A method for repeatedly detecting 2,4,6-trinitrotoluene using a wiping fluorescent test paper

Abstract

The present invention provides a method for repeatedly detecting 2,4,6-trinitrotoluene by wiping fluorescent test paper, and the method is to perform fluorescence detection based on test paper modified with glutathione copper nanoclusters (GSH-CuNC). After quenching of 2,4,6-trinitrotoluene (TNT) by wiping detection, the prepared fluorescent test paper can be soaked in acetonitrile for 1-5s to restore strong orange fluorescence, and the test paper with restored fluorescence can continue to wipe the TNT powder residue on the solid surface to achieve rapid detection of repeatable fluorescence quenching. The fluorescent test paper can be recycled many times in this way, and the number of tested cycles is at least 10 times. The method provided by the present invention has the characteristics of simple operation, low price, high degree of visualization, etc., which is conducive to the detection of hidden TNT in complex on-site environments. Provide effective technical means for the detection of explosion cases by the criminal investigation department of the public security system.

Description

Technical Field

[0001] The invention belongs to the field of environment and standard explosive raw material detection, and provides a method for repeatedly detecting 2,4,6-trinitrotoluene by using a wiping type fluorescent test paper which is not only stable in storage but also green and non-toxic. Background Art

[0002] In recent years, conducting research on explosive detection and analysis is a prerequisite and necessary means to effectively curb explosion attacks. Nitro explosives are extremely powerful. 2,4,6-trinitrotoluene (TNT), known as the king of explosions, is still widely used due to its strong explosive power and stable properties. At the same time, 2,4,6-trinitrotoluene (TNT) will pollute the environment, have serious toxic effects on plants, and cause irreversible harm to the human body. Therefore, the detection of 2,4,6-trinitrotoluene (TNT) is of great significance to the safety of people's lives and property. (Journal of Materials Chemistry C, 2018, 6 (45): 12142-58)

[0003] At present, commonly used 2,4,6-trinitrotoluene (TNT) detection technologies include: metal detectors (Education and Urban Society, 2010, 43 (4): 486-98), surface enhanced resonance Raman spectroscopy (CN103091300A), ion mobility spectrometry (Analytical Chemistry, 1990, 62 (23): 1201A-9A), etc. However, these testing methods require precise and expensive instruments and systematically trained testing personnel, and cannot meet the requirements of rapid, sensitive, and convenient testing required in on-site testing technology. Therefore, the existing methods are not suitable for use in complex and real on-site testing, and it is necessary to actively explore rapid, efficient, and inexpensive TNT detection methods.

[0004] Among various detection methods, optical methods have the advantages of high sensitivity and selectivity, low cost, and simple equipment requirements over traditional methods. Therefore, in the field of explosive detection, the research on contrast color or fluorescence response sensors is becoming more and more extensive (Chemical Society Reviews, 2009, 38 (9): 2543-55). However, fluorescence detection is more advantageous than colorimetric detection based on absorbance because it has higher sensitivity and a wider linear range. In addition, it has high specificity, high visualization, and is not affected by environmental humidity and dust. It can be quickly detected using a portable fluorescence device, so it is very promising for on-site detection. Therefore, fluorescence technology has great potential in the rapid, sensitive and selective detection of TNT. (Chemical Society Reviews, 2015, 44 (22): 8019-61)

[0005] Fang Yu's team from Shaanxi Normal University proposed the concept of shielding / enrichment effect of the linker layer and took the lead in developing chemically assembled conjugated polymer membranes to achieve fluorescence quenching detection of the explosive TNT (ACS applied materials & interfaces, 2016, 8 (42): 29128-29135). Cheng Jiangong's team from the Shanghai Institute of Microsystem and Information Technology of the Chinese Academy of Sciences (Synthetic Metals, 2009, 159, 320-324) used a composite material composed of polyphenylene ethylene (PPE) and nano-sized TiO2 particles to detect the explosive TNT through fluorescence quenching caused by charge transfer from polyphenylene ethylene (PPE) to TiO2 particles in the polymer, thus developing the SIM series of explosive detectors. Zhao Jun's team from Harbin Normal University (CN103424388A) used gold nanoclusters modified with bovine serum albumin as colorimetric and fluorescence dual response probes for detecting TNT, which has the characteristics of low detection limit, rapid in situ detection, simple operation and non-toxic reagents.

