Apparatus and method evaluating quantitative permeation of toxic material through a specimen
Patent Information
- Authority / Receiving Office
- IN · IN
- Patent Type
- Patents
- Current Assignee / Owner
- DIRECTOR GENERAL DEFENCE RES & DEV ORG
- Filing Date
- 2021-12-24
- Publication Date
- 2026-07-16
Abstract
Description
FIELD OF THE INVENTIONThe present disclosure relates to a system and a method for evaluating quantitative permeation of toxic material through a specimen.BACKGROUNDChemhazard suit is a category of protective clothing used to protect the wearer from dangerous chemicals like chemical warfare agents (CWA) used in asymmetric war. Further, in order to test the ability of the chemhazard suit to protect the wearer from exposure to the chemicals, various tests are devised. Conventionally, a test specimen, called a swatch, made of the same material as the chemhazard suit is used to perform the test. A number of methodologies exist for the measurement of permeation of toxic chemicals especially CWA or their simulants including U.S. Army Test Operating Procedures (TOP) 08-2-501 and 08-2-503. TOP 08-2-501 specifies the apparatus and protocols for permeation measurements depending upon configuration and permeation modes. The configuration of permeation is based on the physical state of chemicals in challenged / contamination and permeated conditions.Generally, there are three main configurations; liquid contamination vapor detection (L / V) configuration, vapor contamination vapor detection (V / V) configuration and liquid contamination liquid detection (L / L) configuration.According to TOP 08-2-501, in L / V and V / V configurations, a stream of dry air is passed to sweep the permeated contamination to the sorbent tube consisting of sorbent material. Permeation density is quantified using chemical agent monitors (CAM) or by desorption of sorbent material available in sorbent tubes / bubblers placed at the outlet in the lower body of test cell followed byquantification using chromatographic / spectroscopic technique. The stream of dry air at ambient temperature may not be able to vaporise permeated toxic material completely especially in the case of low volatile CWA, e.g., VX, and thus the accuracy of the method becomes poor. In TOP 08-2-501, the evaluation methods of materials using L / L configuration with expulsion mode, inverted expulsion mode and mandrel mode are also described, where permeation is qualitatively evaluated under stress or under tension and breakthrough time is measured contrary to the permeated density of chemical agent.Further, the TOP 08-2-503 provides the standard methods for testing the permeation of low volatility chemicals, such as persistent nerve agents e.g., VX, through swatches of protective materials in L / L configuration. According to TOP 08-2-503, a sorbent disc is used adjacent underneath of contaminated protective material test sample to adsorb the permeated quantity of toxic material in liquid form. The method is described for the quantitative expulsion mode where permeation is evaluated under stress to mimic the realistic scenario where the wearer of the protective ensemble touches the contaminated surface or holds a contaminated object. Permeation density is calculated by extraction of contamination from sorbent disc placed adjacent underneath of sample swatch as per the test standard TOP 08-2-503 followed by evaluation using a chromatographic / spectroscopic technique.Permeation evaluation of protective materials in L / L configuration is important as permeation of toxic chemicals, especially CWA in liquid form is most hazardous due to high penetration through the skin of the individual. In TOP 08-2-501 and TOP 08-2-503, apparatus and methods for the quantitative permeation evaluation of protective materials in L / L configuration under normal conditions (without stress) are not described. In addition, the use of sorbent disc in TOP 08-2-503, makes the method cost-ineffective. The efficiency of sorbent disc may differ from the efficiency of sorbent material in granular form, therefore there is the involvement of additional steps in evaluating the efficiency of sorbent disc.In both, the TOPS, apparatus and methodologies are described where a larger size of sample swatch is used (exposed area 10 cm2) and accordingly a large amount of toxic chemical, especially CWA is also required to maintain the prescribed contamination density (10 g / m2).Therefore, there exists a need for a simple and effective quantitative permeation evaluation for L / L configuration for swatch.SUMMARYThis summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention. This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.The present subject matter relates to aspects of performing evaluation of permeation of a toxic material through a specimen. The technique of the present disclosure allows for quantitative evaluation of permeation of toxic chemical in liquid form through a specimen.In an embodiment, an apparatus for measuring permeation of toxic chemicals on a specimen is disclosed. The apparatus includes a first cell body and a second cell body defining an airtight chamber there between and adapted to receive the