A method for identifying synthetic cannabinoids using terahertz spectroscopy.

Abstract

This invention relates to a method for identifying synthetic cannabinoids using terahertz spectroscopy. The method involves acquiring the terahertz absorption spectrum of the sample to be tested, extracting characteristic absorption peak parameters (including one or more of the following: peak position, peak position combination, number of characteristic peaks, and local peak shape distribution); comparing these parameters with preset standard characteristic absorption peaks of the target synthetic cannabinoid to determine whether the sample is the target synthetic cannabinoid. This method requires small sample volumes, has simple pretreatment, and is fast, making it suitable for rapid screening and preliminary identification of synthetic cannabinoids.

Description

Technical Field

[0001] This invention belongs to the field of substance detection, and specifically relates to a method for identifying synthetic cannabinoids using terahertz spectroscopy. Background Technology

[0002] New psychoactive substances (NPS) have become a significant challenge in drug control and public safety in recent years. These substances are typically obtained by locally modifying the chemical structure of controlled substances, and are characterized by rapid emergence of new species, strong structural similarity, and high concealment, posing considerable challenges to on-site screening, laboratory identification, and regulatory enforcement. Among them, synthetic cannabinoids are an important class of NPS. They usually produce psychoactive effects similar to natural cannabinoids by acting on cannabinoid receptors. However, some synthetic cannabinoids have stronger receptor affinity and higher health risks, and abuse can lead to severe acute poisoning and public health hazards.

[0003] Synthetic cannabinoids possess complex structures, commonly including structural units such as indole, indazole, amide, ester, alkyl chain, haloaryl, or cycloalkyl substituents. Because these substances can be rapidly derived by altering the parent nucleus, side chains, linking groups, or substituents, novel analogs are constantly emerging. Different synthetic cannabinoids may differ only in local substituents or side chains in their molecular structure, but their legal attributes, toxicological risks, and regulatory implications can vary. Therefore, establishing a method for rapid screening of test samples and distinguishing target synthetic cannabinoids has significant practical value.

[0004] Currently, the main methods for detecting synthetic cannabinoids include gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography (HPLC), liquid chromatography-mass spectrometry (LC-MS), infrared spectroscopy, Raman spectroscopy, and nuclear magnetic resonance (NMR). Chromatography-mass spectrometry (GC-MS) offers high sensitivity and qualitative capabilities, making it a common tool in laboratory confirmatory analysis. However, these methods typically require sample extraction, solvent treatment, chromatographic separation, and mass spectrometric analysis, demanding high-level instrumentation and operational expertise, and resulting in relatively long detection cycles. This makes it difficult to fully meet the needs of rapid on-site screening and batch initial screening.

[0005] Vibrational spectroscopy methods such as infrared spectroscopy and Raman spectroscopy have advantages such as relatively simple operation, fast detection speed, and low sample consumption, and can be used for rapid screening of some drugs and new psychoactive substances. However, for synthetic cannabinoids with similar structures and small differences in substituents, conventional vibrational spectroscopy may have problems such as peak overlap or insufficiently intuitive characteristic differences in some regions. Especially in the case of rapid identification of complex matrices or suspicious samples, it may be difficult to obtain stable distinctions by relying solely on a single peak or local spectral information.

[0006] Terahertz spectroscopy, located between microwaves and infrared, can reflect information such as low-frequency molecular vibrations, lattice vibrations, intermolecular interactions, and collective vibrational modes in solid samples. For solid small molecule compounds, terahertz absorption spectra are often related to their molecular structure, substituent differences, crystal packing patterns, and intermolecular interactions, thus possessing certain "fingerprint" identification potential. Compared with traditional confirmatory methods, terahertz spectroscopy detection has the advantages of relatively simple sample pretreatment, fast detection speed, small sample volume, and good non-destructive properties, making it suitable for rapid screening and preliminary identification of suspicious samples.

