CN-121994963-A - Method for detecting tertiary amine type nizine substances

CN121994963ACN 121994963 ACN121994963 ACN 121994963ACN-121994963-A

Abstract

The invention relates to a detection method of tertiary amine type nizine substances. Aiming at the problem that in the analysis of the tertiary amine type Nizine substance in electrospray ion source mass spectrum, the part with structural difference is lost by neutral fragments, the mass spectrum data of the tertiary amine type Nizine substance is basically the same, and the qualitative analysis of structural identification can not be carried out through the mass spectrum data. The invention provides a method for converting tertiary amine type Nizine substances into corresponding N-oxides by an oxidation pretreatment method, and the method changes the protonation position of the tertiary amine type Nizine substances in an electrospray ion source, so that fragments with positrons can be generated on the part with functional group difference in the structure, the functional group characteristics in the structure are reflected, and the purpose of structure identification and qualitative analysis by mass spectrum characteristic fragment data is realized. The method is simple and convenient to operate, is suitable for mass spectrum of a conventional electrospray ionization source and a neutral gas collision cell, and can provide effective technical means for reliable identification and judicial identification of the substances.

Inventors

LUO XUAN
LUO QIULIAN
ZHU DECHAO
HUANG KEJIAN
YANG NING
LIU XIAOFENG
LIAO XUEQING
LI CHENGHU
LIANG SHUTING
HU MINGFENG

Assignees

广西大学
广西壮族自治区公安厅禁毒情报技术中心

Dates

Publication Date: 20260508
Application Date: 20260225

Claims (7)

