Identification method of isoylhydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation

Abstract

The present invention discloses a method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, comprising the following steps: 1. obtaining a GC-MS mass spectrum image of a suspected substance; 2. performing optical characterization (OCR) processing; 3. obtaining a mass-to-charge ratio sequence of all characteristic fragment ions of the suspected substance; 4. determining whether characteristic fragment ions with mass-to-charge ratios of 118, 132, and 146 are simultaneously present; if so, the suspected substance is considered to be an isocyanohydrazone synthetic cannabinoid, and the method proceeds to step 5; otherwise, the suspected substance is considered not to be an isocyanohydrazone synthetic cannabinoid, and the method proceeds to step 7; 5. determining whether the suspected substance contains a carbon chain, a carbon-carbon double bond, a carbon ring, a benzene ring, or a halogenated hydrocarbon structure based on the characteristic fragment ions in the suspected substance; 6. restoring the molecular structure of the suspected substance; and 7. ending the method. The present invention has the characteristics of rapidly and accurately identifying isocyanohydrazone synthetic cannabinoids.

Description

Technical Field

[0001] The present invention relates to the field of mass spectrometry image analysis, and in particular to a method for identifying isatoylhydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation. Background Art

[0002] The rapid evolution of synthetic cannabinoids, their diverse variety, and the lack of reference materials make structural identification of new synthetic cannabinoids challenging. Currently, there is no effective method for quickly and accurately identifying new isatoylhydrazone-based synthetic cannabinoids. This analysis relies primarily on the experience of the laboratory staff, which requires a high level of technical expertise, is time-consuming, and challenging, hindering the ability of forensic science laboratories to discover and identify new psychoactive substances. Summary of the Invention

[0003] The present invention aims to provide a method for identifying isatoylhydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation. The present invention has the characteristics of rapid and accurate identification of isatoylhydrazone synthetic cannabinoids.

[0004] The technical solution of the present invention is a method for identifying isatoylhydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, characterized by comprising the following steps:

[0005] Step 1: Using gas chromatography-mass spectrometry to obtain a mass spectrum image of the suspicious substance;

[0006] Step 2: Perform OCR processing on the mass spectrum image of the suspicious object to obtain the OCR recognition result;

[0007] Step 3: Determine the OCR recognition results, remove the numbers near the coordinate axis and the non-digital parts of the recognition, and obtain the mass-to-charge ratio sequence of all characteristic fragment ions of the suspicious object;

[0008] Step 4: Determine whether characteristic fragment ions with mass-to-charge ratios of m / z 118, m / z 132, and m / z 146 exist simultaneously in the mass-to-charge ratio sequence. If so, the suspected substance is considered to contain a 2-oxoindole nucleus and is an isocyanoylhydrazone synthetic cannabinoid, and proceed to step 5. Otherwise, the suspected substance is considered not to be an isocyanoylhydrazone synthetic cannabinoid, and proceed to step 7.

[0009] Step 5: Search the ion mass-to-charge ratio sequence to find the characteristic fragment ion with the mass-to-charge ratio closest to the maximum mass-to-charge ratio of -133, solve the equation, and determine whether the side chain of the 2-oxoindole core contains a carbon chain, a carbon-carbon double bond, a carbon ring, a benzene ring, or a halogenated hydrocarbon structure;

[0010] Step 6: Determine the side chain structure of the obtained 2-oxoindole core and infer the molecular structure of the reduced suspect;

[0011] Step 7: End the judgment.

[0012] In the aforementioned identification method of isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, step 2 is specifically as follows: the mass spectrum of the suspicious substance is used as the input of the OCR model, OCR processing is performed, and the final output is the OCR recognition result, which is a series of predicted sequences P={ P 1, P 2,..., P m} (m is a positive integer).

[0013] In the aforementioned method for identifying isatoylhydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, step three specifically includes the following steps:

[0014] 3.1. Traverse the prediction sequence P, remove the prediction results containing non-digital content and the prediction results near the image coordinate axis, and obtain the mass-to-charge ratio sequence D of the characteristic fragment ions = { D 1, D 2,..., D n} (n is a positive integer, n≤m), for any two fragments in the mass-to-charge ratio sequence D D i and D j (0﹤i﹤j≤n, and i and j are both positive integers), D i ≠ D j ;

[0015] 3.2. Sort the mass-to-charge ratio sequence D in ascending order to obtain the mass-to-charge ratio sequence C={ C 1, C 2,..., C n} (n is a positive integer), for any two fragments in the mass-to-charge ratio sequence C C i and C j (0﹤i﹤j≤n, and i and j are both positive integers), C i ≠ C j .