[0007] However, existing terahertz spectroscopy methods for identifying synthetic cannabinoids remain relatively limited, particularly lacking a technical solution for distinguishing structurally similar synthetic cannabinoids based on characteristic absorption peak positions and combinations within specific frequency bands. Therefore, it is necessary to establish a method for identifying synthetic cannabinoids using terahertz spectroscopy. This method involves acquiring the absorption spectrum of the sample within a specific terahertz frequency band, extracting repeatable characteristic absorption peaks, and using information such as peak position, peak combination, and local peak shape distribution to achieve rapid screening and differentiation of target synthetic cannabinoids. Summary of the Invention

[0008] The technical problem this invention aims to solve is to provide a method for identifying synthetic cannabinoids using terahertz spectroscopy. This invention addresses the problems in existing rapid screening methods for new psychoactive substances, such as the rapid structural updates of synthetic cannabinoids, the difficulty in distinguishing analogs, and the relatively complex pretreatment and long detection cycle of conventional confirmation methods. The method proposes a terahertz spectroscopy-based method for identifying synthetic cannabinoids. This method acquires the terahertz absorption spectrum of the sample, extracts reproducible characteristic absorption peaks, and rapidly screens and identifies whether the sample is a target synthetic cannabinoid based on the peak position, peak combination, and local peak shape distribution.

[0009] For ease of description, in this invention, cyclohexylmethylindazole carboxamide refers to N-(1-carbamoyl-2-methylpropyl)-1-(cyclohexylmethyl)indazole-3-carboxamide; 4-fluorobenzylindazole carboxamide refers to N-(1-carbamoyl-2-methylpropyl)-1-(4-fluorobenzyl)indazole-3-carboxamide; and pentylindazole carboxamide refers to N-(1-carbamoyl-2-methylpropyl)-1-pentylindazole-3-carboxamide.

[0010] This invention provides a method for identifying synthetic cannabinoids using terahertz spectroscopy, comprising:

[0011] Test the sample and obtain its terahertz absorption spectrum, then extract the characteristic absorption peak parameters corresponding to the sample.

[0012] The characteristic absorption peak parameters of the extracted sample to be tested are compared with the preset standard characteristic absorption peaks of the target synthetic cannabinoids to determine whether the sample to be tested is the target synthetic cannabinoid. The characteristic absorption peak parameters include one or more of the following: peak position, peak position combination, number of characteristic peaks, and local peak shape distribution.

[0013] The determination of whether the sample to be tested is a target synthetic cannabinoid substance involves screening and differentiation.

[0014] The sample to be tested is one or more of the following: solid sample, powder sample, tablet sample, or suspected solid sample that may contain the target synthetic cannabinoid.

[0015] Furthermore, the sample to be tested is a solid powder sample or a tablet formed by pressing powder.

[0016] The method for testing the sample and obtaining its terahertz absorption spectrum, and then extracting the characteristic absorption peak parameters corresponding to the sample, includes the following steps:

[0017] (1) Mix the sample to be tested and the substrate material and compress them into a tablet to obtain the tablet sample to be tested;

[0018] (2) The sample chamber of the terahertz spectroscopy detection device is dried, the background signal is measured, and the substrate material is pressed into a pellet as the background;

[0019] (3) Place the sample to be tested on the sample holder of the terahertz spectroscopy detection device for testing, collect the terahertz spectrum of the sample, calculate and obtain its terahertz absorption spectrum;

[0020] (4) Preprocess the terahertz absorption spectrum and extract the characteristic absorption peak parameters.

[0021] In step (1), the sample to be tested is ground into powder.

[0022] In step (1), the substrate material is a solid material with a transmittance of more than 90% for terahertz frequencies and no interference absorption in the characteristic frequency band.

[0023] The substrate material includes one or more of potassium bromide and cyclic olefin copolymers.

[0024] In step (1), the mass ratio of the sample to be tested to the substrate material is (1~8):40.

[0025] The drying process in step (2) reduces the humidity in the sample room to below 3%.

[0026] In step (2), the substrate material pressing is a pure substrate material pressing with the same thickness as the pressing sample to be tested.

[0027] The calculation formula in step (3) is as follows: Where Ab represents the absorption data, Sam represents the frequency domain plot data, and Ref represents the reference frequency domain plot data.

