Comprehensive analysis of alkenones and alkenoates by reversed phase HPLC-MS with unprecedented sensitivity and selectivity

通过反相 HPLC-MS 全面分析烯酮和烯酸酯，具有前所未有的灵敏度和选择性

• 批准号: 2234875
• 负责人: Yongsong Huang
• 金额: $ 30.44万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-15 至 2024-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2234875&HistoricalAwards=false
• 关键词: Comprehensive; analysis; alkenones; alkenoates; reversed

This project will develop sensitive and time-saving analytical methods to quantify an important class of organic compounds, long chain alkenones, in ocean and lake environments. Alkenones are produced only by microalgae belonging to the order Isochrysidales, with no other organisms known to make such compounds. Such unique compounds are termed biomarkers. Alkenone biomarkers are extremely resistant to break-down and have been found in geological sediments as old as 120 million years. Remarkably, alkenones measured from ocean and lake environments display consistent structural changes at different growth temperatures and also track aquatic photosynthetic productivity. Thus, measurement of alkenones in ancient sediments provides quantitative insights to past climate and aquatic productivity. That information helps predict future changes in climate and aquatic ecosystems in the era of global warming induced by human activities. The project Broader Impacts include support for a Ph.D. graduate student, undergraduate student researchers, and a high school summer intern. Traditionally, alkenones are analyzed using gas chromatograph coupled to a flame ionization detector (GCFID), or in extremely low concentration samples, gas chromatograph-chemical ionization mass spectrometry (GCCIMS). However, GCFID is non-selective (i.e., cannot exclude interferences if present) and has relatively low sensitivity and requires tedious sample cleanup for complex samples, whereas GCCIMS displays non-linear and often variable responses to alkenones, which increases analytical uncertainties. The proposed research takes advantage of the latest advances in high pressure liquid chromatograph mass spectrometry (HPLCMS). Preliminary data shows that the new reversed phase HPLC-MS based analytical methods will have much higher sensitivity (up to two orders of magnitudes), and exceptional selectivity (i.e., strong capability to exclude interferences) for analyzing alkenones. The proposed work includes testing various liquid chromatographic conditions (solvent elution schemes, column types) to optimize the chromatographic separation of long chain alkenones. Mass spectrometry parameters including two different ionization modes (atmospheric pressure chemical ionization, or electrospray ionization), and various electronic settings will also be optimized. A series of algal culture samples will be grown at different temperatures and measured using the traditional GCFID method. These culture samples will then be used as standards for calibration between the authentic alkenone proxy values and HPLCMS based measurements. A large set of global ocean surface sediments collected from diverse ocean environments and containing variable interferences will be analyzed to fully validate the new reversed phase HPLCMS methods.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目将开发敏感且节省时间的分析方法，以量化海洋和湖泊环境中一类重要的有机化合物，长链烷烃。烯烃仅由属于等速剂级的微藻产生，没有其他生物可以生产这种化合物。这种独特的化合物被称为生物标志物。烯酮生物标志物对破裂具有极大的抵抗力，并且在年龄的1.2亿年中被发现。值得注意的是，从海洋和湖泊环境测量的烯酮在不同的生长温度下显示出一致的结构变化，并跟踪水生光合生产力。因此，在古代沉积物中测量烯酮为过去的气候和水生生产率提供了定量的见解。该信息有助于预测人类活动引起的全球变暖时代的气候和水生生态系统的未来变化。该项目更广泛的影响包括对博士学位的支持。研究生，本科生研究人员和高中暑期实习生。 传统上，使用与火焰电离探测器（GCFID）或极低浓度样品（气体色谱化学电离质谱法（GCCIMS））分析烷烃。但是，GCFID是非选择性的（即，如果存在，则不能排除干扰），并且具有相对较低的灵敏度，并且需要对复杂样品进行乏味的样品清理，而GCCIMS则显示非线性响应，通常对烷烃的响应，从而增加了分析不确定性。拟议的研究利用了高压液相色谱质谱法（HPLCMS）的最新进展。初步数据表明，新的基于HPLC-MS的相反相位的分析方法将具有更高的灵敏度（最多两个幅度的幅度），并且具有出色的选择性（即，排除干扰性的强大能力）用于分析烷烃。拟议的工作包括测试各种液态色谱条件（溶剂洗脱方案，色谱柱类型），以优化长链烷烃的色谱分离。质谱参数包括两种不同的电离模式（大气压化学电离或电喷雾电离）以及各种电子设置也将得到优化。一系列藻类培养样品将在不同的温度下生长，并使用传统的GCFID方法进行测量。然后，这些培养样品将被用作标准的标准，以校准正宗的烯酮代理值和基于HPLCMS的测量值。将分析从各种海洋环境中收集的大量全球海洋表面沉积物，并包含可变干扰，以充分验证新的反向相反阶段的HPLCMS方法。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛的影响审查标准来通过评估来通过评估来支持的。