specimen. The apparatus includes a first cap attached to the first cell body and adapted to supply a predetermined volume of the toxic chemical to the chamber on a first side of the specimen. The apparatus also includes a second cap attached to the second cell body and adapted to supply a sorbent to the chamber on a second side of the specimen. Further, a degree of permeation is measured as determine a degree of contamination the sorbent by the toxic material quantitatively.In another embodiment, a method of measuring permeation of a toxic chemical through a specimen. The method includes placing a specimen in an airtight chamber of an apparatus and placing a predetermined volume of sorbent in a cavity proximate to a second side of the specimen. The method also includes supplying a predetermined volume of toxic material to a first side of the specimen. In addition, the method includes holding the arrangement of the toxic material and the sorbent with respect to the specimen for a predetermined period of time. Finally, the method includes performing quantitative analysis to determine a degree of contamination the sorbent by the toxic material to determine a volume of toxic material in the sorbent upon the lapse of predetermined period of time. In one example, the volume of the toxic material in the sorbent is indicative of the degree of permeation of the toxic chemical on the specimen.The technique of the present disclosure enables quantitative evaluation of permeation which was not possible in previously known L / L configuration. Moreover, performing the test in an airtight chamber prevent vaporisation of the toxic material thereby enabling quantitative evaluation of the permeation. In addition, quantitative permeation of the liquid toxic chemical allows for better measure of the ability of the material to absorb the toxic material.To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.BRIEF DESCRIPTION OF THE DRAWINGSThese and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:Figure 1 illustrates an exploded view of an apparatus to measure permeation of a toxic chemical through a specimen in L / L configurations for static-diffusion flow mode, according to an embodiment of the present disclosure;Figure 2 illustrates an exploded view of the apparatus to measure permeation of a toxic chemical through the specimen having a first polytetrafluoroethylene (PTFE) layer, according to an embodiment of the present disclosure;Figure 3 illustrates an exploded view of the apparatus to measure permeation of a toxic chemical through the specimen having a second polytetrafluoroethylene (PTFE) layer, according to an embodiment of the present disclosure;Figure 4 illustrates an exploded view of the apparatus to measure permeation of a toxic chemical through the specimen having a ring of colorimetric paper, according to an embodiment of the present disclosure;Figure 5 illustrates a method for measuring the permeation of the toxic chemical through a specimen, according to an embodiment of the present disclosure;Figure 6 shows a Table 1 indicating test conditions of quantitative permeation test in L / L configuration, according to an embodiment of the present disclosure;Figure 7 shows a Table 2 indicating specifications of three-layered composites of two specimen material namely activated carbon sphere (ACS) based three layered composite and activated carbon fabric (ACF) based three layered composite, according to an embodiment of the present disclosure; andFigure 8 shows results of the permeation test conducted using the apparatus of Figure 1 by implementing the method of Figure 5, according to an embodiment of the present disclosure.Further, skilled artisans will appreciate that elements in the drawings are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the drawings by conventional symbols, and the drawings may show only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the drawings with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.DETAILED DESCRIPTION OF FIGURESFor the purpose of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated system, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skilled in the art to which this invention belongs. The system, methods, and examples provided herein are illustrative only and not intended to be limiting.For example, the term "some" as used herein may be understood as "none" or "one" or "more than one" or "all." Therefore, the terms "none," "one," "more than one," "more than one, but not all" or "all" would fall under the definition of"some." It should be appreciated by a person skilled in the art that the terminology and structure employed herein is for describing, teaching, and illuminating some embodiments and their specific features and elements and therefore, should not be construed to limit, restrict or reduce the spirit and scope of the present disclosure in any way.For example, any terms used herein such as, "includes," "comprises," "has," "consists," and similar grammatical variants do not specify an exact limitation or restriction, and certainly do not exclude the possible addition of one or more features or elements, unless otherwise stated. Further, such terms must not be taken