[0006] However, these fluorescent detection materials usually require cumbersome synthesis steps and subsequent processing processes. The present invention proposes a method for repeatedly detecting 2,4,6-trinitrotoluene by using a wiping fluorescent test paper, which is simple to prepare and does not require complicated post-processing. The fluorescent detection test paper can be directly excited by ultraviolet light to detect TNT, and the test paper can be recycled and reused many times, which meets the requirements of low price and simple operation. Therefore, it is particularly prominent and important to carry out research on the application of copper nanocluster paper-based detection of TNT by fluorescence method. Summary of the invention

[0007] The present invention aims to provide a method for repeatedly detecting 2,4,6-trinitrotoluene by wiping fluorescent test paper, which is based on glutathione-modified copper nanoclusters (GSH-CuNC) test paper for fluorescence detection. After the prepared fluorescent test paper detects TNT quenching, it can be soaked in acetonitrile for 1-5s to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of fluorescence quenching. The fluorescent test paper can be recycled many times in this way, and the number of test cycles is at least 10 times. The method of the present invention has the characteristics of simple operation, low price, high visualization, etc., which is conducive to the detection of hidden 2,4,6-trinitrotoluene (TNT) in complex on-site environments. Provide effective technical means for the detection of explosion cases by the criminal investigation department of the public security system.

[0008] The method of the present invention for repeatedly detecting 2,4,6-trinitrotoluene by a wiping type fluorescent test paper comprises first preparing a fluorescent test paper, and then wiping and detecting 2,4,6-trinitrotoluene solid powder with the fluorescent test paper. The specific operation is performed according to the following steps:

[0009] Preparation of fluorescent test strips:

[0010] a. At room temperature, a 10-100 mM copper nitrate aqueous solution and a 10-100 mM glutathione aqueous solution were stirred and uniformly mixed at a volume ratio of 1:3-1:7 for 1-15 min, and then a 0.5-5 M NaOH aqueous solution was used to adjust the pH to 4.0-9.0 to a light yellow transparent solution, and then anhydrous ethanol was added at a volume multiple of 2.33-49 times the volume of the mixed solution of copper nitrate and glutathione to obtain a copper nanocluster solution;

[0011] b. Soak the cut filter paper in the copper cluster solution obtained in step a for 1-10 hours, and dry it naturally to obtain a deposited fluorescent test paper, which emits bright orange fluorescence under 365nm ultraviolet light;

[0012] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0013] c. Wipe the 2,4,6-trinitrotoluene solid powder remaining on the surface of the suspicious object with the fluorescent test paper prepared in step b, and the fluorescent test paper will be fluorescently quenched. Use a fluorescence spectrometer to scan the fluorescence emission spectrum before and after the fluorescent test paper detection, with the change in fluorescence intensity as the ordinate and the wavelength as the abscissa, to obtain the fluorescence emission spectrum before and after the fluorescent test paper detection for analysis and detection;

[0014] Or use a portable ultraviolet lamp of 330-365nm to directly illuminate the fluorescent test paper to achieve rapid naked eye identification and detection of suspicious scenes to determine the presence of 2,4,6-trinitrotoluene;

[0015] d. After the prepared fluorescence test paper is quenched in TNT, it can be soaked in acetonitrile for 1-5 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the TNT powder residue on the solid surface to achieve rapid detection of repeated fluorescence quenching.

[0016] The present invention discloses a method for repeatedly detecting 2,4,6-trinitrotoluene with a wipe-type fluorescent test paper. The method comprises mixing a copper nitrate aqueous solution and a GSH aqueous solution at a certain molar ratio at room temperature, adjusting the pH with a sodium hydroxide aqueous solution, and finally adding anhydrous ethanol to obtain an orange fluorescent copper nanocluster solution. Figure 1 Fluorescence excitation and emission spectra of copper cluster solution.

[0017] After the cut filter paper strips are soaked in the synthetic copper cluster solution, the filter paper strips are taken out and dried naturally. Orange fluorescence is emitted under a 365nm ultraviolet lamp, indicating that the copper clusters have been successfully deposited on the filter paper surface. The desired fluorescent detection test paper is obtained, such as Figure 2 The fluorescence excitation and emission spectra of the test paper. The prepared fluorescence test paper is wiped with the 2,4,6-trinitrotoluene (TNT) solid powder remaining on the surface of the suspicious object, and the fluorescence of the fluorescence test paper is quenched;

