阅读说明：本技术 一种区分甲基***与n-异丙基苄胺的方法 (Method for distinguishing methamphetamine from N-isopropylamine ) 是由 罗奇志 戴开金 马安德 罗阳旭 杜娟 于 2019-10-18 设计创作，主要内容包括：本发明公开了一种区分甲基苯丙胺与N-异丙基苄胺的方法,该方法特异性强、分离度高、精密度、稳定性、重现性好,回收率高、结果准确,可同时对这两种化合物进行定性定量分析,在涉及冰毒定性定量的实际案例分析中,能有效区分甲基苯丙胺及其同分异构体N-异丙基苄胺,对于案件性质的判定和量刑具有重要意义。(The invention discloses a method for distinguishing methamphetamine from N-isopropylamine, which has the advantages of strong specificity, high separation degree, high precision, stability, good reproducibility, high recovery rate and accurate result, can simultaneously carry out qualitative and quantitative analysis on the two compounds, can effectively distinguish the methamphetamine and the isomer N-isopropylamine thereof in the actual case analysis related to the qualitative and quantitative analysis of ice toxicity, and has important significance for judging and controlling case properties.)

1. A method for distinguishing methamphetamine from N-isopropylamine, comprising the steps of:

1) preparing a test sample solution;

2) injecting the sample solution into a high performance liquid chromatography tandem mass spectrometer for determination, selecting characteristic ion pairs and characteristic fragment ions, comparing the retention time of chromatographic peaks of the sample solution and a standard sample, determining the nature of the characteristic ion pairs, the abundance ratio of the characteristic ion pairs and the characteristic ion fragments, and quantifying by using a peak area external standard method;

wherein, the liquid phase chromatographic conditions are as follows:

the chromatographic column adopts octadecylsilane chemically bonded silica or octaalkylsilane chemically bonded silica as a filler;

the mobile phase consists of a mobile phase A and a mobile phase B;

adopting ammonium acetate aqueous solution containing formic acid or ammonium formate aqueous solution containing formic acid as the mobile phase A;

acetonitrile or methanol is adopted as the mobile phase B;

the elution mode is isocratic elution or gradient elution.

2. The method of claim 1, wherein: the particle size of the filler is 1.7-5 μm.

3. The method of claim 2, wherein: the filler particle size was 1.7 μm.

4. The method of claim 1, wherein: and the mobile phase A adopts 5-20 mmol/L ammonium acetate aqueous solution containing 0.1% formic acid or 5-20 mmol/L ammonium formate aqueous solution containing 0.1% formic acid.

5. The method of claim 1, wherein: the elution mode is isocratic elution, and the volume ratio of the mobile phase A to the mobile phase B is 20/80 or 30/70.

6. The method of claim 5, wherein: the flow rate is 0.2-0.6 mL/min, and the column temperature is 30-45 ℃.

7. The method of claim 1, wherein: the mass spectrum detection adopts the following mass spectrum conditions:

electrospray positive ion mode (ESI +);

the detection mode is as follows: multiple reaction monitoring mode detection (MRM);

characteristic ion pair: the methamphetamine takes two pairs of ions with m/z150.1>119.1, m/z150.1>91.1 as characteristic ion pairs, and the N-isopropylbenzylamine takes two pairs of ions with m/z150.1>91.1, 150.1>58.1 as characteristic ion pairs;

characteristic ion fragment: characteristic fragment ions of methamphetamine are 119.1, 91.1 and 58.1, and characteristic fragment ions of N-isopropylbenzylamine are 91.1 and 58.1;

air curtain gas (CurtainGas, CUR)15 Psi; collisional gas (CollisionGas) Medium; spray voltage (ion spray voltage, IS) 5500V; temperature of atomization (TEM) 600 ℃; atomizing gas (IonSourceGas1)55 Psi; auxiliary gas (IonSourceGas2)65 Psi;

MRM mode ion pair parameters:

。

8. the method of claim 1, wherein: the preparation method of the sample solution comprises the following steps: taking a sample to be tested, ultrasonically dissolving the sample by using methanol as a solvent, and filtering the sample to obtain the product.

Technical Field

The invention relates to a method for distinguishing methamphetamine from N-isopropylamine, in particular to a high performance liquid chromatography-tandem mass spectrometry analysis method of the methamphetamine and the N-isopropylamine.