to exclude the possible removal of one or more of the listed features and elements, unless otherwise stated, for example, by using the limiting language including, but not limited to, "must comprise" or "needs to include."Whether or not a certain feature or element was limited to being used only once, it may still be referred to as "one or more features" or "one or more elements" or "at least one feature" or "at least one element." Furthermore, the use of the terms "one or more" or "at least one" feature or element do not preclude there being none of that feature or element, unless otherwise specified by limiting language including, but not limited to, "there needs to be one or more..." or "one or more elements is required."Unless otherwise defined, all terms and especially any technical and / or scientific terms, used herein may be taken to have the same meaning as commonly understood by a person ordinarily skilled in the art.Reference is made herein to some "embodiments." It should be understood that an embodiment is an example of a possible implementation of any features and / or elements of the present disclosure. Some embodiments have been described for the purpose of explaining one or more of the potential ways inwhich the specific features and / or elements of the proposed disclosure fulfil the requirements of uniqueness, utility, and non-obviousness.Use of the phrases and / or terms including, but not limited to, "a first embodiment," "a further embodiment," "an alternate embodiment," "one embodiment," "an embodiment," "multiple embodiments," "some embodiments," "other embodiments," "further embodiment", "furthermore embodiment", "additional embodiment" or other variants thereof do not necessarily refer to the same embodiments. Unless otherwise specified, one or more particular features and / or elements described in connection with one or more embodiments may be found in one embodiment, or may be found in more than one embodiment, or may be found in all embodiments, or may be found in no embodiments. Although one or more features and / or elements may be described herein in the context of only a single embodiment, or in the context of more than one embodiment, or in the context of all embodiments, the features and / or elements may instead be provided separately or in any appropriate combination or not at all. Conversely, any features and / or elements described in the context of separate embodiments may alternatively be realized as existing together in the context of a single embodiment.Any particular and all details set forth herein are used in the context of some embodiments and therefore should not necessarily be taken as limiting factors to the proposed disclosure. Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.For the sake of clarity, the first digit of a reference numeral of each component of the present disclosure is indicative of the Figure number, in which the corresponding component is shown. For example, reference numerals starting with digit "1" are shown at least in Figure 1. Similarly, reference numerals starting with digit "2" are shown at least in Figure 2.Figures 1 to 4 illustrates different views of an apparatus 100 for evaluating the permeation of toxic chemical through a specimen 102. Specifically, Figure 1 illustrates an exploded view of an apparatus to measure permeation of a toxic chemical through a specimen in L / L configurations for static-diffusion flow mode. Further, Figure 2 illustrates an exploded view of the apparatus 100 having a first polytetrafluoroethylene (PTFE) layer, according to an embodiment of the present disclosure and Figure 3 illustrates an exploded view of the apparatus 100 having a second polytetrafluoroethylene (PTFE) layer. Further, Figure 4 illustrates an exploded view of the apparatus 100 having a ring of colorimetric paper, according to an embodiment of the present disclosure.The apparatus 100 may be employed to evaluate the permeation of toxic chemical through a specimen 102. The specimen 102, also called as a swatch 102 is a piece of fabric of a chemhazard suit. The specimen 102 is tested to determine how good the chemhazard suit is capable of protecting the wearer from the toxic chemical. The apparatus 100 is capable of testing specimen 102 against toxic chemicals, such as nerve agents like (GB, GD, GA, VX, and Novichoks). Further, the apparatus 100 may enable a tester to perform the quantitative analysis in L / L configuration in which the toxic chemical is tested in liquid form. In other words, the apparatus 100 allows a tester to determine degree of permeation of toxic chemicals in liquid form which was not previously possible in L / L configuration.The apparatus 100 may include, but is not limited to, a first cell body 104, a second cell body 106, a first cap 108 with a septa 108A, a second cap 110 with a septa 110A, an O ring 112, a pair of C-clamp 114, 116, a first PTFE layer 118, a second PTFE layer 120, and a ring of colorimetric detector paper 122, details of which will be provided in subsequent embodiments.Referring now to Figures 1 to 4, the first cell body 104 and the second cell body 106 may form a major portion of the apparatus 100. The first cell body 