[0016] In the aforementioned method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, step four specifically includes the following steps:

[0017] 4.1, remember x =0, y =0, z =0;

[0018] 4.2. Traverse the ion mass-to-charge ratio sequence C. If there are fragments C i =118 (0﹤i≤n, i is a positive integer), then x =1, go to step 4.3; otherwise go to step 4.5;

[0019] 4.3. Traverse the ion mass-to-charge ratio sequence C. If there are fragments C i =132 (0﹤i≤n, i is a positive integer), then y =1, go to step 4.4; otherwise go to step 4.5;

[0020] 4.4. Traverse the ion mass-to-charge ratio sequence C. If there are fragments C i =146 (0﹤i≤n, i is a positive integer), then record z =1; go to step 4.5;

[0021] 4.5 Calculation x 、 y 、 z Is the product value equal to 1? If it is equal to 1, it is considered that the suspicious substance contains a 2-oxoindole mother nucleus and is an isocyanoylhydrazone synthetic cannabinoid, and go to step 5; if it is not equal to 1, it is considered that the suspicious substance is not an isocyanoylhydrazone synthetic cannabinoid, and go to step 7.

[0022] In the aforementioned method for identifying isatoylhydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, step five specifically includes the following steps:

[0023] 5.1. Search the ion mass-to-charge ratio sequence C and find the closest mass-to-charge ratio value. C n -133 fragments C i (0﹤i≤n, i is a positive integer), solve the equation: 12 u +14 w +13 x +18 y +34 z +132= C i ( u,y,z is 0 or 1, w, x, are all non-negative integers);

[0024] 5.2 If C i If the corresponding equation (0﹤i≤n, i is a positive integer) has no solution, then the only possible conclusion is that the suspected substance is an isocyanohydrazone synthetic cannabinoid;

[0025] 5.3 If C iThe solution of the equation corresponding to (0﹤i≤n, i is a positive integer) u + x ﹥0, w ﹥0, and there is no C j =C i -28 (0 < j < i ≤ n, i, j are positive integers), then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus is first connected to a carbon chain, and there is a carbon ring at the end of the carbon chain. The number of carbon atoms in the carbon ring is u + x + w -1;

[0026] 5.4 If C i The solution of the equation corresponding to (0﹤i≤n, i is a positive integer) u + x ﹥0, w ﹥0, and there exists C j =C i -28 (0 < j < i ≤ n, i, j are positive integers), then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus is first connected to a carbon chain, and there is a carbon-carbon double bond at the end of the carbon chain;

[0027] 5.5 If the equation solution is u =0, w ﹥0, x =0, then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus has a carbon chain, w is the number of carbon atoms on the carbon chain;

[0028] 5.6 If the equation solution is x ≥6, then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus has a benzene ring;

[0029] 5.7 If the equation solution is y ﹥0, and there exists C j = C i -20 (0 < j < i ≤ n, i, j are positive integers), then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus has fluorine; [[ID=�2]]

[0030] 5.8 If the equation solution is z﹥0, and there exists C j =C i -36 (0 < j < i ≤ n, i, j are positive integers), then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus has chlorine.

[0031] In the aforementioned method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, step six is specifically as follows: C i (0≤i≤n, i is a positive integer) Solve the equation and determine the priority of the side chain connection of the 2-oxoindole mother nucleus, determine the side chain structure of the 2-oxoindole mother nucleus, and infer the molecular structure of the reduced suspect.

[0032] In the aforementioned identification method of isatoylhydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, the priority order of the side chain connection of the 2-oxoindole parent nucleus is: carbon chain > carbon ring or benzene ring > carbon-carbon double bond > fluorine or chlorine.

[0033] Suspected substances are processed using a gas chromatography-mass spectrometer. Combining the high separation capabilities of chromatography with the high sensitivity and rich structural information of mass spectrometry, this method is suitable for rapid screening of target substances in complex mixtures. Mass spectrometry is an excellent method for determining atomic mass, relative isotope abundance, electron collision processes, and analyzing complex organic compound mixtures. It offers high accuracy, rapid analysis, and high sensitivity.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention primarily applies the mass spectrometry fragmentation patterns of novel isatoylhydrazone-based synthetic cannabinoids to the structural analysis of such synthetic cannabinoids through computer language. Based on the mass spectrometry results, the molecular structure of suspected substances can be rapidly and directly inferred and identified. This addresses the difficulty in identifying such synthetic cannabinoids, which is caused by the rapid update and variety of novel isatoylhydrazone-based synthetic cannabinoids, the lack of standards, the high price of standards (10 mg / 8,000 yuan), and the difficulty in purchasing them. Furthermore, the present invention can reduce human intervention, lower identification costs, and the entry threshold for laboratory technicians, thereby improving work efficiency.