[0028] Step (4) Preprocess the terahertz absorption spectrum and extract characteristic absorption peak parameters: Perform preprocessing of the terahertz absorption spectrum including baseline correction, extract the characteristic absorption peaks of the sample to be tested that are repeatable in the range of 6 ~ 20 THz, and record the peak position, peak position combination and local peak shape distribution.

[0029] The determination of whether the sample to be tested is a target synthetic cannabinoid involves the following steps: when the peak positions of multiple characteristic absorption peaks of the sample to be tested are within the allowable deviation range and match the peak positions of the characteristic absorption peaks of the preset synthetic cannabinoids, and the peak position combination, the number of characteristic peaks and / or the local peak shape distribution meet the preset matching conditions of the corresponding target synthetic cannabinoids, the sample to be tested is determined to be the corresponding target synthetic cannabinoid.

[0030] The deviation range is ±10%, which can be adjusted according to the instrument resolution, sample preparation conditions, substrate material, and actual testing conditions.

[0031] The determination is based on a combination of characteristic absorption peak parameters within multiple characteristic frequency bands, including at least one of 8.0 ~ 10.5 THz, 12.5 ~ 16.5 THz, and 16.5 ~ 20.0 THz.

[0032] The local peak shape distribution includes spectral features such as the single or multiple peak shapes of absorption peaks within the characteristic frequency band, shoulder peaks, distribution relationships of adjacent peaks, and the contours of local absorption bands. During the discrimination process, a single characteristic absorption peak is not used as the sole criterion; instead, a comprehensive judgment is made based on the peak positions, peak position combinations, number of characteristic peaks, and local peak shape distribution of multiple absorption peaks.

[0033] The target synthetic cannabinoids include, but are not limited to, at least one of N-(1-carbamoyl-2-methylpropyl)-1-(cyclohexylmethyl)indazole-3-carboxamide, N-(1-carbamoyl-2-methylpropyl)-1-(4-fluorobenzyl)indazole-3-carboxamide, and N-(1-carbamoyl-2-methylpropyl)-1-pentylindazole-3-carboxamide.

[0034] The pre-defined characteristic absorption peak positions and combinations thereof for the target synthetic cannabinoids include at least one of the following:

[0035] N-(1-carbamoyl-2-methylpropyl)-1-(cyclohexylmethyl)indazole-3-carboxamide has characteristic absorption peaks at 8.12, 9.36, 10.26, 12.95, 13.76 and 15.41 THz;

[0036] N-(1-carbamoyl-2-methylpropyl)-1-(4-fluorobenzyl)indazole-3-carboxamide has characteristic absorption peaks at 8.99, 10.20, 14.68, 15.55, 16.33 and 17.54 THz;

[0037] N-(1-carbamoyl-2-methylpropyl)-1-pentylindazole-3-carboxamide has characteristic absorption peaks at 8.67, 10.12, 13.06, 14.25, 15.67, 16.97 and 19.65 THz.

[0038] This method can be extended to determine the authenticity of other target substances.

[0039] This invention uses the sample to be tested as the detection object, acquiring its terahertz absorption spectrum; extracting characteristic absorption peak parameters, and comparing them with the terahertz characteristic peak information of preset synthetic cannabinoids; based on the matching of multiple characteristic parameters within the allowable deviation range, the target synthetic cannabinoid in the sample to be tested is rapidly screened and identified. The characteristic absorption peak parameters include information such as peak position, peak position combination, number of characteristic peaks, and local peak shape distribution. In this embodiment, the synthetic cannabinoids include cyclohexylmethylindazole formamide, 4-fluorobenzylindazole formamide, and pentylindazole formamide. These three have different terahertz absorption characteristics in the 6–20 THz range, specifically manifested in differences in characteristic peak position, number of peaks, peak position combination, and local peak shape distribution, which can form characteristic peak combination information for differentiation and identification. The allowable deviation range is approximately ±10%, which can be adjusted according to instrument resolution, sample preparation conditions, base materials, and actual testing conditions. By matching the terahertz spectral characteristics of the sample with preset characteristic peak information, it is possible to determine whether the sample belongs to synthetic cannabinoids and its specific type. This method requires small sample amounts, involves simple pretreatment, and is rapid, making it suitable for the rapid screening and preliminary identification of synthetic cannabinoids among new psychoactive substances.