104 may include a cavity through which toxic material is spiked on the specimen 102.Similarly, the second cell body 106 may also include a cavity to hold the sorbent therein. Further, the first cell body 104 and the second cell body 106 may together form an airtight chamber that may prevent vaporization of the toxic material during the testing. Moreover, the airtight chamber may also prevent any leakage of the toxic material and prevent disaster during unwanted leakage of the toxic material. Such an arrangement may also prevent any unwanted contamination of the sorbent or the specimen 102. The airtight chamber may house the specimen 102 right in the center of the airtight chamber, such that a first side of the specimen 102 may receive the toxic material while a second side, opposite to the first side of the specimen 102 may receive the sorbent.The first cap 108 may provide access to the cavity inside the first cell body 104 while the second cap 110 may provide access to the cavity inside the second cell body 106. In one example, the toxic material may be spiked through the cavity of the first cell body 104 by removing the first cap 108. Similarly, the sorbent may be filled in the cavity of the second cell body 106 by removing the second cap 110. Although not shown, the first cap 108 and the second cap 110 may include sealant to provide airtight sealing at the ends of the first cell body 104 and the second cell body 106 respectively. While the first cap 108 and the second cap 110 may provide sealing from the ends of their respective cell bodies, the O rings 112 may provide sealing at the proximal ends of the first cell body 104 and the second cell body 106. The O rings 112 may be made of a material that is both gas and liquid impervious and may be chemically inert against the sorbent or the toxic material. The O rings 112 may be positioned proximate to the first side and the second side of the specimen 102.In one example, the first cell body 104 and the second cell body 106 may be secured to each other using the pair of clamps 114, 116. The clamp 114 may be termed as a first clamp 114 while the clamp 116 may be termed as a second clamp 116. The first clamp 114 and the second clamp 116 may be positioned to secure a first flange 104A of the first cell body 104 and a second flange 106A of thesecond cell body 106 to each other. The first clamp 114 and the second clamp 116 may be C-clamp having arms. In one example, the first clamp 114 may include arms 114A, 114B and each arm 114A, 114B may include a hole 114C there through. Similarly, the second clamp 116 may include arms 116A, 116B and each arm 116A, 116B may include holes 116C there through. During assembly, the holes 114C and 116C may receive fasteners 124, such as screws to push the arms 114A, 114B, 116A, 116B against the first flange 104A and the second flange 106A. Further, the screws may be tightened to firmly secure the first flange 104A and the second flange 106A.During assembly, the specimen 102 may be placed between the first cell body 104 and the second cell body 106, and the first cell body 104 and the second cell body 106 to be coupled together using the clamps 114, 116 to seal off the specimen 102.Although Figure 1 shows a primary structure of the apparatus 100, different embodiments of the apparatus 100 may be envisioned to further enhance the permeation test. Referring now to Figure 2, the apparatus 100 may include the first PTFE layer 118 that may abut to the first side of the specimen 102. The first PTFE layer 118 may be proximate to the first side of the specimen 102. Similarly, the apparatus 100 may include a second PTFE layer 120 proximate to the second side of the specimen 102 as shown in Figure 3. The first PTFE layer 118 may be configured to contain the toxic chemical and prevent the channelling through the specimen 102 via its first side. There is a possibility exist that instead of passing all the toxic material through specimen 102, it travels through the edges of the specimen 102 and reach to the lower compartment despite of O rings 112 preventing the passage of contamination to the edges of the specimen 102. This leakage defeats the test method and permeation test completely. Such an instalment of the second PTFE layer 120 validates the permeation test by preventing major instances of contamination of sorbent material by the toxic material.In one example, some of the toxic material may seep through edges of the specimen 102 thereby contaminating the sorbent by a greater volume than the volume of the toxic material that would permeate through the specimen 102. Detection of leakage is more difficult in case the toxic material is a colourless liquid. Such instances may be detected by providing the ring of colorimetric detector paper 122 at the second side of the specimen 102. The ring of colorimetric detector paper 122 is placed in between swatch sample and test cell lower body near to edges as shown in Figure 4, such that the leaked toxic material from the edges of the specimen 102 may contact the edges of the ring of colorimetric detector paper 122. The ring of colorimetric detector paper 122 is configured to change colour in response to coming in contact with