[0036] 2. Isatoylhydrazone synthetic cannabinoids are analyzed using gas chromatography-mass spectrometry in electron impact mass spectrometry mode, which can obtain more characteristic fragment ions with high reproducibility, and can more accurately determine the structure of isatoylhydrazone synthetic cannabinoids in complex suspicious substances;

[0037] 3. Existing on-site rapid detection equipment all establishes a standard database based on existing standards. Rapid detection at the scene of an investigation is achieved by comparing the substance being tested with the standard database. This invention will be further deeply integrated with the operating software of portable gas chromatography-mass spectrometry instruments such as Puyu, Yingfukang, and PE. In the absence of a standard database, this method can achieve rapid, real-time automated detection and structural confirmation of such synthetic cannabinoids at the scene of an investigation. It can also provide a method for rapid screening of new isatoylhydrazone-based synthetic cannabinoids in the judicial field. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the process of the present invention;

[0039] Figure 2 This is the GC-MS mass spectrum result of MDA-19;

[0040] Figure 3 for Figure 2 OCR recognition result diagram;

[0041] Figure 4 is the cleavage diagram of MDA-19;

[0042] Figure 5 is the cleavage diagram of CHM-MDA-19;

[0043] Figure 6 This is the GC-MS mass spectrometry result of CHM-MDA-19;

[0044] Figure 7 is the cleavage diagram of 4en MDA-19;

[0045] Figure 8 This is the cleavage diagram of 5F-MDA-19. DETAILED DESCRIPTION

[0046] The present invention will be further described below with reference to the examples, but they are not intended to limit the present invention.

[0047] A method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation comprises the following steps:

[0048] Step 1: Use gas chromatography-mass spectrometry to obtain a mass spectrum image of the suspicious object.

[0049] Step 2: Take the mass spectrum of the suspicious object as the input of the OCR model, perform OCR processing, and finally output the OCR recognition result, which is a series of prediction sequences P={ P 1, P 2,..., P m} (where m is a positive integer).

[0050] Step 3: Determine the OCR recognition results, remove the numbers near the coordinate axis and the recognized non-digital parts, and obtain the mass-to-charge ratio sequence of all characteristic fragment ions of the suspicious object; specifically, the following steps are included:

[0051] 3.1. Traverse the prediction sequence P, judge the OCR recognition results, eliminate the prediction results containing non-digital content and the prediction results near the image coordinate axis, and obtain the mass-to-charge ratio sequence D of the characteristic fragment ions = { D 1, D 2,...,D n} (n is a positive integer, n≤m), for any two fragments in the mass-to-charge ratio sequence D D i and D j (0﹤i﹤j≤n, and i and j are both positive integers), D i ≠ D j ;

[0052] 3.2. Sort the mass-to-charge ratio sequence D in ascending order to obtain the mass-to-charge ratio sequence C={ C 1, C 2,..., C n} (n is a positive integer), for any two fragments in the mass-to-charge ratio sequence C C i and C j (0﹤i﹤j≤n, and i and j are both positive integers), C i ≠ C j .

[0053] Step 4: Determine whether characteristic fragment ions with mass-to-charge ratios of m / z 118, m / z 132, and m / z 146 exist simultaneously in the mass-to-charge ratio sequence. If so, the suspected substance is considered to contain a 2-oxoindole nucleus and is an isocyanoylhydrazone synthetic cannabinoid, and proceed to step 5. Otherwise, the suspected substance is considered not to be an isocyanoylhydrazone synthetic cannabinoid, and proceed to step 7.

[0054] The specific steps include:

[0055] 4.1, remember x =0, y =0, z =0;

[0056] 4.2. Traverse the ion mass-to-charge ratio sequence C. If there are fragments C i =118 (0﹤i≤n, i is a positive integer), then x =1, go to step 4.3; otherwise go to step 4.5;

[0057] 4.3. Traverse the ion mass-to-charge ratio sequence C. If there are fragments C i =132 (0﹤i≤n, i is a positive integer), then y =1, go to step 4.4; otherwise go to step 4.5;

[0058] 4.4. Traverse the ion mass-to-charge ratio sequence C. If there is a fragment C i = 146 (0 < i ≤ n, i is a positive integer), then record z = 1; go to step 4.5;

[0059] 4.5. Calculate whether the product value of x 、 y 、 z is equal to 1. If it is equal to 1, it is considered that the suspicious substance contains a 2-oxoindole nucleus and is an isatin acylhydrazone synthetic cannabinoid, and go to step five; if it is not equal to 1, it is considered that the suspicious substance is not an isatin acylhydrazone synthetic cannabinoid, and go to step seven.

