Data quality in tissue analysis using desorption electrospray ionization
Data quality in tissue analysis using desorption electrospray ionization
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DOI：
10.1007/s00216-011-5249-z
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发表时间：
2011-10-01
影响因子：
4.3
通讯作者：
Cooks, R. Graham
中科院分区：
文献类型：
--
作者：
Dill, Allison L.;Eberlin, Livia S.;Cooks, R. Graham
最近质谱（MS）在组织分析中的应用激增，特别是使用环境电离技术的基于脂质的组织成像。最近的增长突出了需要检查样品处理，储存条件和实验方案对所获得的数据质量的影响。变量，如冷冻前的时间，在器官切除后，在-80 ℃的存储时间，在室温下存储的时间，加热，和冻/融循环进行了研究，其对解吸电喷雾电离（DESI）-MS使用小鼠大脑获得的数据质量的影响。此外，还检查了组织厚度、干燥时间和仪器条件等分析变量对EST-MS数据的影响。虽然与取出后立即冷冻相比，在室温下放置1小时后小鼠脑组织的DESI-MS脂质谱没有立即发生变化，但在-80摄氏度下储存7个月后，组织样本之间出现了微小变化。在室温下储存的组织切片中，通过脂肪酸二聚体的出现在24小时内观察到降解，这表明脂肪酸浓度高，而相比之下，在-80 ℃下储存7个月的那些切片没有显示出显著的降解。组织切片还经历了多达6次冻融循环，并且在每个循环后显示出降解增加。此外，将组织块置于50 ℃温度下，并在特定时间点进行分析。在短短的2小时内，观察到降解的形式增加的脂肪酸二聚体的形成，表明酶的过程中形成游离脂肪酸仍然活跃的组织。我们已经将这些二聚体与高浓度的游离脂肪酸存在于组织中，在SDS-MS实验。还研究了分析变量，如组织厚度和在氮气下干燥的时间，在10至25 μ m的厚度下得到的曲线没有变化，并且在干燥器中仅20分钟后获得最佳信号。实验条件，如源参数，喷雾溶剂，和样品表面都被证明会影响数据的质量。截面（相对标准偏差（%RSD），0.44-7.2%）和样品内（%RSD，4.0-8.0%）重现性数据显示了高质量的信息，CNO-MS提供。总体而言，本文研究的许多变量表明，EST-MS是一种稳健的技术，样品储存条件对获得的数据影响最大，并且在室温储存期间发生不可接受的样品降解。
There has been a recent surge in applications of mass spectrometry (MS) to tissue analysis, particularly lipid-based tissue imaging using ambient ionization techniques. This recent growth highlights the need to examine the effects of sample handling, storage conditions, and experimental protocols on the quality of the data obtained. Variables such as time before freezing after organ removal, storage time at -80 degrees C, time stored at room temperature, heating, and freeze/thaw cycles were investigated for their effect on the data quality obtained in desorption electrospray ionization (DESI)-MS using mouse brain. In addition, analytical variables such as tissue thickness, drying times, and instrumental conditions were also examined for their impact on DESI-MS data. While no immediate changes were noted in the DESI-MS lipid profiles of the mouse brain tissue after spending 1 h at room temperature when compared to being frozen immediately following removal, minor changes were noted between the tissue samples after 7 months of storage at -80 degrees C. In tissue sections stored at room temperature, degradation was noted in 24 h by the appearance of fatty acid dimers, which are indicative of high fatty acid concentrations, while in contrast, those sections stored at -80 degrees C for 7 months showed no significant degradation. Tissue sections were also subjected to up to six freeze/thaw cycles and showed increasing degradation following each cycle. In addition, tissue pieces were subjected to 50 degrees C temperatures and analyzed at specific time points. In as little as 2 h, degradation was observed in the form of increased fatty acid dimer formation, indicating that enzymatic processes forming free fatty acids were still active in the tissue. We have associated these dimers with high concentrations of free fatty acids present in the tissue during DESI-MS experiments. Analytical variables such as tissue thickness and time left to dry under nitrogen were also investigated, with no change in the resulting profiles at thickness from 10 to 25 mu m and with optimal signal obtained after just 20 min in the dessicator. Experimental conditions such as source parameters, spray solvents, and sample surfaces are all shown to impact the quality of the data. Inter-section (relative standard deviation (%RSD), 0.44-7.2%) and intra-sample (%RSD, 4.0-8.0%) reproducibility data show the high quality information DESI-MS provides. Overall, the many variables investigated here showed DESI-MS to be a robust technique, with sample storage conditions having the most effect on the data obtained, and with unacceptable sample degradation occurring during room temperature storage.