the toxic material. If contamination is passed through edges instead of passing through exposed area of swatch sample, colorimetric paper changes its colour.According to the present disclosure, the sorbent contaminated by the toxic material permeated through the specimen 102 may be evaluated to determine the volume of toxic material that has permeated through the specimen 102. In one example, the sorbent may be retrieved from the second cell body 106 and quantitative analysis may be performed thereon. In one example, the quantitative analysis is performed by chromatography technique.The present disclosure also relates to a method 500 for measuring permeation of a toxic chemical through the specimen 102. The order in which the method 500 steps are described below is not intended to be construed as a limitation, and any number of the described method 500 steps can be combined in any appropriate order to execute the method 500 or an alternative method 500. Additionally, individual steps may be deleted from the method 500 without departing from the spirit and scope of the subject matter described herein.In one example, the method 500 can be performed partially or completely using the apparatus 100. The method may begin at step 502 at which the specimen 102 may be placed in the airtight chamber of the apparatus 100. In one example, the specimen 102 may be placed in between the cavities of the first cell body 104 and the second cell body 106. Thereafter, the O rings112 may be placed on either sides of the specimen 102 and the first cell body 104 and the second cell body 106 may be sealed together using the clamps 114, 116. Thereafter, at step 504, a predetermined volume of the sorbent may be supplied to the cavity proximate to the second side of the specimen 102. In one example, the sorbent may be filled through the second cap 110 into the second cell body 106, such that the sorbent touches the second side of the specimen 102.At step 506, a predetermined volume of the toxic material may be supplied to the first side of the specimen 102. In one example, the toxic material may be supplied. Further, as a part of supplying the toxic material, the predetermined volume of toxic material on the specimen may be spiked on the first side of the specimen 102. Further, at step 508, the arrangement may be held for a predetermined period of time and at preset temperature. While holding the arrangement, the permeation may occur by static-diffusion mode. Further, the apparatus100 is placed in the incubator at a preset temperature to control the environmental conditions. As the permeation proceeds, sorbent material gets exposed to the toxic material. Finally, at step 510, the sorbent from the second cell body 106 may be removed and quantitative analysis may be performed. In one example, quantitative analysis may be performed to determine a degree of contamination the sorbent by the toxic material to determine a volume of toxic material in the sorbent upon the lapse of predetermined period of time. Further, the volume of the toxic material in the sorbent is indicative of the degree of permeation of the toxic chemical on the specimen 102.In an embodiment, the aforementioned method 500 is carried for different types of toxic materials. To maintain the same contamination density acrossdifferent toxic materials, 1 drop (1 μL in case of nerve agent and 0.8μL in case of HD) is spiked onto the exposed area 102A of 1 cm2o f specimen 102. Also, contamination density may be varied as per the requirement of permeation test conditions for each type of toxic material.In one example, the specimen 102 of minimum 1.5cm diameter with exposed surface areas of 1.0 cm2 is used. Further, the first side of specimen 102 is challenged with the single drop of 1.0 mg of toxic material at contamination area 5 through the first cap 108 to maintain the desired contamination density of 10 g / m2. Further, quantitative determination of permeation is measured by desorption of toxic material from sorbent material using a solvent and analyses using chromatography technique. The test conditions of quantitative permeation test in L / L configuration are mentioned in Table 1 shown in Figure 6.As for the specimen 102, two materials, activated carbon sphere (ACS) based three layered composite and activated carbon fabric (ACF) based three layered composite as per Table 2 shown in Figure 7 were evaluated against one compound of interest VX. The permeation test was carried for six hours. More than 10 replicates were tested for each composite, as well as minimum 5 control samples were tested. The test method was based on the above-described modified quantitative test mode in L / L configuration. For the permeation test, the apparatus 100 post the arrangement was placed in an incubator. The test results of the permeation test conducted using the apparatus of Figure 1 by implementing the method of Figure 5 are illustrated in Table 3 shown in Figure 8.Various quality controls are incorporated into the testing protocols of permeation testing including purity analyses of contamination, efficiency of sorbent material, positive control samples, negative control samples, verification of contamination