[0060] Step five: For the characteristic fragment ion with the mass-to-charge ratio value closest to the maximum mass-to-charge ratio - 133, solve the equation to determine whether there are carbon chains, carbon-carbon double bonds, carbon rings, benzene rings or halogenated hydrocarbon structures in the side chain of the 2-oxoindole nucleus;

[0061] Specifically, it includes the following steps:

[0062] 5.1. Search the ion mass-to-charge ratio sequence C to find the fragment with the mass-to-charge ratio value closest to C n - 133 (0 < i ≤ n, i is a positive integer), and solve the equation: 12 C i + 14 u + 13 w + 18 x + 34 y + 132 = z + 132 = C i ( u,y,z is 0 or 1, w, x, both are non-negative integers);

[0063] 5.2 If the equation corresponding to C i (0 < i ≤ n, i is a positive integer) has no solution, then it can only be judged that the suspicious substance is an isatin acylhydrazone synthetic cannabinoid;

[0064] 5.3 If the equation corresponding to C i (0 < i ≤ n, i is a positive integer) gives a solution of u + x > 0, w > 0, and there is no C j =C i - 28 (0 < j < i ≤ n, i, j are positive integers), then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus is first connected to a carbon chain, and there is a carbon ring at the end of the carbon chain. The carbon content of the carbon ring isu + x + w -1;

[0065] 5.4 If C i the solution of the equation corresponding to (0 < i ≤ n, i is a positive integer) is u + x > 0, w > 0, and there exists C j =C i -28 (0 < j < i ≤ n, i, j are positive integers), then the structural formula of the suspect is that the side chain of the 2-oxoindole nucleus is first connected to a carbon chain, and there is a carbon-carbon double bond at the end of the carbon chain;

[0066] 5.5 If the equation solution is u = 0, w > 0, x = 0, then the structural formula of the suspect is that the side chain of the 2-oxoindole nucleus has a carbon chain, w is the number of carbon atoms on the carbon chain;

[0067] 5.6 If the equation solution is x ≥ 6, then the structural formula of the suspect is that the side chain of the 2-oxoindole nucleus has a benzene ring;

[0068] 5.7 If the equation solution is y > 0, and there exists C j = C i -20 (0 < j < i ≤ n, i, j are positive integers), then the structural formula of the suspect is that the side chain of the 2-oxoindole nucleus has fluorine;

[0069] 5.8 If the equation solution is z > 0, and there exists C j =C i -36 (0 < j < i ≤ n, i, j are positive integers), then the structural formula of the suspect is that the side chain of the 2-oxoindole nucleus has chlorine.

[0070] Step Six: According to the result of solving the equation for the fragment C i (0 ≤ i ≤ n, i is a positive integer) and the priority order of the connection of the side chain of the 2-oxoindole nucleus, judge the structure of the side chain of the 2-oxoindole nucleus obtained, and infer the molecular structure of the reduced suspect. The priority order of the connection of the side chain of the 2-oxoindole nucleus is: carbon chain > carbon ring or benzene ring > carbon-carbon double bond > fluorine or chlorine.

[0071] Step Seven: End the determination.

[0072] Example 1:

[0073] A method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation Figure 2 Take MDA-19 as an example, combined with Figure 1 The present invention is further described in detail. The selected OCR model takes the CTPN model as an example, which can effectively detect horizontally distributed text in complex scenes.

[0074] The following steps are involved:

[0075] Step 1: Use gas chromatography-mass spectrometry to obtain the mass spectrum image of the suspicious object; Figure 2 As shown in the figure, this image is the GC-MS mass spectrum result of MDA-19. The horizontal axis represents the mass-to-charge ratio (m / z) value of the ion. The mass-to-charge ratio value increases from left to right. For ions with a single charge, the value represented by the horizontal axis is the mass of the ion; the vertical axis represents the relative intensity of the ion peak.

[0076] Step 2: The mass spectrum of the suspicious object is used as the input of the OCR (Optical Character Recognition) model, and OCR processing is performed. The final output is the OCR recognition result, which is a series of prediction sequences P = { P 1, P 2,..., P m} (where m is a positive integer).

[0077] Each prediction sequence P i (0 < i ≤ m, i is a positive integer) contains the coordinate position of the predicted box and the text content. The coordinate position includes the coordinates of the upper left corner and the lower right corner of the predicted box. For example, P = {100, 100, 200, 200, "123"}, which means that the coordinates of the upper left corner of the predicted box are (100, 100), the coordinates of the lower right corner are (200, 200), and the text content is "123";

[0078] Will Figure 3 The GC-MS mass spectrum result of MDA-19 was processed by OCR according to the above method, and the OCR recognition result was obtained as follows Figure 3 As shown, Figure 3 The location of the Chinese characters is Figure 2 Identify the corresponding position.

