of toxic substances on surfaces is of great importance to health in the workplace and the environment. Although the current Occupational Safety and Health Administration (OSHA) standards has no surface contamination criteria or quantifications for surface contamination, the standards generally contain housekeeping provisions that address the issue of surface contamination. Exposures to various chemicals are addressed in specific standards for general industry, construction and shipyard employment. OSHA housekeeping provisions are generally the most stringent for the metals, which in solid form may contaminate surfaces and become available for ingestion or inhalation if housekeeping practices are poor. OSHA standards for heavy metals contain provisions stating that “surfaces be maintained as free as practicable of accumulations of the toxic metal” [Code of Federal Regulations (CFR) for Occupational Safety and Health Standards 29 CFR 1910]. Useful guidelines are also provided by the U.S. Department of Energy (DOE), where DOE and its contractors are required to conduct routine surface sampling to determine housekeeping conditions wherever highly toxic and carcinogenic substances such as beryllium and hexavalent chromium [Cr (VI)] are present in operational areas. These criteria, for example, state that for beryllium, the removable contamination level of equipment or item surfaces does not exceed the higher of 0.2 μg/100 cm2 and for Cr (VI), an acceptable surface contamination level of 7.5 μg/100 cm2.
There are numerous devices and methods for collecting and stabilizing the collected samples from surfaces for further laboratory analysis. Avery et al., U.S. Pat. No. 3,450,129 (Jun. 17, 1969) teaches a self-swabbing unit for collection of cultures from body canals and a crushable glass ampoule filled with liquid to stabilize the collected cultures for further laboratory analysis. Several variations of Avery device are described in the literature, including U.S. Pat. Nos. 3,792,699, 3,890,204, 3,890,954, 3,913,564, 4,184,483, 4,311,792, 4,604,360 and 4,770,853. Addleman et al., U.S. Pat. No. 8,943,910 (Feb. 3, 2015) teaches an enhanced swipe sampler with functionalized fibers for collecting explosives and other substances from surfaces.
There are also several devices and methods for direct-read, real-time qualitative (yes/no) detection of toxic substances on surface. Stone, U.S. Pat. No. 5,039,618 (Aug. 13, 1991), U.S. Pat. No. 5,278,075 (Jan. 11, 1994) and U.S. Pat. No. 5,330,917 (Jul. 19, 1994) teaches swabs having a hollow stem and within the hollow stem is one or two cartridges. Crushing the cartridges before swiping surface, a color form if target substance found on surface. Another teaching of Stone, U.S. Pat. No. 5,364,792 (Nov. 15, 1994) where a swab having a hollow stem and within the hollow stem is a cartridge within another cartridge, an activator solution is in one of the cartridges and a reagent is in another of the cartridges. Crushing the cartridges before swiping surface, a color form if target substance found on surface. In all Stone devices, an absorbent ball at the end of the hollow stem is soaked with reagents prior swiping the target surface. A color formed on the soaked ball to indicate qualitative indication of target contaminants. Kirollos et al. US Patent Application No. 20060062689 (Mar. 23, 2006), describes a surface wipe for real-time qualitative detection of toxic substances where a collection media filters dirt to prevent or reduce inaccurate readings and the color change may be viewed through a clear backing. In an effort to quantify the collected substance, a grid work is printed on the clear backing of the wipe, the more cells of the grid that changed in color indicate a more heavily contaminated surface area. Although this device provides general idea about the quantity of collected substance, the irregularity of the color formed in this device make it impossible to accurately determine the quantity of the collected substance. The irregularity of the produced color is due to different pressure applied to the surface. The most intense color produced on the wipe is under the fingers of the person swiping the surface, where most of the pressure applied. The use of the applicator with the wipe can only produce relatively uniform color if the swiped surface is flat and smooth. Pagoria, et al., U.S. Pat. No. 7,829,020 (Nov. 9, 2010) teaches a colorimetric device for the detection of peroxides where a swipe material attached to a polyethylene tube contains two crushable vials with reagents. After swiping a suspected surface, the vials are broken. Peroxides are confirmed by a deep blue color. Genovese, et al., U.S. Pat. No. 9,023,291 (May 5, 2015) teaches colorimetric detection kit comprising a unit containing chemical reagents and a sample collector for collecting a sample analyte from a surface and a separate unit for visualizing a possible reaction of the chemical reagent and sample. Johnson U.S. Pat. No. 9,250,189 (Feb. 2, 2016) teaches a detection kit used for detecting compounds and includes a magnifying lens in a cap that magnifies a surface of a color-changing detection swab when placed on the body of the detection kit.