quantity, testing leakage through edges of test sample and analytical control. The quality controls are further described hereinFor the specimen 102, the specimen 102 are cut with sharp edged steel die and press. For the protective chemhazard body suit, an equal number of swatches are taken from front, back, arms and legs. Gas tight syringe may be used for spiking the liquid toxic material onto the sample swatch. A calibrated balance may be used for the verification of the weight of spiked toxic material. Solvents used in the testing are of chromatography grade.As a part of quality control of the apparatus 100, the efficiency of sorbent material is determined. For determining efficiency of sorbent with respect to particular toxic material, solution of 5 μg, 10 μg, 100 μg, 500μg and 5 mg of the chemical in solvent is spiked onto the 500 mg sorbent material separately. This wets the larger area of the sorbent material. The total mass adsorbed fits within the calibration curve of analytical instrument and is within the range of concentrations in which the sorbent material is expected to perform. Once the solvent is evaporated, sorbent material is taken and extracted with 20 mL of ethyl acetate for approximate 30 minutes and quantitative determination is carried out by fitting the data into calibration curve based on the standard solutions of the chemical. Other solvents may be used, as appropriate for the particular toxic materials and / or analytical technique. The extractant is analysed with gas chromatography-mass spectrometer (GC-MS) (not shown) having quantification limit of approximately 1 μg / mL. Improved limit of detection may be achieved using other analytical tools.As for the toxic material, the toxic material of high purity was used because use of low purity toxic material may lead to incorrect results. The purity of the toxic material may be checked using analytical tool such as Nuclear Magnetic Resonance (NMR) Spectroscope (not shown).The repeatability of gas tight syringe may be checked using gravimetric method. The target amount taken into gas tight syringe may be weighed accuratelyby taking into a vial using calibrated electronic balance (not shown) and variance may be recorded.The temperature of the incubator (not shown) may be set to approximate at 32°C or any other desired value and verified using a calibrated temperature recorder (not shown). The apparatus 100 may be allowed to equilibrate for at least 24 hours prior to each test. Temperature may be recorded every minute to note the variance. Other temperature may be used as required by test conditions.According to the present disclosure, a positive control sample is required before or simultaneously with testing the actual sample. The purpose of positive control sample is to ensure the performance of testing methodology and apparatus used. Butyl rubber / material with known permeation density in case of HD and neoprene / material with known permeation density for nerve agents (GB, GD, GA, VX and novichokes) in the controlled conditions may be taken as positive control sample.A negative control sample is also required to run before or simultaneously with the actual sample. Negative control sample could be the same as positive control sample but without any contamination. The purpose of negative control is to demonstrate the proper working of test apparatus and methodology and there is no cross contamination that could occur from tools or other test cells. Toxic materials are not measured above the quantification limit for any of the negative control samples.Further, the analytical methods may include a preparation of calibration curve using quality check samples to increase the confidence in the data. The limit of quantitation is measured by the standard sample of lowest concentration in the calibration curve. The calibration curve should be linear with value of R2 ranging from 0.995 to 0.999.Further, to assess the upper limit for bias and account for sample loss due to interaction of toxic material with the PTFE layers, second PTFE layer 120 is spiked with the contamination and placed over test cell lower body. Toxic materials were covered with first PTFE layer 118. After a certain duration, the sample follows the same test process but without sorbent material. Both the PTFE layers 118, 120 are extracted independently and sample loss was checked by comparing the extracted quantity of toxic material to the original toxic material amount. The sum of PTFE layers extraction results is expected to equal the original contamination level. The difference is attributed to potential loss during the entire process.The apparatus 100 and method 500 of the present disclosure enables the quantitative analysis of specimen 102 in L / L configuration previously not possible. Moreover, embodiments of the apparatus 100 may be amenable to air impermeable, semi permeable and air permeable specimen 102.While specific language has been used to describe the present disclosure, any limitations arising on account thereto, are not intended. As would be apparent to a person in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. The drawings and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment.