[0079] Step 3:

[0080] 3.1. Traverse the predicted sequence P, identify the OCR recognition results, remove the numbers near the coordinate axis and the recognized non-digital parts, and obtain the mass-to-charge ratio sequence D = {105, 244, 118, 51, 55, 77, 132, 146, 159, 188, 216, 229, 274, 281, 321, 341, 349} (n = 17) of all characteristic fragment ions of the suspicious object;

[0081] 3.2. Sort the mass-to-charge ratio sequence D in ascending order to obtain the mass-to-charge ratio sequence of characteristic fragment ions C = {51, 55, 77, 105, 118, 132, 146, 159, 188, 216, 229, 244, 274, 281, 321, 341, 349} (n = 17).

[0082] Step 4:

[0083] 4.1, remember x =0, y =0, z =0;

[0084] 4.2. Traverse the ion mass-to-charge ratio sequence C and find fragments C 5=118, then record x =1, go to step 4.3;

[0085] 4.3. Traverse the ion mass-to-charge ratio sequence C and find fragments C 6=132, then record y =1, go to step 4.4;

[0086] 4.4. Traverse the ion mass-to-charge ratio sequence C and find fragments C 7=146, then record z =1;

[0087] 4.5 Calculation x × y × z =1, the suspicious substance is considered to contain a 2-oxoindole nucleus and is an isatoacylhydrazone synthetic cannabinoid, and the procedure is to go to step five.

[0088] Step 5: Search the ion mass-to-charge ratio sequence C and find the ion with the mass-to-charge ratio closest to C. 17 -133=349-133=216 fragments C i ,Right now C 10 .right C 10 =216 Solve the equation, the equation is: 12 u +14 w +13 x +18y +34 z +132=216; among them, 12=the mass-to-nuclear ratio of carbon atom, 14=the mass-to-nuclear ratio of CH2, 13=the mass-to-nuclear ratio of CH, 18=the mass-to-nuclear ratio of fluorine -1, 34=the mass-to-nuclear ratio of chlorine -1. w Indicates the amount of CH2, x Indicates the number of CHs.

[0089] The solution is u =0, w =6, x =0, y =0, z =0, and there is no other integer solution, which meets the judgment condition 5.5. That is, the side chain of the 2-oxoindole core is C6H 12 , which is CH2CHCH2CH2CH2CH3, and does not contain benzene ring structure or halogenated hydrocarbon structure.

[0090] Step 6: After solving the equation, we know that the 2-oxoindole core can be connected to a carbon chain of C6H at most. 12 , does not contain benzene ring structure, halogenated hydrocarbon structure, then the structural formula of the suspicious substance is restored as follows Figure 4 shown.

[0091] Step 7: End the judgment.

[0092] Example 2:

[0093] A method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, taking CHM-MDA-19 as an example, combined with Figure 1 The present invention is further described in detail. The selected OCR model takes the CTPN model as an example, which can effectively detect horizontally distributed text in complex scenes.

[0094] The following steps are involved:

[0095] Step 1: Use gas chromatography-mass spectrometry to obtain GC-MS mass spectrum images of suspicious substances. Figure 6 shown.

[0096] Step 2: The mass spectrum of the suspicious object is used as the input of the OCR (Optical Character Recognition) model, and OCR processing is performed. The final output is the OCR recognition result, which is a series of prediction sequences P = { P 1, P 2,..., P m} (where m is a positive integer).

[0097] Step 3:

[0098] 3.1. Traverse the predicted sequence P, identify the OCR recognition results, remove the numbers near the coordinate axis and the recognized non-digital parts, and obtain the mass-to-charge ratio sequence D = {361, 256, 228, 118, 132, 105, 146, 77} (n = 8) of all characteristic fragment ions of the suspicious object;

[0099] 3.2. Sort the mass-to-charge ratio sequence D in ascending order to obtain the mass-to-charge ratio sequence of characteristic fragment ions C = {77, 105, 118, 132, 146, 228, 256, 361} (n = 8).

[0100] Step 4:

[0101] 4.1, remember x =0, y =0, z =0;

[0102] 4.2. Traverse the ion mass-to-charge ratio sequence C and find fragments C 3=118, then record x =1, go to step 4.3;

[0103] 4.3. Traverse the ion mass-to-charge ratio sequence C and find fragments C 4=132, then y =1, go to step 4.4;

[0104] 4.4. Traverse the ion mass-to-charge ratio sequence C and find fragments C 5=146, then record z =1;

[0105] 4.5 Calculation x × y × z =1, the suspicious substance is considered to contain a 2-oxoindole nucleus and is an isatoacylhydrazone synthetic cannabinoid, and the procedure is to go to step five.