[0040] Beneficial effects

[0041] This invention employs terahertz spectroscopy to screen and differentiate target synthetic cannabinoids in test samples. The entire process is simple and convenient, typically completed within a short time. Compared to traditional methods requiring complex pretreatment, chromatographic separation, or specialized confirmatory conditions, this invention shortens the detection process, improves preliminary screening efficiency, and helps address the current problem of insufficient differentiation efficiency for structurally similar synthetic cannabinoids in rapid screening scenarios. Furthermore, this invention requires only a small amount of sample powder, resulting in minimal sample loss, and can be used for rapid screening and preliminary identification of synthetic cannabinoids among new psychoactive substances. Attached Figure Description

[0042] Figure 1 To detect the terahertz absorption spectra of three target synthetic cannabinoids using the method of this invention, the test frequency range was 6 ~ 20 THz;

[0043] Figure 2 Locally magnified terahertz absorption spectra of three target synthetic cannabinoids in the 8.0–10.5 THz frequency band;

[0044] Figure 3 The magnified terahertz absorption spectra of three target synthetic cannabinoids in the 12.5–16.5 THz frequency band are shown.

[0045] Figure 4 Locally magnified terahertz absorption spectra of three target synthetic cannabinoids in the 16.5–20.0 THz frequency band. Detailed Implementation

[0046] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0047] Example 1

[0048] This invention provides a method for identifying synthetic cannabinoids using terahertz spectroscopy. The method acquires the terahertz absorption spectrum of the sample in the range of 6–20 THz, extracts the peak positions, peak combinations, and local peak shape distribution of characteristic absorption peaks, and compares this information with the terahertz characteristic peak information of a preset target synthetic cannabinoid. This enables rapid screening and differentiation of whether the sample belongs to the corresponding target synthetic cannabinoid.

[0049] In this embodiment, the target synthetic cannabinoids include cyclohexylmethylindazole formamide, 4-fluorobenzylindazole formamide, and pentylindazole formamide. Specifically, the steps include:

[0050] (1) Grind the sample to be tested into powder, then mix it with a substrate material that has high transmittance to terahertz waves and does not produce obvious interference absorption in the detection frequency band in a certain proportion, and then put it into a tablet press to press it to obtain the mixed tablet sample required for testing.

[0051] (2) The sample chamber of the terahertz spectroscopy detection device is dried to reduce the humidity in the sample chamber to below 3%, the background signal is measured, and the spectrum of the substrate material pellet prepared under the same conditions is collected as the background.

[0052] (3) Place the prepared mixed tablet sample on the sample holder for testing, obtain the terahertz spectrum of the sample in the frequency range of 6 ~ 20 THz, and calculate its terahertz absorption spectrum;

[0053] Calculation formula: ;

[0054] Where Ab represents the absorption data, Sam represents the frequency domain plot data, and Ref represents the reference frequency domain plot data;

[0055] (4) Perform baseline correction and other preprocessing on the terahertz absorption spectrum, extract the characteristic absorption peaks of the sample to be tested that are repeatable in the range of 6 ~ 20 THz, and record the peak position, peak position combination, number of characteristic peaks and local peak shape distribution.

[0056] (5) Compare the peak position, peak position combination, number of characteristic peaks and local peak shape distribution of the sample to be tested with the characteristic peak information of the preset target synthetic cannabinoids, and output the identification result of whether the sample to be tested belongs to the corresponding target synthetic cannabinoids within the allowable deviation range.

