Objectives: To identify 1-(4-fluorophenyl)-2-(1-pyrrolidinyl) pentan-1-one (4-F-α-PVP) analog 1-(4-fluoro-3-methyl phenyl)-2-(1-pyrrolidinyl) pentan-1-one (4-F-3-Methyl-α-PVP) hydrochloride without reference substance.
Methods: The direct-injection electron ionization-mass spectrometry (EI-MS), GC-MS, electrospray ionization-high resolution mass spectrometry (ESI-HRMS), ultra-high performance liquid chromatography-high resolution tandem mass spectrometry (UPLC-HRMS/MS), nuclear magnetic resonance (NMR), ion chromatography and Fourier transform infrared spectroscopy (FTIR) were integrated utilized to achieve the structural analysis and characterization of the unknown compound in the sample, and the cleavage mechanism of the fragment ions was deduced by EI-MS and UPLC-HRMS/MS.
Results: By analyzing the direct-injection EI-MS, GC-MS, ESI-HRMS and UPLC-HRMS/MS of the compound in the samples, it was concluded that the unknown compound was a structural analog of 4-F-α-PVP, possibly with one more methyl group in the benzene ring. According to the analysis results of 1H-NMR and 13C-NMR, it was further proved that the methyl group is located at the 3-position of the benzene ring. Since the actual number of hydrogen in 1H-NMR analysis was one more than 4-F-3-Methyl-α-PVP neutral molecule, it was inferred that the compound existed in the form of salt. Ion chromatography analysis results showed that the compound contained chlorine anion (content 11.14%-11.16%), with the structural analysis of main functional group information by FTIR, the unknown compound was finally determined to be 4-F-3-Methyl-α-PVP hydrochloride.
Conclusions: A comprehensive method using EI-MS, GC-MS, ESI-HRMS, UPLC-HRMS/MS, NMR, ion chromatography and FTIR to identify 4-F-3-Methyl-α-PVP hydrochloride in samples is established, which will be helpful for the forensic science laboratory to identify this compound or other analog compounds.
目的: 研究在没有对照品的情况下鉴定检材中1-（4-氟苯基）-2-（N-吡咯烷基）-1-戊酮［1-（4-fluorophenyl）-2-（1-pyrrolidinyl） pentan-1-one，4-F-α-PVP］类似物1-（4-氟-3甲基苯基）-2-（N-吡咯烷基）-1-戊酮［1-（4-fluoro-3-methyl phenyl）-2-（1-pyrrolidinyl） pentan-1-one，4-F-3-Methyl-α-PVP］盐酸盐的方法。方法: 综合利用直接进样电子电离-质谱（electron ionization-mass spectrometry，EI-MS）、GC-MS、电喷雾离子化-高分辨质谱（electrospray ionization-high resolution mass spectrometry，ESI-HRMS）、超高效液相色谱-高分辨串联质谱（ultra-high performance liquid chromatography-high resolution tandem mass spectrometry，UPLC-HRMS/MS）、核磁共振（nuclear magnetic resonance，NMR）、离子色谱和傅里叶变换红外光谱法（Fourier transform infrared spectroscopy，FTIR），实现对检材中未知化合物的结构解析与表征，并对该化合物在EI-MS和UPLC-HRMS/MS两种质谱分析方式下生成碎片离子的裂解机制进行推导。结果: 通过对检材中化合物的直接进样EI-MS、GC-MS、ESI-HRMS和UPLC-HRMS/MS分析，推断出未知化合物为4-F-α-PVP的结构类似物，可能苯环中多了1个甲基。根据核磁共振氢谱（1H-nuclear magnetic resonance，1H-NMR）、核磁共振碳谱（13C-nuclear magnetic resonance，13C-NMR）等分析结果，进一步证明了甲基的位置在苯环的3-位。由于1H-NMR分析中实际氢的个数比4-F-3-Methyl-α-PVP中性分子多1个，推断该化合物以盐形式存在。离子色谱法分析结果表明该化合物含氯离子（含量11.14%~11.16%），结合FTIR对主要官能团信息的结构分析，最终确定该未知化合物为4-F-3-Methyl-α-PVP盐酸盐。结论: 建立了综合利用EI-MS、GC-MS、ESI-HRMS、UPLC-HRMS/MS、NMR、离子色谱和FTIR鉴定检材中4-F-3-Methyl-α- PVP盐酸盐的方法，将有助于法庭科学实验室在案件中鉴定该物质或其他具有类似结构的化合物。.
Keywords: 4-F-3-Methyl-α-PVP hydrochloride; forensic medicine; high resolution mass spectrometry; new psychoactive substance; nuclear magnetic resonance; structural analysis; toxicological analysis.