[0018] The invention discloses a method for repeatedly detecting 2,4,6-trinitrotoluene by using a wiping fluorescent test paper. The method mainly detects 2,4,6-trinitrotoluene (TNT) in the environment and standard explosives, and mainly includes solid powdered TNT raw materials, explosives and explosive residues. The size of the test paper can be adjusted by shearing; the trace amount of solid powder residue on the surface of the suspicious object can be wiped with the fluorescent test paper to realize fluorescence quenching detection of 2,4,6-trinitrotoluene (TNT). The fluorescent test paper can be irradiated with a portable ultraviolet lamp (330-365nm) to analyze the quenching detection effect with the naked eye, or the emission spectrum can be scanned with a fluorescence spectrometer with a test paper of 5×15mm. The peak position of the fluorescence intensity change value is 600-630nm. The problem of complex synthesis of fluorescent detection materials, cumbersome operation and inability to conduct rapid on-site detection in the field of fluorescent detection of 2,4,6-trinitrotoluene (TNT) is solved. After the prepared fluorescence test paper is quenched in the detection of 2,4,6-trinitrotoluene (TNT), it can recover strong orange fluorescence by soaking in acetonitrile for 1-5 seconds. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of fluorescence quenching. The fluorescence test paper can be recycled many times in this way, and the number of cycles tested is at least 10 or more.

[0019] The fluorescent test paper obtained by the method of the present invention shows efficient and rapid detection of 2,4,6-trinitrotoluene (TNT), has the characteristics of simple operation, low price, high visualization, etc., which is conducive to the detection of 2,4,6-trinitrotoluene (TNT) components in complex environments and standard explosive raw materials. In addition, the fluorescent test paper reaches naked eye visible fluorescence quenching within 20s after contacting with 2,4,6-trinitrotoluene (TNT) solid powder, without the need for complex analytical equipment, and the test paper can be repeatedly recycled, thereby realizing low-cost, instant detection of 2,4,6-trinitrotoluene (TNT), saving time and effort. Provide effective technical means for the detection of explosion cases.

[0020] Compared with the prior art, the present invention has the following characteristics:

[0021] 1. The reagents and raw materials used in the present invention are cheap, readily available, and environmentally friendly;

[0022] 2. The fluorescent test paper of the present invention has stable luminescence performance, realizes solid phase contact detection, and can be recycled and reused;

[0023] 3. The detection method of the present invention can quickly and efficiently detect solid TNT residues in the environment and standard explosives with naked eyes;

[0024] 4. The detection method of the present invention does not require pre-treatment of the object to be detected, and the detection phenomenon can be observed with the naked eye within 20 seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The fluorescence excitation spectrum (Em618 nm) and fluorescence emission spectrum (Ex330 nm) of the copper nanocluster solution used to prepare the fluorescence detection test paper of the present invention;

[0026] Figure 2 The figure is the fluorescence excitation spectrum (Em618 nm) and fluorescence emission spectrum (Ex330 nm) of the fluorescence detection test paper of the present invention, and the inset is the fluorescence photograph of the fluorescence detection test paper under 365 nm ultraviolet light excitation;

[0027] Figure 3 The figure shows the change of fluorescence intensity before and after the fluorescent test paper of the present invention detects TNT solid powder, as well as the test of the number of cycles of repeated detection. The illustration is the fluorescence photograph under 330nm ultraviolet light excitation corresponding to the 10th cycle detection before and after. The upper figure shows that the center of the test paper can emit orange fluorescence when excited by 330nm before detection, and the lower figure shows that fluorescence quenching occurs after detecting TNT. DETAILED DESCRIPTION

[0028] The present invention is further described by the following specific examples, but the invention is not limited to these specific examples.

[0029] Example 1

[0030] Preparation of fluorescent test strips:

[0031] a. At room temperature, 0.5 mL of 50 mM Cu(NO3)2 aqueous solution and 2.5 mL of 50 mM glutathione aqueous solution were measured and mixed evenly for 5 min, and then the pH was adjusted to 5.0 with 2 M NaOH to a light yellow transparent solution, and then anhydrous ethanol with a volume multiple of 19 times the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0032] b. Soak the cut filter paper in the copper nanocluster solution obtained in step a for 1 hour, and dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 365nm ultraviolet light;

[0033] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0034] c. Wipe the 2,4,6-trinitrotoluene (TNT) solid powder remaining on the surface of the suspicious object with the fluorescent test paper prepared in step b, and the test paper will be fluorescently quenched. Use a fluorescence spectrometer to scan the fluorescence emission spectrum of the test paper before and after detection, and use the change in fluorescence intensity as the ordinate and the wavelength as the abscissa to obtain the fluorescence emission spectrum before and after the paper-based detection for analysis and detection. Figure 3 As shown in the first cycle, it can be seen that after the reaction, the fluorescence emission peak near 618nm is significantly quenched, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0035] d. After the prepared fluorescence test paper is quenched when detecting 2,4,6-trinitrotoluene (TNT), it can be immersed in acetonitrile for 1 second to restore the strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of repeatable fluorescence quenching.