1. The method for detecting the tertiary amine type nique substances is characterized by comprising the following steps of: (1) Oxidizing the tertiary amine type nixie substances by hydrogen peroxide to obtain N-oxides of the tertiary amine type nixie substances; (2) Respectively carrying out LC-MS detection on N-oxide of tertiary amine type nizine substances and tertiary amine type nizine substances; (3) And analyzing the specific structure of the tertiary amine type Nizine substances according to the LC-MS detection result.
2. The method for detecting a tertiary amine type Nizine substance as claimed in claim 1, wherein in the step (1), (S1) dissolving a tertiary amine type nixie substance sample in acetonitrile as a reaction substrate, wherein the concentration of an acetonitrile solution of the tertiary amine type nixie substance sample is 0.5-5 mg/mL; (S2) adding the acetonitrile solution of the tertiary amine type nique substance sample obtained in the step (S1) into hydrogen peroxide with the mass fraction of less than or equal to 50% and exceeding 3-5%, and shaking uniformly; and (S3) placing the reaction system obtained in the step (S2) in a water bath kettle with the temperature of 40-80 ℃ for uniform vibration reaction to obtain the N-oxide of the tertiary amine type Nizine substance.
3. The method for detecting tertiary amine type nique according to claim 1, wherein in the step (2), the N-oxide of tertiary amine type nique is added into a mobile phase mixed solution to obtain the N-oxide of tertiary amine type nique with the concentration of 0.5-5 mug/mL, the mobile phase mixed solution is a mixed solution of MPA and MPB, the volume ratio of mpa=1:9 in the mobile phase mixed solution, the MPA is 10mM ammonium acetate aqueous solution containing 0.1% formic acid by volume fraction, and the MPB is acetonitrile containing 0.1% formic acid by volume fraction.
4. The method for detecting a tertiary amine-type Nizine compound according to claim 1, wherein in the step (2), when the N-oxide of the tertiary amine-type Nizine compound is subjected to LC-MS detection, The liquid phase condition is that the temperature of a column oven is set to be 30-50 ℃, the sample injection amount is 0.5-5 mu L, MPA and MPB are used for eluting, the total flow rate of a mobile phase is 0.1-0.4 mL/min, and the gradient elution procedure is as follows: MPB with 10% of 0-0.1 min, A linear gradient of 10-40% MPB for 0.1-20 min, A linear gradient of 40% -95% MPB for 20-22 min, 22-28 Min is 95% MPB, A linear gradient of 95-10% MPB for 28-28.1 min, The mobile phase was stopped at 38 min at 10% MPB equilibrium with a total run time of 38 min; The MPA is 10 mM ammonium acetate aqueous solution containing 0.1% formic acid by volume fraction, The MPB is acetonitrile containing 0.1% formic acid by volume fraction. The mass spectrum conditions comprise electrospray positive ion mode, atomizing gas N 2 flow rate of 1-10L/min, drying gas N 2 pressure of 0.1 Mpa, argon as collision gas, CDL temperature of 200 ℃, heating block temperature of 200 ℃, interface voltage of 4.5 KV, detector voltage of 1.63 KV, collision energy of 20-40%, accumulated time of 50 ms and separation width of 3 Da.
5. The method for detecting a tertiary amine type Nizine compound according to claim 1, wherein in the step (2), when the tertiary amine type Nizine compound is subjected to LC-MS detection, The liquid phase condition is that the temperature of a column oven is set to be 30-50 ℃, sample injection is carried out for 0.5-5 mu L, MPA and MPB are used for eluting, the total flow rate of a mobile phase is 0.1-0.4 mL/min, 90% MPB is used for isocratic eluting for 3-10 minutes, The MPA is 10 mM ammonium acetate aqueous solution containing 0.1% formic acid by volume fraction, The MPB is acetonitrile containing 0.1% formic acid by volume fraction. The mass spectrum conditions comprise electrospray positive ion mode, atomizing gas N 2 flow rate of 1-10L/min, drying gas N 2 pressure of 0.1 Mpa, argon as collision gas, CDL temperature of 200 ℃, heating block temperature of 200 ℃, interface voltage of 4.5 KV, detector voltage of 1.63 KV, collision energy of 20-50%, accumulated time of 50 ms and separation width of 3 Da.
6. The method for detecting tertiary amine type Nizine compound according to claim 1, wherein in the step (3), the structure of R 1 and R 4 is determined by comparing the mass-to-charge ratio of the characteristic fragment ion peak F1 with the mass-to-charge ratio of the N-oxide of tertiary amine type Nizine compound in the table 1 based on the primary mass spectrum data of the N-oxide of tertiary amine type Nizine compound detected by LC-MS, when R 1 is determined to be-NH 2 or-NO 2 , R 1 is determined by calculating the difference between the N-oxide of tertiary amine type Nizine compound and the molecular ion peak of tertiary amine type Nizine compound, when the difference is 16 Da is nitro, and when the difference is 46 Da is amino, the structure of R 1 and R 4 is checked by comparing the mass-to-charge ratio of the N-oxide molecular ion peak M1 of tertiary amine type Nizine compound in the table 2 and the structure of R 2 and R 3 is determined, TABLE 1 comparison of the mass to charge ratios of the characteristic fragment ion peaks F1 with the specific Structure of R 1 and R 4 TABLE 2 Mass to charge ratio comparison Table for ion peak M1 of N-oxide molecules In Table 2, R 2 and R 3 are each-C 2 H 5 , in each case R 2 and R 3 are linked, i.e. - (CH 2 ) 4 -and are closed with the N atom in position 12 to form a tetrahydropyrrole ring, When the correspondence between the mass spectrum data and the table 1 and the table 2 is not the same, other structures are adopted, When one mass-to-charge ratio corresponds to two possible structures, the distinction is made by nuclear magnetic resonance techniques.
7. The preparation method of the N-oxide of the tertiary amine type nique substance is characterized by comprising the following steps: (step 1) dissolving a tertiary amine type nixie substance sample in acetonitrile as a reaction substrate, wherein the concentration of an acetonitrile solution of the tertiary amine type nixie substance sample is 0.5-5 mg/mL; (step 2) adding the acetonitrile solution of the tertiary amine type nizine substance sample obtained in the step (step 1) into hydrogen peroxide with the mass fraction of less than or equal to 50% and exceeding 3-5%, and shaking uniformly; (step 3) placing the reaction system obtained in the step2 into a water bath kettle at 40-80 ℃ to perform uniform-speed oscillation reaction to obtain the N-oxide of the tertiary amine type Nizine substance.

