Sensitive semi-quantitative trinitrotoluene test paper and preparation and use methods thereof

Abstract

The invention discloses sensitive semi-quantitative TNT (trinitrotoluene) detection test paper as well as a preparation method and a use method thereof, the use method of the test paper is similar to that of new crown test paper, and whether a detection object (solid, liquid and gas) contains trace TNT or not can be quickly judged on site. The invention designs a whole-process TNT detection method, provides a preparation, production and standardized colorimetric quantitative method of the TNT test paper, provides a product package development scheme for rapidly detecting TNT on site, and the method is sensitive, semi-quantitative, rapid in response (color identification is distinguished in 5-10 seconds), low in cost (the controllable cost is 0.5-1 yuan per piece at present), high in sensitivity, high in sensitivity and high in sensitivity, and can be used for rapidly detecting the TNT. And rapid semi-quantitative detection of TNT in an actual detection scene can be better met.

Description

Technical Field

[0001] The invention relates to the field of trace explosive analysis, in particular to a sensitive semi-quantitative trinitrotoluene (TNT) detection test paper and a use and production method thereof. Background Art

[0002] Explosives are the most common form of terrorist crimes to date, due to their ease of preparation and production, and their ability to cause tens of thousands of casualties and huge property losses. Therefore, the detection of explosives has become one of the most pressing issues in international security. The recent rise of international terrorist activities has also stimulated the development of wireless / remote, high-sensitivity and low-cost explosive detection technologies. In addition, due to the widespread use of explosives, the detection and analysis of explosives is crucial for judicial evidence research, mine detection, and identification of explosive residues in environmental issues. In terms of military use, the large-scale use of 2,4,6-trinitrotoluene (TNT) has also attracted widespread attention to environmental pollutants caused by its production and storage. Short-term or long-term exposure to TNT poses a huge public health threat to animals and humans, such as anemia, carcinogenesis, abnormal liver function, cataract formation and skin irritation.

[0003] As one of the most widely used explosives, TNT's adverse effects on national defense security, ecological environment and human health have attracted widespread attention, which has prompted researchers to develop economical, efficient, selective, portable, rapid and sensitive detection methods for rapid detection of TNT. At present, the complex colorimetric method is a method in which TNT and conjugated probe molecules are colored to produce naked eye recognition. There are a lot of research papers based on this method, but the TNT test paper developed by this method, especially the TNT test paper standard for large-scale commercial use, is still vacant. The test paper developed by this patent has been widely tried in the field of explosives and fire, and its stability, sensitivity and ease of use have certain advantages and practical verification. Summary of the invention

[0004] The purpose of the present invention is to provide a sensitive semi-quantitative trinitrotoluene (TNT) detection test paper and a method for preparing and using the same in order to solve the above problems. The method can perform semi-quantitative detection of TNT in a sample through a colorimetric card.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0006] The invention provides a sensitive semi-quantitative trinitrotoluene (TNT) detection test paper, comprising a test area (T area), a control area (C area), a PVC bottom plate, and absorbent paper. The bottom layer of the test paper is the PVC bottom plate, followed by the absorbent paper, and the T area and the C area are respectively attached by glue.

[0007] The present invention also provides a method for preparing a sensitive semi-quantitative trinitrotoluene (TNT) detection test paper, comprising the following steps:

[0008] Step S11, select a probe molecule that can produce a π-π conjugated chromophore with TNT, such as p-mercaptoaniline, long-chain mercaptoalkylamine, 3-aminopropyltriethoxysilane, etc. Use low-cost filter paper as the probe loading substrate, load it on absorbent paper, load the absorbent paper onto a PVC bottom plate, and cut it into test strips with a width of 1-3 cm.

[0009] Step S12, establish a quality control area and a detection area on the test strip. The detection test strip on the quality control area can be a commercial pH test strip, or other commercial stable test strips that can represent qualified products, such as phenolphthalein test strips for alkalinity detection, potassium iodide starch test strips, etc. The main function is to evaluate whether the test strip can be used normally.

[0010] Step S13, stick the filter paper loaded with probes on the detection area, and obtain standard display test paper by dripping TNT standard solutions of different concentrations. Use the program numerical algorithm to extract the chromaticity of the colorimetric test paper standard and establish a colorimetric numerical model. And use the colorimetric numerical model in the form of comparison with the standard color value card. The detection area is used for the detection of actual samples. The color change results are compared with the standard color card to preliminarily determine the concentration of TNT in the object to be tested. When the filter paper is loaded with probes, the concentration does not exceed saturation. After loading the probe solution, it dries naturally without curling or cracking to be qualified. The added TNT standard solution is 5×10 -5 mol / L,1×10 -4 mol / L,1×10 -3 mol / L,1×10 -2 mol / L, 0.1mol / L. After obtaining the standard color test paper, extract the color chromaticity of no less than 100 pixels, and obtain the color value data of the standard color comparison card from the inside of the standard color test paper, without extracting the edge or uneven color value.