[0036] Example 2

[0037] Preparation of fluorescent test strips:

[0038] a. At room temperature, 0.5 mL of 30 mM Cu(NO3)2 aqueous solution and 2.5 mL of 30 mM glutathione aqueous solution were measured and mixed evenly for 1 min, and then the pH was adjusted to 4.0 with 0.5 M NaOH, and then anhydrous ethanol with a volume multiple of 49 times that of the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0039] b. Soak the cut filter paper in the copper nanocluster solution obtained in step a for 2 hours, and dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 330nm ultraviolet light;

[0040] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0041] c. Wipe the 2,4,6-trinitrotoluene (TNT) solid powder remaining on the surface of the suspicious object with the fluorescent test paper prepared in step b, and irradiate the test paper with a portable ultraviolet lamp at 340nm. The fluorescence is obviously quenched, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0042] d. After the prepared fluorescence test paper is quenched when detecting 2,4,6-trinitrotoluene (TNT), it can be immersed in acetonitrile for 2 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface, realizing rapid detection of repeatable fluorescence quenching.

[0043] Example 3

[0044] Preparation of fluorescent test strips:

[0045] a. At room temperature, 0.5 mL of 50 mM Cu(NO3)2 aqueous solution and 2.5 mL of 50 mM glutathione aqueous solution were measured and mixed evenly for 8 min, and then the pH was adjusted to 6.0 with 1 M NaOH, and then anhydrous ethanol with a volume multiple of 2.33 times the volume of the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0046] b. Soak the cut filter paper in the copper nanocluster solution obtained in step a for 4 hours, and dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 340nm ultraviolet light;

[0047] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0048] c. Wipe the 2,4,6-trinitrotoluene (TNT) solid powder remaining on the surface of the suitcase with the fluorescent test paper prepared in step b, and use a fluorescence spectrometer to scan the fluorescence emission spectrum of the test paper before and after detection, with the change in fluorescence intensity as the ordinate and the wavelength as the abscissa to obtain the fluorescence emission spectrum before and after the paper-based detection. The fluorescence emission intensity near 618nm is significantly reduced, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0049] d. After the prepared fluorescence test paper is quenched when detecting 2,4,6-trinitrotoluene (TNT), it can be soaked in acetonitrile for 1-5 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of repeatable fluorescence quenching.

[0050] Example 4

[0051] Preparation of fluorescent test strips:

[0052] a. At room temperature, 0.5 mL of 50 mM Cu(NO3)2 aqueous solution and 2.0 mL of 50 mM glutathione aqueous solution were measured and mixed evenly for 10 min, and then the pH was adjusted to 7.0 with 3 M NaOH to form a light yellow transparent solution, and then anhydrous ethanol with a volume multiple of 5.66 times the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0053] b. Soak the cut filter paper in the copper cluster solution obtained in step a for 6 hours, and then dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 365nm ultraviolet light;

[0054] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0055] c. Wipe the fluorescent test paper prepared in step b with cotton dipped in 2,4,6-trinitrotoluene (TNT) solid powder, and irradiate the test paper with a portable ultraviolet lamp at 330 nm. After detection, the fluorescence is obviously quenched, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0056] d. After the prepared fluorescence test paper is quenched when detecting 2,4,6-trinitrotoluene (TNT), it can be soaked in acetonitrile for 1-5 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of repeatable fluorescence quenching.

[0057] Example 5

[0058] Preparation of fluorescent test strips:

[0059] At room temperature, measure 0.5mL 50mM Cu(NO3)2 aqueous solution and 2.5mL 50mM glutathione aqueous solution, stir and mix evenly for 15min, adjust the pH to 6.0 with 4M NaOH to a light yellow transparent solution, and then add 4 times the volume of the mixed solution of copper nitrate and glutathione with anhydrous ethanol to obtain a copper nanocluster solution. Soak the cut filter paper in the aforementioned copper cluster solution for 6h, and after natural drying, obtain the deposited fluorescent detection paper, which can emit bright orange fluorescence under 365nm ultraviolet light;

[0060] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0061] The prepared fluorescent test paper is used to wipe the 2,4,6-trinitrotoluene (TNT) solid powder remaining on the suspicious desktop, and the fluorescence emission spectrum before and after the test paper is scanned by a fluorescence spectrometer. The fluorescence intensity change value is used as the vertical coordinate and the wavelength is used as the horizontal coordinate to obtain the fluorescence emission spectrum before and after the paper-based detection. The fluorescence emission intensity near 618nm is significantly reduced, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0062] d. After the prepared fluorescence test paper is quenched when detecting 2,4,6-trinitrotoluene (TNT), it can be soaked in acetonitrile for 1-5 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of repeatable fluorescence quenching.