All the above-mentioned devices and method are intended for; either the collection of substances from surfaces for further laboratory analysis to determine the nature (qualitative) and concentration (quantitative) of target substances on surfaces, or direct-read, colorimetric surface wipes for qualitative (yes/no) detection of substance on surfaces. To our knowledge, there is no direct-read real-time device for qualitative and quantitative determination of substances on surfaces.
There are several color comparators in the literature for testing liquids by comparing the color of the liquid with graduated color standards. Frank, U.S. Pat. No. 3,964,831 (Jun. 22, 1976), teaches a visual color comparator for testing the condition of a liquid and utilizing dual liquid dip cells which are integrally connected. Aronowitz, et al., U.S. Pat. No. 4,877,580 (Oct. 31, 1989) teaches an assay kit comprising an analyte test strip and a color comparator including a plurality of different color fields arranged in an ordered, preferably linear, succession. There is an aperture through each color field so positioned that the reaction zone of the test strip can be placed behind each color field and the color of the reaction zone thereafter viewed through each aperture. Kuzuhara, et al., U.S. Pat. No. 5,972,713 (Oct. 26, 1999) teaches a method for determining total chlorine amount present in a sample and a kit for practicing the method includes the indicator and a color scale for the hues of the dye. There are other color comparators sited in the literature including the following US patents are depicted herein for reference; Peet, U.S. Pat. No. 1,976,672 (October 1934), Frank, U.S. Pat. No. 3,176,577 (April 1965), Rosse et al., U.S. Pat. No. 3,718,439 (February 1973) and Acker et al., U.S. Pat. No. 3,837,745 (September 1974).
It is a general objective of the present invention to provide a reliable and cost-effective device and method for the detection of substances on surfaces.
A primary objective of the present invention is to provide a direct-read device and a method capable of real-time qualitative and quantitative detection of substances on surfaces.
Another object of the present invention is to provide a device capable of the indication of substances by changing color.
Yet another objective of the present invention is to provide a simple means of detecting trace amounts of toxic substances existing on irregular and/or rough surfaces and producing uniform color for quantification.
Another objective of the present invention is to provide a simple means of detecting trace amounts of toxic substances existing on surfaces covered with dirt, soil and/or dark substances.
The present invention is a surface wipe, generally indicated as (100) in figures, for the detection of harmful substances on surfaces by producing uniform color change, and a color comparator to determine the concentration of harmful substance collected on the surface wipe (100) by comparing the intensity and hue of the uniform color on the surface wipe to a calibrated color scale related to specific quantities and/or concentrations of the target harmful substance, the color comparator is generally indicated as (200) in figures, as will be described more fully herein below.
In operation, the surface wipe (100) is held from the handle (130), preferably, using the thumb and index fingers to swipe a suspect surface contaminated by harmful substance. The pressure applied by thumb and index fingers at certain areas on the rigid or flexible top support member (120) during the swiping process is transferred to the flexible body (110). The flexible body of the surface wipe (110) uniformly distribute the pressure applied by fingers throughout its mass and/or take the shape of irregular and uneven surface allowing the collection and color forming assembly (140) to produce uniform color change that can easily and accurately be quantified by the color comparator (200).
The handle (130) is constructed from clear or opaque flexible polyester, polypropylene, polyethylene or any plastic satisfies its intended function of holding the surface wipe (100), preferably, using the thumb and index fingers. The handle (130) is attached or glued to the top support (120).
The top support (120) is constructed from clear or opaque rigid or flexible polyester, polypropylene, polyethylene or any plastic satisfies its intended function of holding the handle (130) to the surface wipe body (110). The top support (120) is attached to the surface wipe body (110) with adhesive or double-sided adhesive tape. The adhesive and the adhesive tape are preferably constructed from silicon, but it can be acrylic or any kind of adhesive that doesn't off-gas any substance that may damage the active ingredient(s) of the collection and color forming assembly (140).
