Department of Pharmacal Sciences, Harrison School of Pharmacy, Auburn University, Auburn, AL 36849, USA.
Forensic Sci Int. 2013 Sep 10;231(1-3):54-60. doi: 10.1016/j.forsciint.2013.04.024. Epub 2013 May 11.
The dimethoxybenzoylpiperazines show mass spectra characteristic for this set of six regioisomeric substances and the position of ring substitution for the dimethoxy groups can be determined by vapor phase infrared methods. The dimethoxybenzoylpiperazines are characterized by several fragment ions unique to the mass spectra for this set of regioisomeric compounds. Ions at m/z 165 and 182 indicate the presence of the dimethoxybenzoyl and dimethoxybenzamide groups while low mass ions at m/z 56, 69 and 85 are characteristic of the piperazine ring in these isomeric compounds. The mass spectra for these regioisomeric dimethoxybenzoylpiperazines are almost identical and this method alone does not provide for the confirmation of identity of any one of the isomers to the exclusion of the other compounds. The perfluoroacyl derivatives of the six regioisomers were resolved by gas chromatography and their mass spectra showed some differences in relative abundance of fragment ions without the appearance of any unique fragments for specific confirmation of structure. Gas chromatography with infrared detection (GC-IRD) provides direct confirmatory data for the differentiation between the regioisomeric underivatized dimethoxybenzoylpiperazines.
二甲氧基苯甲酰基哌嗪呈现出这一组六个位置异构体物质的特征质谱，并且可以通过气相红外方法确定二甲氧基的环取代位置。二甲氧基苯甲酰基哌嗪的特征是具有一组位置异构体化合物的质谱中特有的几个碎片离子。质荷比为 165 和 182 的离子表明存在二甲氧基苯甲酰基和二甲氧基苯甲酰胺基团，而质荷比为 56、69 和 85 的低质量离子则是这些异构体化合物中哌嗪环的特征。这些位置异构体二甲氧基苯甲酰基哌嗪的质谱几乎相同，仅这种方法不能排除其他化合物，确认任何一个异构体的同一性。六种位置异构体的全氟酰基衍生物通过气相色谱法得到分离，它们的质谱显示碎片离子的相对丰度存在一些差异，而没有出现任何特定结构确认的独特碎片。带有红外检测的气相色谱法（GC-IRD）为区分未经衍生的二甲氧基苯甲酰基哌嗪的位置异构体提供了直接的确认数据。