Background

Methamphetamine (MA), a first class of psychotropic drugs strictly regulated by China, has a central nervous excitation effect and strong addiction, and has a molecular formula of C₁₀H₁₅N, molecular weight of 149.23, colorless oily liquid at room temperature, white crystal or white powder of hydrochloride, and large block in appearance when purity is not highThe crystal form is similar to the form of ice, so it is commonly called "ice poison", which is the most commonly found variety in drug crime at present. N-isopropyl benzylamine (N-Isopropylbenzylamine, N-IBA) is an isomer of methamphetamine and has the following structural formula:

the compound is colorless or light yellow transparent liquid at normal temperature, has physical properties very close to those of methamphetamine, is organic base and organic synthesis raw materials commonly used in industry, and is mainly used for organic intermediates, antirust agents or drug precursors. The hydrochloride of the two is very similar in appearance, so the hydrochloride of the N-isopropyl benzylamine is often used for adulteration of the ice poison in recent years, which is commonly called as the pseudo ice poison or a diluent. No study at present finds that the N-isopropylamine has excitation function and no addiction, so that the N-isopropylamine does not belong to national regulation varieties. According to the crime law of the people's republic of China and the explanation of the highest people's law institute on the application of law to the case of drug administration (carried out from the beginning of 2016.4.11), in the case of drug administration, the quantity of drugs is directly related to the law of drug administration, and one of methamphetamine and N-isopropylaniline is a controlled drug and the other is an unregulated chemical raw material, but the controlled drug and the unregulated chemical raw material are easily mixed up during detection to cause false positive and increase the content of samples, so that the two are clearly distinguished and quantitatively analyzed, and the method has important significance for judging the property of the case and measuring the law.

From the current research, methods such as infrared spectroscopy technology, ice toxicity detection test paper and the like are difficult to distinguish methamphetamine from N-isopropylamine; the gas chromatography-mass spectrometry can effectively distinguish the two at higher concentration, but when the sample matrix is complex, more interference exists, so that the two are difficult to distinguish, and in addition, the identification is difficult at low concentration; the high performance liquid chromatography can effectively separate the methamphetamine and the N-isopropylamine, but the qualitative capability of the high performance liquid chromatography is not strong, so that the high performance liquid chromatography is used as an evidence map in court science and is deficient; the high performance liquid chromatography tandem mass spectrometry is a qualitative and quantitative analysis means accepted by court science, and reports of separating and analyzing methamphetamine and N-isopropylaniline by adopting the method are rare.

Disclosure of Invention

The invention aims to provide a high performance liquid chromatography tandem mass spectrometry analysis method for methamphetamine and N-isopropylamine, which can perform qualitative and quantitative analysis on the methamphetamine and the N-isopropylamine simultaneously.

The technical scheme adopted by the invention is as follows:

a method of distinguishing methamphetamine from N-isopropylamine, the method comprising the steps of:

1) preparing a test sample solution;

2) injecting the sample solution into a high performance liquid chromatography tandem mass spectrometer for determination, selecting characteristic ion pairs and characteristic fragment ions, comparing the retention time of chromatographic peaks of the sample solution and a standard sample, determining the nature of the characteristic ion pairs, the abundance ratio of the characteristic ion pairs and the characteristic ion fragments, and quantifying by using a peak area external standard method;

wherein, the liquid phase chromatographic conditions are as follows:

the chromatographic column adopts octadecylsilane chemically bonded silica or octaalkylsilane chemically bonded silica as a filler;

the mobile phase consists of a mobile phase A and a mobile phase B;

adopting ammonium acetate aqueous solution containing formic acid or ammonium formate aqueous solution containing formic acid as the mobile phase A;

acetonitrile or methanol is adopted as the mobile phase B;

the elution mode is isocratic elution or gradient elution.

Furthermore, the particle size of the filler is 1.7-5 μm.

Further, the filler particle size was 1.7 μm.

Further, the mobile phase A adopts 5-20 mmol/L ammonium acetate aqueous solution containing 0.1% formic acid or 5-20 mmol/L ammonium formate aqueous solution containing 0.1% formic acid.

Further, the elution mode is isocratic elution, and the volume ratio of the mobile phase A to the mobile phase B is 20/80 or 30/70.