[0106] Step 5: Search the ion mass-to-charge ratio sequence C and find the fragment with the mass-to-charge ratio closest to C8-133=361-133=228, that is, C 6. Right C 6=228 Solve the equation, the equation is: 12 u +14 w +13 x +18 y +34 z +132=228; where 12=mass-to-nuclear ratio of carbon atoms, 14=mass-to-nuclear ratio of CH2, 13=mass-to-nuclear ratio of CH, 18=mass-to-nuclear ratio of fluorine -1, 34=mass-to-nuclear ratio of chlorine -1, w Indicates the amount of CH2,x Indicates the number of CHs.

[0107] We can get two sets of non-negative integer solutions, one of which is u =0, w =0, x =6, y =1, z =0, because it does not exist C j =C i The fragments of -20=228-20=208 meet the criteria of 5.6 on benzene ring in the manual, and it is confirmed that the side chain contains a benzene ring; the other group is u =0, w =5, x =2, y =0, z =0, and does not exist C j =228-28=200 fragments meet the judgment criteria of 5.3 in the manual, and determine that the side chain is first connected to a carbon and then to a carbon ring.

[0108] Since the carbon chain has a higher priority than the benzene ring, the second solution is chosen.

[0109] Step 6: After solving the equation, we know that the side link of the 2-oxoindole core is C7H 14 , first connect CH2 and then C6H 12 (cyclohexane), does not contain benzene ring structure, halogenated hydrocarbon structure, then the structural formula of the suspicious substance is restored as follows Figure 5 shown.

[0110] Step 7: End the judgment.

[0111] Example 3:

[0112] A method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, taking 4en MDA-19 as an example, combined with Figure 1 The present invention is further described in detail. The selected OCR model takes the CTPN model as an example, which can effectively detect horizontally distributed text in complex scenes.

[0113] The following steps are involved:

[0114] Step 1: Use gas chromatography-mass spectrometry to obtain a GC-MS mass spectrum image of the suspicious substance.

[0115] Step 2: The mass spectrum of the suspicious object is used as the input of the OCR (Optical Character Recognition) model, and OCR processing is performed. The final output is the OCR recognition result, which is a series of prediction sequences P = { P 1, P 2,..., P m} (where m is a positive integer).

[0116] Step 3:

[0117] 3.1. Discriminate the OCR recognition results, remove the numbers near the coordinate axis and the non-digital parts of the recognition, and obtain the mass-to-charge ratio sequence D = {77, 105, 146, 333, 132, 228, 200, 172, 118} (n = 9) of all characteristic fragment ions of the suspicious object;

[0118] 3.2. Sort the mass-to-charge ratio sequence D in ascending order to obtain the mass-to-charge ratio sequence of characteristic fragment ions C = {77, 105, 118, 132, 146, 172, 200, 228, 333} (n = 9);

[0119] Step 4:

[0120] 4.1, remember x =0, y =0, z =0;

[0121] 4.2. Traverse the ion mass-to-charge ratio sequence C and find fragments C 3=118, then record x =1, go to step 4.3;

[0122] 4.3. Traverse the ion mass-to-charge ratio sequence C and find fragments C 4=132, then y =1, go to step 4.4;

[0123] 4.4. Traverse the ion mass-to-charge ratio sequence C and find fragments C 5=146, then record z =1;

[0124] 4.5 Calculation x × y × z =1, the suspicious substance is considered to contain a 2-oxoindole nucleus and is an isatoacylhydrazone synthetic cannabinoid, and the procedure is to go to step five.

[0125] Step 5. Search the ion mass-to-charge ratio sequence C and find the fragment with the mass-to-charge ratio closest to C9-133=333-133=200, which is C7. Solve the equation for C7=200, and the equation is: 12 u +14 w +13 x +18 y +34 z +132=200; where 12=mass-to-nuclear ratio of carbon, 14=mass-to-nuclear ratio of CH2, 13=mass-to-nuclear ratio of CH, 18=mass-to-nuclear ratio of fluorine -1, 34=mass-to-nuclear ratio of chlorine -1, w Indicates the amount of CH2, x Indicates the number of CHs.

[0126] The solution is u =0, w =3, x =2, y =0, z =0, u + x =2﹥0, w =3﹥0, x > 0, and C6 = 200 - 28 = 172, meeting criteria 5.4. Further cleavage of C7 results in the loss of a carbon chain containing a double bond. This means the side chain of the 2-oxoindole nucleus is C5H8, or CH2CHCH2CHCH2, without a benzene ring or halogenated hydrocarbon structure.

[0127] Step 6. After solving the equation, we know that the 2-oxoindole core can be connected to a carbon chain of C5H8 at most, and does not contain a benzene ring structure or a halogenated hydrocarbon structure. The structural formula of the suspected compound is restored as follows: Figure 7 shown.