[0057] In a specific implementation:

[0058] Instruments: Terahertz spectroscopy detection device, electronic balance, grinding tools, tablet press, sample rack; Samples: Cyclohexylmethylindazole formamide, 4-fluorobenzylindazole formamide, pentylindazole formamide, cyclic olefin copolymer;

[0059] Preparation of synthetic cannabinoid samples:

[0060] (1) Weigh 2 mg of cyclohexylmethylindazole carboxamide, 2 mg of 4-fluorobenzylindazole carboxamide, and 2 mg of pentylindazole carboxamide sample powders using an electronic balance, and then grind and mix them thoroughly with 40 mg of cyclic olefin copolymer in a grinding apparatus. Then place the resulting mixed powders into tablets using a tablet press to obtain the mixed tablet samples required for testing. Separately, compress the cyclic olefin copolymer into tablets under the same conditions as a background reference.

[0061] (2) The sample chamber of the terahertz spectroscopy detection device is dried to reduce the humidity in the sample chamber to below 3%, the background signal is measured, and the spectrum of the cyclic olefin copolymer tablet is collected as the background.

[0062] (3) Place the prepared mixed tablet samples on the sample holder for testing, obtain the terahertz spectrum of each sample in the frequency range of 6 ~ 20 THz, and calculate its terahertz absorption spectrum; Calculation formula:

[0063] ;

[0064] Where Ab represents the absorption data, Sam represents the frequency domain plot data, and Ref represents the reference frequency domain plot data;

[0065] Combination Figures 1 to 4 The terahertz absorption spectrum obtained in this embodiment will be explained.

[0066] like Figure 1 Terahertz absorption spectra of three target synthetic cannabinoids in the range of 6–20 THz are shown to illustrate the overall absorption spectrum and characteristic peak distribution of the three substances. The three target synthetic cannabinoids are cyclohexylmethylindazole carboxamide, 4-fluorobenzylindazole carboxamide, and pentylindazole carboxamide. Figure 1 It can be seen that the three substances all exhibit multiple reproducible characteristic absorption peaks in the range of 6 to 20 THz, but their peak position distribution, number of peaks and local peak shapes are different, indicating that terahertz absorption spectroscopy can provide fingerprint identification information for the above-mentioned target synthetic cannabinoids.

[0067] like Figure 2The image shown is a magnified view of the 8.0–10.5 THz frequency band, illustrating the differences in characteristic peak positions for the three substances in the low-frequency region. Within this band, all three substances exhibit characteristic absorption responses, but their peak distributions differ: cyclohexylmethylindazole formamide shows characteristic absorption peaks at approximately 8.12, 9.36, and 10.26 THz; 4-fluorobenzylindazole formamide shows characteristic absorption peaks at approximately 8.99 and 10.20 THz; and pentylindazole formamide shows characteristic absorption peaks at approximately 8.67 and 10.12 THz. This frequency band can be used to compare the differences in the distribution of characteristic peaks in the low-frequency region for the three substances.

[0068] like Figure 3 The image shown is a magnified view of the 12.5–16.5 THz frequency band, illustrating the differences in peak position combinations among the three substances within the main characteristic peak concentration region. This frequency band represents a region where the peak position differences among the three substances are relatively concentrated. Cyclohexylmethylindazole formamide exhibits characteristic absorption peaks at approximately 12.95, 13.76, and 15.41 THz; 4-fluorobenzylindazole formamide exhibits characteristic absorption peaks at approximately 14.68, 15.55, and 16.33 THz; and pentylindazole formamide exhibits characteristic absorption peaks at approximately 13.06, 14.25, and 15.67 THz. The characteristic peaks of the three substances in this frequency band show a staggered distribution, which can serve as one of the main identification regions for distinguishing the three target synthetic cannabinoids.

[0069] like Figure 4 The image shown is a magnified view of the 16.5–20.0 THz frequency band, illustrating the differences in auxiliary identification peak positions and local peak shape distributions of the three substances in the higher frequency range. Within this band, the differences in high-frequency absorption characteristics of the different substances become more apparent. 4-Fluorobenzylindazole formamide exhibits a characteristic absorption peak at approximately 17.54 THz, while pentylindazole formamide shows characteristic absorption peaks at approximately 16.97 and 19.65 THz. The absorption peak near 19.65 THz, in particular, can serve as an important auxiliary identification feature for pentylindazole formamide. This frequency band can be combined with peak positions in the 8.0–10.5 THz and 12.5–16.5 THz bands for the differentiation and identification of target substances.

