New Mexico State University Nannochloropsis Negative Collection - Mass spectral peak list/Nanno_High_2_neg

We illustrate a detailed compositional characterization of hydrothermal liquefaction (HTL) oils derived from two biochemically distinct microalgae, Nannochloropsis gaditana and Chlorella sp. (DOE 1412), for a range of reaction temperature as observed by high-resolution electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The unique capability to unequivocally derive molecular formulae directly from FT-ICR MS-measured mass-to- charge ratio (for several thousand compounds in each oil) shows that lipids are completely reacted/converted for any reaction temperature above 200 degrees C and reveals the formation of non-lipid reaction products with increasing temperature. Specifically, lipid-rich oil is obtained at low reaction temperature (less than 225 degrees C) for both microalgal strains. For positive ion mode, the major lipid components in Chlorella sp. and N. gaditana HTL oils are betaine lipids and acylglycerols, respectively. Acidic species in the HTL oils (observed by negative ion mode) are dominated by free fatty acids (FFA) regardless of reaction temperature. HTL oils obtained at higher-temperatures (ge 225 degrees C) are comprised of a variety of basic nitrogen- and oxygen-containing compounds that originate from protein and carbohydrate degradation at elevated temperature. Similar structural features are observed for the abundant nitrogen heterocyclics between the two strains with slightly lower carbon number for Chlorella sp., overall.本研究针对两种生化特性迥异的微藻——微拟球藻（Nannochloropsis gaditana）与小球藻属（Chlorella sp.，DOE 1412）的水热液化（hydrothermal liquefaction, HTL）油，借助高分辨电喷雾电离傅里叶变换离子回旋共振质谱（ESI FT-ICR MS），对不同反应温度梯度下的样品开展了详细组成表征分析。该质谱技术可直接基于FT-ICR MS测得的质荷比，精准无歧义地推导单一样品中数千种组分的分子式，这一特性揭示：当反应温度高于200℃时，所有脂质均被完全反应或转化，且随着温度升高会生成非脂质类反应产物。具体而言，两种微藻在较低反应温度（低于225℃）下均可获得富含脂质的液化油产物。在正离子模式下，小球藻属与微拟球藻HTL油中的主要脂质组分分别为甜菜碱脂与酰基甘油。通过负离子模式检测到的HTL油中酸性组分，无论反应温度如何，均以游离脂肪酸（free fatty acids, FFA）为主。当反应温度≥225℃时，所得HTL油包含多种碱性含氮与含氧化合物，此类组分源自高温下蛋白质与碳水化合物的降解产物。整体而言，两种微藻的HTL油中均存在大量氮杂环化合物，且结构特征相似，但小球藻属产物的碳数整体略低于微拟球藻。