[0128] Step 7: End the judgment.

[0129] Example 4:

[0130] A method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, taking 5F-MDA-19 as an example, combined with Figure 1 The present invention is further described in detail. The selected OCR model takes the CTPN model as an example, which can effectively detect horizontally distributed text in complex scenes.

[0131] The following steps are involved:

[0132] Step 1: Use gas chromatography-mass spectrometry to obtain a GC-MS mass spectrum image of the suspicious substance.

[0133] Step 2: The mass spectrum of the suspicious object is used as the input of the OCR (Optical Character Recognition) model, and OCR processing is performed. The final output is the OCR recognition result, which is a series of prediction sequences P = { P 1, P 2,..., P m} (where m is a positive integer).

[0134] Step 3:

[0135] 3.1. Traverse the predicted sequence P, identify the OCR recognition results, remove the numbers near the coordinate axis and the recognized non-digital parts, and obtain the mass-to-charge ratio sequence D = {77, 105, 146, 353, 132, 248, 220, 200, 172, 118} (n = 10) of all characteristic fragment ions of the suspicious object;

[0136] 3.2. Sort the mass-to-charge ratio sequence D from small to large, and obtain the mass-to-charge ratio sequence of characteristic fragment ions C = {77, 105, 118, 132, 146, 172, 200, 220, 248, 353} (n = 10).

[0137] Step 4:

[0138] 4.1, remember x =0, y =0, z =0;

[0139] 4.2. Traverse the ion mass-to-charge ratio sequence C and find fragments C 3=118, then record x =1, go to step 4.3;

[0140] 4.3. Traverse the ion mass-to-charge ratio sequence C and find fragments C 4=132, then y =1, go to step 4.4;

[0141] 4.4. Traverse the ion mass-to-charge ratio sequence C and find fragments C 5=146, then record z =1;

[0142] 4.5 Calculation x × y × z =1, the suspicious substance is considered to contain a 2-oxoindole nucleus and is an isatoacylhydrazone synthetic cannabinoid, and the procedure is to go to step five.

[0143] Step 5: Search the ion mass-to-charge ratio sequence C and find the ion with the mass-to-charge ratio closest to C.10 -133 = 353 - 133 = 220's fragment, that is, C8. Solve the equation for C8 = 220, the equation is: 12 u +14 w +13 x +18 y +34 z +132 =​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​= 0. According to the solution of C7=200, it is shown that the fragment lost from C8 to C7 is HF with a mass-to-charge ratio of 20. If the side chain contains Cl with a mass-to-charge ratio of 35, then the fragment C7 cannot exist. w =3, x =2 also confirms that there should be 5 carbons, not 4, leaving only one set of solutions.

[0146] Therefore, the side chain of the 2-oxoindole nucleus is C5H 10 F is CH2CH2CH2CH2CH2F and does not contain a benzene ring structure or chlorine.

[0147] Step 6: After solving the equation, we know that the 2-oxoindole core can be connected to a carbon chain C5H 10 F, does not contain benzene ring structure, halogenated hydrocarbon structure, then the structural formula of the suspicious substance is restored as follows Figure 8 shown.

[0148] Step 7: End the judgment.

Claims

1. A method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation, characterized in that: The following steps are involved: Step 1: Using gas chromatography-mass spectrometry to obtain a mass spectrum image of the suspicious substance; Step 2: Perform OCR processing on the mass spectrum image of the suspicious object to obtain the OCR recognition result; Step 3: Determine the OCR recognition results, remove the numbers near the coordinate axis and the non-digital parts of the recognition, and obtain the mass-to-charge ratio sequence of all characteristic fragment ions of the suspicious object; Step 4: Determine whether characteristic fragment ions with mass-to-charge ratios of m / z 118, m / z 132, and m / z 146 exist simultaneously in the mass-to-charge ratio sequence. If so, the suspected substance is considered to contain a 2-oxoindole nucleus and is an isocyanoylhydrazone synthetic cannabinoid, and proceed to step 5. Otherwise, the suspected substance is considered not to be an isocyanoylhydrazone synthetic cannabinoid, and proceed to step 7. Step 5: Solve the equation for the characteristic fragment ions with mass-to-charge ratio values closest to the maximum mass-to-charge ratio of -133 to determine whether the side chain of the 2-oxoindole core contains a carbon chain, a carbon-carbon double bond, a carbon ring, a benzene ring, or a halogenated hydrocarbon structure; Specifically, the following steps are included: 5.