[0070] Depend on Figures 1 to 4 It is known that cyclohexylmethylindazole formamide, 4-fluorobenzylindazole formamide, and pentylindazole formamide all possess identifiable terahertz absorption characteristics in the 6–20 THz range, but they differ in characteristic peak position, number of characteristic peaks, peak combination, and local peak shape distribution. Therefore, it can be considered that… Figure 1 The overall absorption spectrum shown is Figures 2 to 4The local magnified frequency bands shown are used in combination as the basis for peak position matching between the sample to be tested and the preset target synthetic cannabinoids.

[0071] (4) Analyze the terahertz absorption spectrum data of the sample to be tested, extract the peak position, peak position combination, number of characteristic peaks and local peak shape distribution of its terahertz characteristic absorption peaks, and compare them with the terahertz characteristic peak information of the preset synthetic cannabinoid target substance. The peak position matching refers to the fact that multiple characteristic absorption peaks of the sample to be tested appear within the allowable deviation range near the characteristic peak of the preset target substance. The allowable deviation range is about ±10%, which can be adjusted according to the instrument resolution, sample preparation conditions, substrate material and actual test conditions. The local peak shape distribution includes the single peak or multiple peak morphology of the absorption peaks in the characteristic frequency band, peak shoulders, distribution relationship of adjacent peaks and local absorption band contours and other spectral features.

[0072] During the discrimination process, the peak positions and combinations of characteristic absorption peaks are the primary basis, while the number of characteristic peaks and the local peak shape distribution are secondary bases. A single characteristic absorption peak is not the sole criterion for judgment. When multiple absorption peaks of the sample match the peak position combinations in the preset characteristic peak library, and its local peak shape distribution is consistent with or substantially consistent with the corresponding target substance, the sample can be determined to be suspected to belong to the corresponding target synthetic cannabinoid. When only some characteristic peaks match but are insufficient to form a stable peak position combination, it can be determined to be a suspected sample or a sample to be confirmed. When its characteristic peak positions and peak position combinations do not match the preset target substance, it can be determined not to belong to the preset target synthetic cannabinoid.

[0073] In this embodiment, the preset synthetic cannabinoid target substances include cyclohexylmethylindazole formamide, 4-fluorobenzylindazole formamide, and pentylindazole formamide. Specifically, within the allowable error range: when the test sample detects a matching combination of characteristic absorption peaks at approximately 8.12, 9.36, 10.26, 12.95, 13.76, and 15.41 THz, it can be identified as cyclohexylmethylindazole formamide; when the test sample detects a matching combination of characteristic absorption peaks at approximately 8.99, 10.20, 14.68, 15.55, 16.33, and 17.54 THz, it can be identified as 4-fluorobenzylindazole formamide; and when the test sample detects a matching combination of characteristic absorption peaks at approximately 8.67, 10.12, 13.06, 14.25, 15.67, 16.97, and 19.65 THz, it can be identified as pentylindazole formamide.

[0074] (5) Based on the matching results of the peak position, peak position combination, number of characteristic peaks and local peak shape distribution of the above-mentioned multiple characteristic absorption peaks, output the identification results of whether the sample to be tested belongs to the preset target synthetic cannabinoids and its specific substance type.

[0075] The method of the present invention is applicable to solid samples, powder samples, tablet samples, and suspected solid samples that may contain target synthetic cannabinoids, including the original substance, powder, and samples that can be prepared into tablet form.