Further, the flow rate is 0.2-0.6 mL/min, and the column temperature is 30-45 ℃.

Further, the mass spectrum detection adopts mass spectrum conditions as follows:

electrospray positive ion mode (ESI +);

the detection mode is as follows: multiple reaction monitoring mode detection (MRM);

characteristic ion pair: the methamphetamine takes two pairs of ions with m/z150.1>119.1 and m/z150.1>91.1 as characteristic ion pairs,

the N-isopropylbenzylamine takes two pairs of ions with m/z of 150.1>91.1 and 150.1>58.1 as characteristic ion pairs;

characteristic ion fragment: characteristic fragment ions of methamphetamine are 119.1, 91.1 and 58.1, and characteristic fragment ions of N-isopropylbenzylamine are 91.1 and 58.1;

air curtain gas (CurtainGas, CUR)15 Psi; collisional gas (CollisionGas) Medium; spray voltage (ion spray voltage, IS) 5500V; temperature of atomization (TEM) 600 ℃; atomizing gas (IonSourceGas1)55 Psi; auxiliary gas (IonSourceGas2)65 Psi;

MRM mode ion pair parameters:

。

further, the preparation method of the sample solution comprises the following steps: taking a sample to be tested, ultrasonically dissolving the sample by using methanol as a solvent, and filtering the sample to obtain the product.

The invention has the beneficial effects that:

the invention provides a method for distinguishing methamphetamine from N-isopropylamine, which has the advantages of strong specificity, high separation degree, high precision, stability, good reproducibility, high recovery rate and accurate result, can simultaneously carry out qualitative and quantitative analysis on the two compounds, can effectively distinguish the methamphetamine and the isomer N-isopropylamine thereof in the actual case analysis related to the qualitative and quantitative analysis of the ice toxicity, and has important significance for judging and controlling case properties.

Drawings

FIG. 1 is a HPLC-MS/MS separation chart of N-isopropylamine and methamphetamine;

FIG. 2 is an analytic graph of the structure of N-isopropylaniline (A. primary mass spectrum, B. secondary mass spectrum);

fig. 3 is an analytic graph of methamphetamine structure (a. primary mass spectrum, b. secondary mass spectrum).

Detailed Description

The invention provides a high performance liquid chromatography tandem mass spectrometry analysis method of methamphetamine and N-isopropylamine.

The inventors searched for separation and analysis using a PFP column, a C8 column, a C18 column, and the like. The PFP column is a chromatographic column commonly used for analyzing toxic drugs at present, but the retention time of the methamphetamine and the N-isopropylamine in the PFP column is consistent, the methamphetamine and the N-isopropylamine cannot be effectively separated, and the methamphetamine and the N-isopropylamine have common ion pairs with m/z150.1 being more than 91.1 and m/z150.1 being more than 57.3, so that the methamphetamine and the N-isopropylamine cannot be distinguished when subjected to liquid chromatography-mass spectrometry, and the misjudgment is very easy; during the test, the C8 column and the C18 column are found to be capable of effectively separating the two, but the separation effect of the C18 column is better.

The results of comparison with C18 columns filled with fillers having particle sizes of 5 μm, 3.5 μm,2.7 μm and 1.7 μm demonstrate that the separation effect and detection sensitivity are better when chromatographic columns filled with fillers having particle sizes of 1.7 μm and 2.7 μm are used.

The mobile phase optimizes systems such as methanol/water, acetonitrile/water, methanol/buffer solution, acetonitrile/buffer solution and the like, wherein the buffer solution system tests ammonium formate-formic acid and ammonium acetate-formic acid systems, the concentrations are respectively 5mmol/L, 10mmol/L and 20mmol/L, and finally, the ammonium acetate aqueous solution/acetonitrile system with 20mmol/L and the volume ratio of 20/80 isocratic elution or gradient elution is determined to be adopted, so that the optimal separation effect and detection sensitivity are realized.

The present invention will be described in further detail with reference to examples. It will also be understood that the following examples are included merely for purposes of further illustrating the invention and are not to be construed as limiting the scope of the invention, as the invention extends to insubstantial modifications and adaptations of the invention following in the light of the principles set forth herein. The specific process parameters and the like of the following examples are also only one example of suitable ranges, and the skilled person can make a selection within the suitable ranges through the description herein, and are not limited to the specific data of the following examples.