Liu Qian-Bao, Lu Jing-Guang, Jiang Zhi-Hong, Zhang Wei, Li Wen-Jia, Qian Zheng-Ming, Bai Li-Ping
State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau, China.
Guangdong-Hong Kong-Macao Joint Laboratory of Respiratory Infectious Disease, Macau University of Science and Technology, Taipa, Macau, China.
Front Chem. 2022 Mar 24;10:862007. doi: 10.3389/fchem.2022.862007. eCollection 2022.
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is a sensitive surface analytical technology, which can simultaneously acquire diverse chemical components and their precise locations on the surfaces of samples without any requirements for chemical damage pretreatments or additional matrices. Commonly, the quality control of TCMs (traditional Chinese medicines) is limited by the qualitative and quantitative evaluations of the specifically extractive constituents. In this study, a practical sample preparation strategy named two-layered media embedding sample preparation was developed to obtain ideal freezing sections of dried materials of . Meanwhile, the well-established sample preparation method was applied for chemical profiling and imaging of natural (NCS) and cultured (CCS) by using TOF-SIMS. More than 200 components were tentatively identified and imaged in NCS and CCS at the same time. Mass spectrometry imaging revealed that most components have even distributions in caterpillars of , while TAGs, DAGs, MAGs, and FAs only have distributions outside caterpillars' digestive chambers. This is the first time that components were imaged for to exhibit the chemical distributions which have never been achieved by other analytical techniques so far. In addition, chemometrics was used to simplify and explain the massive TOF-SIMS mass data sets, which revealed the high chemical similarity between CCS and NCS. Furthermore, the relative quantification of TOF-SIMS data showed that CCS has comparable proportions of amino acids, nucleosides, monosaccharides, sphingolipids, sterols and other principles to NCS except for fatty acids, glycerides and glycerophospholipids. The higher amounts of TAGs and DAGs in CCS were confirmed by quantitative H-NMR, indicating reliable relative quantification of TOF-SIMS. In general, our research developed a novel approach of TOF-SIMS for chemical analysis of TCMs, and its successful application in comparative study of CCS and NCS suggested that TOF-SIMS is an advanced and promising analytical technology for the research of TCMs.
飞行时间二次离子质谱（TOF-SIMS）是一种灵敏的表面分析技术，它能够在无需对样品进行化学损伤预处理或添加额外基质的情况下，同时获取样品表面的多种化学成分及其精确位置。通常，中药的质量控制受限于特定提取物成分的定性和定量评估。在本研究中，开发了一种名为双层介质包埋样品制备的实用样品制备策略，以获得干燥材料的理想冰冻切片。同时，采用成熟的样品制备方法，利用TOF-SIMS对天然（NCS）和养殖（CCS）进行化学剖析和成像。同时在NCS和CCS中初步鉴定并成像了200多种成分。质谱成像显示，大多数成分在的毛虫中分布均匀，而TAGs、DAGs、MAGs和FAs仅分布在毛虫消化腔之外。这是首次对的成分进行成像，以展示其化学分布，而这是目前其他分析技术从未实现过的。此外，化学计量学被用于简化和解释大量的TOF-SIMS质谱数据集，结果表明CCS和NCS之间具有高度的化学相似性。此外，TOF-SIMS数据的相对定量显示，除脂肪酸、甘油酯和甘油磷脂外，CCS与NCS在氨基酸、核苷、单糖、鞘脂、甾醇和其他成分的比例相当。定量H-NMR证实了CCS中TAGs和DAGs的含量较高，表明TOF-SIMS的相对定量可靠。总体而言，我们的研究开发了一种用于中药化学分析的新型TOF-SIMS方法，其在CCS和NCS比较研究中的成功应用表明，TOF-SIMS是一种用于中药研究的先进且有前景的分析技术。