[0063] Example 6

[0064] Preparation of fluorescent test strips:

[0065] a. At room temperature, 0.5 mL of 50 mM Cu(NO3)2 aqueous solution and 2.5 mL of 50 mM glutathione aqueous solution were measured and mixed evenly for 12 min, and then the pH was adjusted to 5.0 with 5 M NaOH to a light yellow transparent solution, and then anhydrous ethanol with a volume multiple of 3 times the volume of the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0066] b. Soak the cut filter paper in the copper nanocluster solution obtained in step a for 5 hours, and dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 365nm ultraviolet light;

[0067] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0068] c. Wipe the fluorescent test paper prepared in step b with the 2,4,6-trinitrotoluene (TNT) solid powder remaining in the suspicious plastic bag, and irradiate the fluorescent test paper with a portable ultraviolet lamp at 365 nm. It is found that the fluorescence is obviously quenched after the detection, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0069] d. After the prepared fluorescence test paper is quenched when detecting 2,4,6-trinitrotoluene (TNT), it can be soaked in acetonitrile for 1-5 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of repeatable fluorescence quenching.

[0070] Example 7

[0071] Preparation of fluorescent test strips:

[0072] a. At room temperature, 0.5 mL of 50 mM Cu(NO3)2 aqueous solution and 2.5 mL of 50 mM glutathione aqueous solution were measured and mixed evenly for 10 min, and then the pH was adjusted to 9.0 with 2 M NaOH to a light yellow transparent solution, and then anhydrous ethanol with a volume multiple of 9 times the volume of the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0073] b. Soak the cut filter paper in the copper nanocluster solution obtained in step a for 8 hours, and dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 365nm ultraviolet light;

[0074] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0075] c. Wipe the 2,4,6-trinitrotoluene (TNT) solid powder remaining in the suspicious device with the fluorescent test paper prepared in step b, and irradiate the fluorescent test paper with a portable ultraviolet lamp. It is found that the fluorescence is obviously quenched after the detection, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0076] d. After the prepared fluorescence test paper is quenched when detecting 2,4,6-trinitrotoluene (TNT), it can be immersed in acetonitrile for 3 seconds to restore strong orange fluorescence. The test paper with restored fluorescence continues to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of repeatable fluorescence quenching.

[0077] Example 8

[0078] Preparation of fluorescent test strips:

[0079] a. At room temperature, 0.5 mL of 50 mM Cu(NO3)2 aqueous solution and 2.5 mL of 50 mM glutathione aqueous solution were measured and mixed evenly for 14 min, and then the pH was adjusted to 8.0 with 3 M NaOH to a light yellow transparent solution, and then anhydrous ethanol with a volume multiple of 11.5 times the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0080] b. Soak the cut filter paper in the copper nanocluster solution obtained in step a for 10 hours, and then dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 365nm ultraviolet light;

[0081] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0082] c. Wipe the 2,4,6-trinitrotoluene (TNT) solid powder remaining in the suspicious device with the fluorescent test paper prepared in step b, and irradiate the fluorescent test paper with a portable ultraviolet lamp (330 nm). It is found that the fluorescence is obviously quenched after the detection, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0083] d. After the prepared fluorescence test paper is quenched when detecting 2,4,6-trinitrotoluene (TNT), it can be immersed in acetonitrile for 5 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface, realizing rapid detection of repeatable fluorescence quenching.

[0084] Example 9

[0085] Preparation of fluorescent test strips:

[0086] a. At room temperature, 0.5 mL of 50 mM Cu(NO3)2 aqueous solution and 2.5 mL of 50 mM glutathione aqueous solution were measured and mixed evenly for 2 min, and then the pH was adjusted to 7.0 with 4 M NaOH to a light yellow transparent solution, and then anhydrous ethanol with a volume multiple of 32.33 times the volume of the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0087] b. Soak the cut filter paper in the copper nanocluster solution obtained in step a for 10 hours, and then dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 365nm ultraviolet light;

[0088] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0089] c. Wipe the 2,4,6-trinitrotoluene (TNT) solid powder remaining in the suspicious device with the fluorescent test paper prepared in step b, and irradiate the fluorescent test paper with a portable ultraviolet lamp. It is found that the fluorescence is obviously quenched after the detection, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0090] d. After the prepared fluorescence test paper is quenched in TNT, it can be soaked in acetonitrile for 2 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface to achieve rapid detection of repeatable fluorescence quenching. Figure 3 .