The surface wipe body (110) is constructed from closed or open pores, flexible foam or rubber and functions as a cushion to spread the pressure applied by fingers during the swiping process through its mass. In one embodiment, where the top support (120) is rigid plastic, the pressure applied by fingers during the swiping process is spread uniformly through the surface wipe body (110). In another embodiment, where the top support (120) is flexible plastic, the pressure applied by fingers at certain areas, during the swiping process, causes the top support (120) and the surface wipe body (110) to bend and take the shape of fingers tips, while the surface wipe body (110) functions as a cushion spreading the pressure applied by the fingers throughout its mass. The flexibility of the surface wipe body (110) also functions to take the shape of irregular and rough surfaces allowing the collection and color forming assembly (140) to uniformly swipe the target irregular and rough surfaces. In yet another embodiment, the surface wipe body (110) has a cavity (111) for placing a crushable ampoule (160). The crushable ampoule (160) may contains liquid, such as water or alcohol. In this embodiment, the ampoule is crushed before swiping the surface to wet the collection and color forming assembly (140) to maximize the collection of target substance from the surface. In another embodiment, the crushable ampoule (160) contains a reagent or reagents needed to react with the color forming member (141) before swiping the target surface to allow color formation in case target substance found on surface. In yet another embodiment, the crushable ampoule (160) contains a reagent or reagents needed to react with the color forming member (141) and the target substance after the swing process when the target substance already collected on the collection member (142).
The bottom support (150) is constructed from clear or opaque flexible polyester, polypropylene, polyethylene or any plastic satisfies its intended function of attaching the collection and color forming assembly (140) to the surface wipe body (110). In one embodiment, the bottom support (150) have adhesive or double-sided adhesive tape from both sides to attach the surface wipe body (110) to the collection and color forming assembly (140). The adhesive and double-sided adhesive tape are preferably constructed from silicon, but it can be acrylic or any kind of adhesive that does not off-gas any substance that may damage the active ingredient(s) of the collection and color forming assembly (140). In another embodiment, the bottom support (150) has an opening or perforation (151) to allow the reagent(s) from the crushed ampoule (160) to pass to the collection and color forming assembly (140).
In one embodiment, the collection and color forming assembly (140) is constructed from inert felt, fiber glass or open pores, flexible plastic such as polypropylene and or polyethylene impregnated with reagent or reagents capable of forming color when reacting with target substance. In other embodiment, the impregnated reagents in the collection and color forming assembly (140) are activated by an activating reagent from the crushable ampoule (160) before swiping the target surface. In yet another embodiment, after swiping the target surface, the crushable ampoule (160) is crushed and the released reagent(s) react with the impregnated reagent or reagents in the collection and color forming assembly (140) and the collected target substance to form uniform color change.
In other embodiment of the collection and color forming assembly (140), the collection member (142) is constructed from inert felt, fiber glass or open pores, flexible plastic such as polypropylene and or polyethylene. The color forming member (141) is coated on top of the collection member (142), the side facing the bottom support member (150). The color forming member (141) is constructed from colorimetric reagent(s), porous support(s) and inert binder(s) forming uniform emulsion coated uniformly on top of the collection member (142), the side facing the bottom support member (150).
In one embodiment of the current invention in use, the swiped surface wipe (100) is placed upside-down next to the color scale window (215) on the color comparator (200) as shown in
In one embodiment, the color comparator (200) of the present invention is constructed from first color wheel (240) located under, and coaxial with, first gray scale wheel (220). The coaxial first color wheel (240) and the first gray scale wheel (220) are sandwiched between, and coaxial with, top comparator body (210) and bottom comparator body (250). The top comparator body (210) and bottom comparator body (250) are separated by the comparator insert (230) to allow free rotation and turning of the coaxial first color wheel (240) and the first gray scale wheel (220). The coaxial first color wheel (240) and the first gray scale wheel (220) are separated by first separator (260) having smooth surface from both sides. In use the first separator (260) allows finger, preferably thumb, to smoothly turn the top first gray scale wheel (220) while other finger, preferably index finger, to hold the bottom first color wheel (240) in place. The first separator also allow finger, preferably thumb, to hold top first gray wheel (220) in place while other finger, preferably index, to easily turn bottom first color wheel (240). The axis of the coaxial (210), (220), (240) and (250) can be a screw and nut or rivet (270).
The color wheel (240) has color scale designated to specific concentrations of the target substance. The color wheel can be transparent or opaque. The gray scale wheel (220) is transparent wheel located on top of the color wheel (240) and has arbitrary gray scale to enhance the color matching process and it has no effect in determining the quantity or concentration of the harmful substance collected on the wipe.
Several embodiments of the present invention have been described herein. It should be understood by those of ordinary skill in the art, however, that the above described embodiments, are set forth merely by way of example and should not be interpreted as limiting the scope of the invention. Other alternative embodiments, variations and modifications of the foregoing embodiments that embrace various aspects of the present invention will also be understood upon reading of the detailed description in light of the prior art.
The present invention relates to U.S. Provisional Patent Ser. No. 62/666,135 filed on May 3, 2018 and claims priority therefrom.