Claims
1. An apparatus (100) for measuring permeation of toxic chemicals on a specimen (102), the apparatus (100) comprising: a first cell body (104) and a second cell body (106) defining an airtight chamber there between, the chamber is adapted to receive the specimen (102); a first cap (108) attached to the first cell body (104) and adapted to supply a predetermined volume of the toxic chemical to the chamber on a first side of the specimen (102); a second cap (110) attached to the second cell body (106) and adapted to supply a sorbent to the chamber on a second side of the specimen (102), wherein a degree of permeation is determined by quantitative analysis and the degree of permeation is measured as a degree of contamination in sorbent of the toxic material.
2. The apparatus (100) as claimed in claim 1 wherein the quantitative analysis is performed using chromatography technique.
3. The apparatus (100) as claimed in claim 1 comprising: an O ring (112) around the chamber to chamber to prevent leakage of the toxic material from the chamber, wherein the toxic material is prevented from vaporizing; a pair of C-clamp (114, 116) on either side of the O ring (112) to secure the first cell body (104) and the second cell body (106) together; a first PTFE layer (118) proximate to the first side of the specimen (102), wherein the first PTFE layer (118) to contain the toxic chemical and prevent the channelling through the specimen (102) via the first side; a second PTFE layer (120) on the second side of the specimen (102), prevent the contamination of sorbent around the specimen (102) via the second side to validate the degree of contamination; and a ring of colorimetric detector paper (122) around edges of the specimen (102) on the second side of the specimen (102), wherein the colorimetric detector paper (122) is adapted to change of colour upon contacting the toxic material.
4. The apparatus (100) as claimed 1, wherein the specimen (102) is one of an air impermeable material, air permeable material, and semi-permeable material.
5. A method of measuring permeation of a toxic chemical through a specimen (102), the method comprising: placing a specimen (102) in an airtight chamber of an apparatus (100); placing a predetermined volume of sorbent to a second side of the specimen (102); spiking a predetermined volume of toxic material to a first side of the specimen (102); holding the arrangement of the toxic material and the sorbent with respect to the specimen (102) for a predetermined period of time; and performing quantitative analysis to determine a degree of contamination the sorbent by the toxic material to determine a volume of toxic material in the sorbent upon the lapse of predetermined period of time, wherein the volume of the toxic material in the sorbent is indicative of the degree of permeation of the toxic chemical on the specimen (102).
6. The method as claimed in claim 1 wherein the quantitative analysis is performed by chromatography technique.
7. The method as claimed in claim 1 supplying the predetermined volume of toxic material comprising spiking the toxic material on the specimen (102) and wherein the toxic material is prevented from vaporising during the holding of the arrangement.
8. The method as claimed in claim 1 comprising: placing a first polytetrafluoroethylene (PTFE) layer on the first side of the specimen (102), wherein the first PTFE layer (118) contains the toxic chemical around the specimen (102) via the first side;9. The method as claimed in claim 1 comprising: placing a second PTFE layer (120) on the second side of the specimen (102), wherein permeation, wherein the second PTFE layer (120) prevent the contamination of sorbent around the specimen (102) on the second side of specimen; and validating the method of permeation through the specimen (102)10. The method as claimed in claim 1 comprising: placing a ring of colorimetric detector paper (122) around edges of the specimen (102) on the second side of the specimen (102), wherein the colorimetric detector paper (122) is adapted to change of colour upon contacting the toxic material; and determining a leakage via the edges of specimen (102) instead through of specimen (102) upon the change of colour of the colorimetric detector paper (122). placing an O ring (112) around the chamber to prevent leakage of the toxic chemical through the chamber.