Nasiri Azadeh, Mokhtari Shaya, Jahani Reza, Daraie Bahram, Yazdanpanah Hassan, Faizi Mehrdad, Kobarfard Farzad
Department of Pharmacology and Toxicology, School of Pharmacy, Shahid Beheshti University of Medical Sciences Tehran Iran.
Food Safety Research Center, Shahid Beheshti University of Medical Sciences Tehran Iran.
RSC Adv. 2022 Jun 9;12(27):17096-17103. doi: 10.1039/d2ra00205a. eCollection 2022 Jun 7.
Liquid chromatography-tandem mass spectroscopy (LC-MS/MS) is an accurate and specific technique for drug residue analysis in different matrices. The high specificity and sensitivity of the multiple reaction monitoring (MRM) approach for detecting drugs such as aldehydes, which have the potential to change mass during the sample preparation phase, becomes a drawback during the analysis process. In this study, concerns about the intrusion of solvent molecules into spiramycin's chemical structure as an aldehydic drug as well as the stability of spiramycin in the milk matrix were addressed. Furthermore, the binding sites where the solvent molecules could bind to spiramycin molecules were investigated through nuclear magnetic resonance (NMR) spectroscopy. It was revealed that water, ethanol, and methanol as protic solvents can add to the formyl group of spiramycin molecules during standard solutions preparation while there was no evidence for the addition of acetonitrile and dimethyl sulfoxide (aprotic solvents). In addition, as time passed, the peak area of spiramycin decreased either in the spiked aqueous sample or milk sample while an increase in the peak area of HO-bound spiramycin was observed. After 96 h, more than 90% of spiramycin was converted to HO-bound spiramycin. In conclusion, we can propose the use of aprotic solvents for the preparation of spiramycin standard solutions especially when the prepared solutions are not used instantly. Moreover, ion transitions for both spiramycin and its HO-added form (843.6 / to 173.9 / and 861.5 / to 173.9 /, respectively) should be considered for the accurate quantification of spiramycin residue in aqueous samples such as milk.
液相色谱 - 串联质谱法（LC-MS/MS）是一种用于不同基质中药物残留分析的准确且特异的技术。多反应监测（MRM）方法对于检测醛类等药物具有高特异性和灵敏度，这些药物在样品制备阶段有可能发生质量变化，而这在分析过程中成为一个缺点。在本研究中，解决了作为醛类药物的螺旋霉素在牛奶基质中溶剂分子侵入其化学结构以及螺旋霉素稳定性的问题。此外，通过核磁共振（NMR）光谱研究了溶剂分子与螺旋霉素分子结合的位点。结果表明，在制备标准溶液时，作为质子溶剂的水、乙醇和甲醇可加成到螺旋霉素分子的甲酰基上，而没有证据表明乙腈和二甲基亚砜（非质子溶剂）会发生加成。此外，随着时间的推移，加标水样或牛奶样品中螺旋霉素的峰面积下降，而观察到与HO结合的螺旋霉素峰面积增加。96小时后，超过90%的螺旋霉素转化为与HO结合的螺旋霉素。总之，我们建议使用非质子溶剂来制备螺旋霉素标准溶液，特别是当制备的溶液不能立即使用时。此外，为了准确定量牛奶等水样中螺旋霉素残留，应考虑螺旋霉素及其加HO形式的离子跃迁（分别为843.6 / 到173.9 / 和861.5 / 到173.9 /）。