[0091] Example 10

[0092] Preparation of fluorescent test strips:

[0093] a. At room temperature, 0.5 mL of 50 mM Cu(NO3)2 aqueous solution and 2.5 mL of 50 mM glutathione aqueous solution were measured and mixed evenly for 10 min, and then 2 mL of water was added to continue to disperse evenly, and the pH was adjusted to 4.0 with 3 M NaOH to a light yellow transparent solution, and then anhydrous ethanol with a volume multiple of 19 times the mixed solution of copper nitrate and glutathione was added to obtain a copper nanocluster solution;

[0094] b. Soak the cut filter paper in the copper nanocluster solution obtained in step a for 10 hours, and then dry it naturally to obtain a deposited fluorescent test paper, which can emit bright orange fluorescence under 365nm ultraviolet light;

[0095] Paper-based fluorescence detection of 2,4,6-trinitrotoluene:

[0096] c. Wipe the 2,4,6-trinitrotoluene (TNT) solid powder remaining on the surface of the suspicious object with the fluorescent test paper prepared in step b, and irradiate the fluorescent test paper with a portable ultraviolet lamp. It is found that the fluorescence is obviously quenched after the detection, thereby confirming the presence of 2,4,6-trinitrotoluene (TNT);

[0097] d. After the prepared fluorescence test paper is quenched in the detection of 2,4,6-trinitrotoluene (TNT), it can be soaked in acetonitrile for 4 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the 2,4,6-trinitrotoluene (TNT) powder residue on the solid surface, realizing rapid detection of repeatable fluorescence quenching, greatly reducing the detection cost, such as Figure 3 .

[0098] Although the above embodiments describe the present invention, it should be understood that the fluorescent test strip is also applicable to TNT detection in other fields without violating the spirit of the present invention. The ratio of reagent components and related condition parameters in the present invention can be appropriately adjusted, and these changes also fall within the scope of the present invention.

Claims

1. A method for repeatedly detecting 2,4,6-trinitrotoluene using a wipe-type fluorescent test paper, characterized in that The method first prepares a fluorescent test paper, and then uses the fluorescent test paper to wipe and detect 2,4,6-trinitrotoluene solid powder. The specific operation is carried out according to the following steps: Preparation of fluorescent test strips: a. At room temperature, a 10-100 mM copper nitrate aqueous solution and a 10-100 mM glutathione aqueous solution were stirred and uniformly mixed at a volume ratio of 1:3-1:7 for 1-15 min, and then a 0.5-5 M NaOH aqueous solution was used to adjust the pH to 4.0-9.0 to a light yellow transparent solution, and then anhydrous ethanol was added at a volume multiple of 2.33-49 times the volume of the mixed solution of copper nitrate and glutathione to obtain a copper nanocluster solution; b. Soak the cut filter paper in the copper cluster solution obtained in step a for 1-10 hours, and dry it naturally to obtain a deposited fluorescent test paper, which emits bright orange fluorescence under 365nm ultraviolet light; Paper-based fluorescence detection of 2,4,6-trinitrotoluene: c. Wipe the 2,4,6-trinitrotoluene solid powder remaining on the surface of the suspicious object with the fluorescent test paper prepared in step b, and the fluorescent test paper will be fluorescently quenched. Use a fluorescence spectrometer to scan the fluorescence emission spectrum before and after the fluorescent test paper detection, with the change in fluorescence intensity as the ordinate and the wavelength as the abscissa, to obtain the fluorescence emission spectrum before and after the fluorescent test paper detection for analysis and detection; Or use a portable ultraviolet lamp of 330-365 nm to directly illuminate the fluorescent test paper to achieve rapid naked eye identification and detection of suspicious scenes to determine the presence of 2,4,6-trinitrotoluene; d. After the prepared fluorescence test paper is quenched in TNT, it can be soaked in acetonitrile for 1-5 seconds to restore strong orange fluorescence. The test paper with restored fluorescence can continue to wipe the TNT powder residue on the solid surface to achieve rapid detection of repeated fluorescence quenching.

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