Description

Method for detecting tertiary amine type nizine substances Technical Field The invention relates to a detection method of tertiary amine type nizine substances, and belongs to the technical field of analysis and detection. Background The nigeline substance refers to a substance with a chemical structure which is in accordance with one or more of the following conditions compared with etodolac (2- [2- (4-ethoxybenzyl) -5-nitro-1H-benzimidazol-1-yl ] -N, N-diethyl-1-ethylamine), wherein (1) substituted or unsubstituted 1H-benzimidazolyl is used for replacing 5-nitro-1H-benzimidazolyl, (second) substituted or unsubstituted C1-C2 alkyl is used for replacing methylene between 1H-benzimidazolyl and phenyl, (third) substituted or unsubstituted aromatic group is used for replacing 4-ethoxyphenyl, and (fourth) substituted or unsubstituted amino is used for replacing N, N-diethylamino. The compounds are mu opioid receptor agonists with high affinity and high efficacy. At the same dosage, the nique substance can induce respiratory depression which is more serious and lasting than fentanyl. LC-MS has been widely used in place under arrest drug and toxicology analysis, and the combination of chromatography and high-resolution mass spectrometer can realize the characterization of unknowns and structural analogues, playing a key role in the identification and structural identification of new psychoactive substances. However, the new psychoactive materials of the nique class show highly consistent cleavage behavior in conventional LC-MS analysis, and it is difficult to generate ion fragments with structural discrimination value. Taking the nixie substances with side chains of triethylamine as an example, the substances often generate base peak fragments related to the side chains of the triethylamine and benzyl fragments with extremely low abundance, and if an ion trap mass spectrometer is adopted, the obtained fragment information is less because of one third effect, and the deficient information is difficult to realize the structural identification qualitative analysis of the tertiary amine nixie substances. Among the nique substances found at present, tertiary amine type accounts for a large proportion. Although the structural identification of the tertiary amine type nique substance can be realized by nuclear magnetic resonance technology, the instrument is expensive and needs professional staff to analyze the spectrogram. However, the mass spectrometry technology is still in a development stage, and the related equipment cost is high, so that the method is difficult to adapt to the requirements of judicial identification practice on technical popularity and economy. Disclosure of Invention The invention provides a detection method of tertiary amine type Nizine substances, aiming at the problem that in LC-MS detection of tertiary amine type Nizine substances, 2-benzyl benzimidazole parts are lost in neutral fragments, mass spectrum data are basically the same, and qualitative analysis of structure identification cannot be carried out through the mass spectrum data. In order to achieve the above purpose, the present invention adopts the following technical scheme: A method for detecting tertiary amine type nique substances comprises the following steps: (1) Oxidizing the tertiary amine type nixie substances by hydrogen peroxide to obtain N-oxides of the tertiary amine type nixie substances; (2) Respectively carrying out LC-MS detection on N-oxide of tertiary amine type nizine substances and tertiary amine type nizine substances; (3) And analyzing the specific structure of the tertiary amine type Nizine substances according to the LC-MS detection result. In the method for detecting the tertiary amine type nique substance, in the step (1), (S1) dissolving a tertiary amine type nixie substance sample in acetonitrile as a reaction substrate, wherein the concentration of an acetonitrile solution of the tertiary amine type nixie substance sample is 0.5-5 mg/mL; (S2) adding the acetonitrile solution of the tertiary amine type nique substance sample obtained in the step (S1) into hydrogen peroxide with the mass fraction of less than or equal to 50% and exceeding 3-5%, and shaking uniformly; and (S3) placing the reaction system obtained in the step (S2) in a water bath kettle with the temperature of 40-80 ℃ for uniform vibration reaction to obtain the N-oxide of the tertiary amine type Nizine substance. In the detection method of the tertiary amine type nique substances, in the step (2), N-oxide of the tertiary amine type nique substances is added into a mobile phase mixed solution to obtain N-oxide of the tertiary amine type nique substances with the concentration of 0.5-5 mug/mL for LC-MS detection, wherein the mobile phase mixed solution is a mixed solution of MPA and MPB, the volume ratio of MPA=1:9 in the mobile phase mixed solution, the MPA is 10 mM ammonium acetate aqueous solution containing 0.1% formic acid in volume fr