[0076] Synthetic cannabinoids have complex structures, and different analogs often differ in their parent nucleus, side chains, or substituents. This invention determines whether a sample belongs to a target synthetic cannabinoid by observing its terahertz absorption spectrum and comparing the peak positions, combinations of peak positions, and local peak shapes of characteristic absorption peaks with the characteristic peak information of a preset target synthetic cannabinoid. In this embodiment, cyclohexylmethylindazole formamide, 4-fluorobenzylindazole formamide, and pentylindazole formamide exhibit different characteristic peak combinations in the 6-20 THz range, enabling rapid differentiation of the three target substances. Existing detection methods have not yet correlated these terahertz characteristic peak combinations with the identification of the target synthetic cannabinoids, making it difficult to achieve the rapid screening and differentiation described in this invention. Therefore, this patent possesses certain innovativeness and uniqueness.

Claims

1. A method for identifying synthetic cannabinoids using terahertz spectroscopy, comprising: Test the sample and obtain its terahertz absorption spectrum, then extract the characteristic absorption peak parameters corresponding to the sample. The characteristic absorption peak parameters of the extracted sample to be tested are compared with the preset standard characteristic absorption peaks of the target synthetic cannabinoids to determine whether the sample to be tested is the target synthetic cannabinoid. The characteristic absorption peak parameters include one or more of the following: peak position, peak position combination, number of characteristic peaks, and local peak shape distribution.

2. The method according to claim 1, characterized in that, The sample to be tested is one or more of the following: solid sample, powder sample, and tablet sample.

3. The method according to claim 1, characterized in that, The method for testing the sample and obtaining its terahertz absorption spectrum, and then extracting the characteristic absorption peak parameters corresponding to the sample, includes the following steps: (1) Mix the sample to be tested and the substrate material and compress them into a tablet to obtain the tablet sample to be tested; (2) The sample chamber of the terahertz spectroscopy detection device is dried, the background signal is measured, and the substrate material is pressed into a pellet as the background; (3) Place the sample to be tested on the sample holder of the terahertz spectroscopy detection device for testing, collect the terahertz spectrum of the sample, calculate and obtain its terahertz absorption spectrum; (4) Preprocess the terahertz absorption spectrum and extract the characteristic absorption peak parameters.

4. The method according to claim 3, characterized in that, In step (1), the substrate material is a solid material with a terahertz transmittance of over 90% and which does not cause interference absorption in the characteristic frequency band.

5. The method according to claim 4, characterized in that, The substrate material includes one or more of potassium bromide and cyclic olefin copolymers.

6. The method according to claim 3, characterized in that, The drying process in step (2) reduces the humidity in the sample room to below 3%.

7. The method according to claim 1, characterized in that, The determination of whether the sample to be tested is a target synthetic cannabinoid is as follows: when the peak positions of multiple characteristic absorption peaks of the sample to be tested are within the allowable deviation range and match the peak positions of the characteristic absorption peaks of the preset synthetic cannabinoid, and the peak position combination, the number of characteristic peaks and / or the local peak shape distribution meet the preset matching conditions of the corresponding target synthetic cannabinoid, the sample to be tested is determined to be the corresponding target synthetic cannabinoid. The deviation range is ±10%.

8. The method according to claim 1, characterized in that, The determination is based on a combination of characteristic absorption peak parameters within multiple characteristic frequency bands, including at least one of 8.0 ~ 10.5 THz, 12.5 ~ 16.5 THz, and 16.5 ~ 20.0 THz.

9. The method according to claim 1, characterized in that, The pre-defined characteristic absorption peak positions and combinations thereof for the target synthetic cannabinoids include at least one of the following: N-(1-carbamoyl-2-methylpropyl)-1-(cyclohexylmethyl)indazole-3-carboxamide has characteristic absorption peaks at 8.12, 9.36, 10.26, 12.95, 13.76 and 15.41 THz; N-(1-carbamoyl-2-methylpropyl)-1-(4-fluorobenzyl)indazole-3-carboxamide has characteristic absorption peaks at 8.99, 10.20, 14.68, 15.55, 16.33 and 17.54 THz; N-(1-carbamoyl-2-methylpropyl)-1-pentylindazole-3-carboxamide has characteristic absorption peaks at 8.67, 10.12, 13.06, 14.25, 15.67, 16.97 and 19.65 THz.

10. The method according to claim 1, characterized in that, This method can be extended to determine the authenticity of other target substances.

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