[0011] The test paper is the core part of the product. In addition, the TNT detection product also includes the following materials: a reaction pad T treated with a TNT complexing agent, a reaction pad C treated with a pH indicator, a bottom plate, absorbent paper, a sample treatment solution A, a sample extraction dropper, a dropper, and a sampling cotton swab, among which:

[0012] name Specification Loading Treated reaction pad T 1cm×0.8cm 1 piece Treated reaction pad C 1cm×0.8cm 1 piece Base Plate 7.8cm×0.8cm 1 piece Absorbent paper 2.8cm×0.8cm 1 piece Sample extraction pipette 3mL 2 Dropper 3mL 2 Sampling swab 10cm / 15cm 10 sticks Ethanol / 1mL

[0013] Storage conditions and validity period requirements:

[0014] The test strips should be stored in a sealed container to avoid moisture and exposure to direct sunlight. It is best to store the test strips in a dry, cool place to avoid temperatures that are too high or too low, 2 to 30°C is the most suitable, and the validity period is 10 months.

[0015] After opening the aluminum foil bag, it should be used within 1 hour. If the sample processing liquid is used, it should be covered immediately and used within the validity period.

[0016] Production date, expiration date: see the product packaging.

[0017] Test sample requirements: After the specimen is collected, it should be processed with the sample processing solution provided by this product as soon as possible. If it cannot be processed immediately, the sample should be immediately stored in a dry, light-proof, and strictly sealed container.

[0018] Inspection method:

[0019] Before conducting any test, you must read the instruction manual in full. Before use, take out the reagents and samples from storage conditions, equilibrate to room temperature (18-25°C), and number them.

[0020] The test process can be referred to the figure below. The present invention also provides a method for using a sensitive semi-quantitative trinitrotoluene (TNT) test paper, comprising the following steps:

[0021] Step S21, use the cotton swab in the product to dip a small amount of sample for sampling. The cotton swab of appropriate size can be selected according to the actual situation to ensure that the sample is not contaminated by other substances during the collection process.

[0022] Step S22, insert the sampled cotton swab into the ethanol in the dropper, and rotate it close to the inner wall of the test tube for about 10 times to dissolve the specimen in the ethanol as much as possible.

[0023] Step S23, squeezing the cotton swab head of the swab along the inner wall of the dropper tube to keep the liquid in the tube as much as possible, and taking out and discarding the cotton swab.

[0024] Step S24, cover the dripper.

[0025] Step S25, take the test paper out of the aluminum foil bag and place it on a clean and flat table, place it horizontally and mark it, avoid direct contact with fingers to avoid interference with the test paper.

[0026] Step S26, vertically drip 1-2 drops of the treated sample solution onto the test strips in the detection areas T and C (positions as shown in the figure below).

[0027] Step S27, after a specific color change occurs, the color of the test paper is compared with the colorimetric card in the package to determine the presence or concentration of TNT in the sample and interpret the result.

[0028] The beneficial effects of the present invention are: a full-process TNT detection method is designed, a preparation, production and standardized colorimetric quantitative method of TNT test paper is provided, and a product package development plan for on-site rapid detection of TNT is provided. The method is sensitive, semi-quantitative, and has a fast response (5-10s to distinguish color identification) and low cost (the current controllable cost is 0.5-1 yuan per stick), which can better meet the rapid semi-quantitative detection of TNT in actual detection scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a flow chart of the on-site rapid detection of TNT of the present invention;

[0030] Figure 2 This is a schematic diagram of the material composition of the TNT test paper product of the present invention;

[0031] Figure 3 The design diagram and production diagram of the TNT test paper of the present invention;

[0032] Figure 4 The standard color chart of TNT extraction color value with different concentrations (5×10-5mol / L, 1×10-4mol / L, 1×10-3mol / L, 1×10-2mol / L, 0.1mol / L) of the present invention;

[0033] Figure 5 This is a graph showing the test and comparison results of actual samples of explosion-proof doors contaminated with trace amounts of TNT according to the present invention. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention clearer, the implementation method of the present invention will be described in detail below in conjunction with the accompanying drawings and embodiments, so that the implementation process of how the present invention applies technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0036] Example 1

[0037] This test paper uses the Meisenheimer complexation principle to semi-quantitatively detect the presence and content of explosive TNT in the sample. Figure 1 As shown in the figure, the sample to be tested is mixed with the detection treatment solution and then dripped into the detection area (T area). The color reagent in the T area (position as shown in the figure below) will react with the target TNT within 2 minutes. If the sample to be tested contains TNT and the concentration is higher than 1×10 -5mol / L, the T zone test paper turns from white to yellow, and the depth of yellow is proportional to the TNT concentration. After comparison and interpretation with the colorimetric card, the TNT concentration can be semi-quantitatively determined. Since this product is only suitable for samples with a pH of 5.0-8.0, the quality control area (area C) is set as a pH indicator test paper. The test solution is added to the C zone, and compared with the colorimetric card to further determine whether the extracted amount meets the standard of sufficient sample and pH detection.