1. Search the ion mass-to-charge ratio sequence C and find the mass-to-charge ratio value closest to C n -133 fragments C i , 0﹤i≤n, i is a positive integer, solve the equation: 12 u +14 w +13 x +18 y +34 z +132= C i , u,y,z is 0 or 1, w, x, are all non-negative integers; 5.2 If C i , 0﹤i≤n, i is a positive integer, and the corresponding equation has no solution, then we can only judge that the suspicious substance is an isocyanohydrazone synthetic cannabinoid; 5.3 If C i , 0 < i ≤ n, i is a positive integer, and the corresponding equation solution gives u + x > 0, w > 0, and there does not exist C j =C i -28, 0 < j < i ≤ n, i, j are positive integers, then the structural formula of the suspect is that the side chain of the 2-oxoindole nucleus is first connected to a carbon chain, and there is a carbon ring at the end of the carbon chain, and the number of carbon atoms in the carbon ring is u + x + w -1; 5.4 If C i , 0 < i ≤ n, i is a positive integer, and the corresponding equation solution is u + x > 0, w > 0, and there exists C j =C i -28, 0 < j < i ≤ n, i and j are positive integers, then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus is first connected to a carbon chain, and there is a carbon-carbon double bond at the end of the carbon chain; 5.5 If the equation is solved u =0, w ﹥0, x=0, then the structural formula of the suspected substance is 2-oxoindole, the side chain of the mother nucleus has a carbon chain, w is the number of carbon atoms in the carbon chain; 5.6 If the equation is solved x ≥6, the structural formula of the suspected substance is a 2-oxoindole nucleus with a benzene ring on the side chain; 5.7 If the solution of the equation is y ﹥0, and there exists C j = C i -20, 0 < j < i ≤ n, i and j are positive integers, then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus has fluorine; 5.8 If the solution of the equation gives z > 0, and there exists C j =C i -36, 0 < j < i ≤ n, where i and j are positive integers, then the structural formula of the suspicious substance is that the side chain of the 2-oxoindole nucleus has chlorine; Step 6: Based on the fragments C i , 0≤i≤n, i is a positive integer, the result of solving the equation and the priority order of the side chain connection of the 2-oxoindole mother nucleus, where the priority order of the side chain connection of the 2-oxoindole mother nucleus is: carbon chain > carbon ring or benzene ring > carbon-carbon double bond > fluorine or chlorine; determine the side chain structure of the obtained 2-oxoindole mother nucleus and infer the molecular structure of the reduced suspect; Step 7: End the judgment.

2. The method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation according to claim 1, characterized in that: Step 2 is as follows: take the mass spectrum of the suspicious object as the input of the OCR model, perform OCR processing, and finally output the OCR recognition result, which is a series of prediction sequences P={ P 1, P 2,..., P m }, where m is a positive integer.

3. The method for identifying isatoylhydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation according to claim 2, characterized in that: Step three specifically includes the following steps: 3.

1. Traverse the prediction sequence P, judge the OCR recognition results, eliminate the prediction results containing non-digital content and the prediction results near the image coordinate axis, and obtain the mass-to-charge ratio sequence D of the characteristic fragment ions = { D 1, D 2,..., D n }, n is a positive integer, n≤m, for any two fragments in the mass-to-charge ratio sequence D D i and D j , 0﹤i﹤j≤n, and i and j are both positive integers, D i ≠ D j ; 3.

2. Sort the mass-to-charge ratio sequence D in ascending order to obtain the mass-to-charge ratio sequence C={ C 1, C 2,..., C n }, n is a positive integer, for any two fragments in the mass-to-charge ratio sequence C C i and C j , 0﹤i﹤j≤n, and i and j are both positive integers, C i ≠ C j .

4. The method for identifying isocyanohydrazone synthetic cannabinoids based on gas chromatography-mass spectrometry fragmentation according to claim 3, characterized in that: Step 4 specifically includes the following steps: 4.1, remember x =0, y =0, z =0; 4.

2. Traverse the ion mass-to-charge ratio sequence C. If there are fragments C i =118, 0﹤i≤n, i is a positive integer, then record x =1, go to step 4.3; otherwise go to step 4.5; 4.

3. Traverse the ion mass-to-charge ratio sequence C. If there are fragments C i =132, 0﹤i≤n, i is a positive integer, then record y =1, go to step 4.4; otherwise go to step 4.5; 4.

4. Traverse the ion mass-to-charge ratio sequence C. If there are fragments C i =146, 0﹤i≤n, i is a positive integer, then record z =1; go to step 4.5; 4.5 Calculation x 、 y 、 z Is the product value equal to 1? If it is equal to 1, it is considered that the suspicious substance contains a 2-oxoindole mother nucleus and is an isocyanoylhydrazone synthetic cannabinoid, and go to step 5; if it is not equal to 1, it is considered that the suspicious substance is not an isocyanoylhydrazone synthetic cannabinoid, and go to step 7.

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