[0038] Example 2

[0039] A quality control area and a detection area are established on the test strip. The test strips on the quality control area can be commercial pH test strips, or other commercial stable test strips that can represent qualified products, such as phenolphthalein test strips for alkalinity testing, potassium iodide starch test strips, etc. The main function is to evaluate whether the test strips can be used normally ( Figure 2 , Figure 3 ). In order to facilitate operation and product production, this embodiment shows the material consumables package required for the TNT test paper product, specifically including, treated reaction pad T (1cm×0.8cm, one sheet); treated reaction pad C (1cm×0.8cm, one sheet); bottom plate (7.8cm×0.8cm, one sheet); absorbent paper (2.8cm×0.8cm, one sheet); sample extraction dropper (3mL); dropper; sampling cotton swab (10cm / 15cm); ethanol (0.5mL). For solid samples, they can be directly placed in a dropper filled with ethanol for extraction and then added to the quality control area and detection area of ​​the test paper. For colorless liquid samples, they can be directly added to the quality control area and detection area of ​​the test paper. For dark liquid samples, they can be dropped into a dropper filled with ethanol for dilution and then added to the quality control area and detection area of ​​the test paper.

[0040] Example 3

[0041] The standard TNT solution was used with different concentrations (5×10 -5 mol / L,1×10 -4 mol / L,1×10 -3 mol / L,1×10 - 2 mol / L, 0.1mol / L) components are dropped onto the test paper for testing, and the test paper changes color. After taking pictures with a digital camera, the color value is extracted and a standard color card for TNT extraction color value is established (such as Figure 4 ).

[0042] Example 4

[0043] For sampling and testing on explosion-proof doors with trace amounts of TNT attached, use the cotton swab in the product to dip a small amount of the sample for sampling. You can choose a cotton swab of appropriate size according to the actual situation to ensure that the sample is not contaminated by other substances during collection. Insert the sampled cotton swab into the ethanol in the dropper tube, and rotate it close to the inner wall of the test tube for about 10 times to dissolve the specimen in the ethanol as much as possible. Squeeze the cotton swab head of the swab along the inner wall of the dropper tube to keep the liquid in the tube as much as possible, remove and discard the cotton swab. Cover the dropper. Take the test paper out of the aluminum foil bag and place it on a clean and flat table. Place it horizontally and mark it to avoid direct contact with your fingers to avoid interference with the test paper. Vertically add 1-2 drops of the treated sample solution to the test paper in the detection T and C zones of the test strip (position 3). After a specific color change occurs, compare the color of the test paper with the colorimetric card in the package to determine the presence or concentration of TNT in the sample and interpret the results ( Figure 5 ).

[0044] Although the present invention is described herein with reference to the illustrative embodiments of the present invention, the above embodiments are only preferred embodiments of the present invention, and the embodiments of the present invention are not limited to the above embodiments. It should be understood that those skilled in the art can design many other modifications and embodiments, which will fall within the scope and spirit of the principles disclosed in this application.

Claims

1. A sensitive semi-quantitative trinitrotoluene test paper, comprising a test area (T area), a control area (C area), a PVC base plate, and absorbent paper. The bottom layer of the test paper is the PVC base plate, followed by the absorbent paper, and the T area and the C area are respectively attached with glue.

2. A method for preparing a sensitive semi-quantitative trinitrotoluene test paper as claimed in claim 1, comprising the following steps: Step S11, selecting a probe molecule that can produce a π-π conjugated chromophore with TNT, using low-cost filter paper as the probe loading substrate, loading it on absorbent paper, loading the absorbent paper onto a PVC bottom plate, and cutting it into test strips with a width of 1-3 cm; Step S12, establishing a quality control area and a detection area on the test strip; Step S13, stick the filter paper loaded with the probe on the detection area, obtain the standard display test paper by dropping TNT standard solution of different concentrations, extract the chromaticity of the colorimetric test paper standard by using the program numerical algorithm, establish the colorimetric numerical model, and use the colorimetric numerical model in the form of comparison with the standard color value card.

3. A method for preparing a sensitive semi-quantitative trinitrotoluene test paper according to claim 2, characterized in that: The test paper on the quality control area can be a commercial pH test paper or a commercial stability test paper.

4. A method for using the sensitive semi-quantitative trinitrotoluene test paper as claimed in claim 1, comprising the following steps: Step S21, use the cotton swab in the product to dip a small amount of sample for sampling. The cotton swab of appropriate size can be selected according to the actual situation to ensure that the sample is not contaminated by other substances during the collection process; Step S22, inserting the sampled cotton swab into the ethanol in the dropper, and rotating it close to the inner wall of the test tube for about 10 times to dissolve the sample in the ethanol as much as possible; Step S23, squeezing the cotton swab head of the swab along the inner wall of the dropper tube to keep the liquid in the tube as much as possible, and taking out and discarding the cotton swab; Step S24, cover the dripper; Step S25, take the test paper out of the aluminum foil bag and place it on a clean and flat table, place it horizontally and mark it, avoid direct contact with fingers to avoid interference with the test paper; Step S26, vertically dripping 1-2 drops of the treated sample solution onto the test strips in the detection areas T and C; Step S27, after a specific color change occurs, the color of the test paper is compared with the colorimetric card in the package to determine the presence or concentration of TNT in the sample and interpret the result.

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