Bieri Stefan, Varesio Emmanuel, Veuthey Jean-Luc, Muñoz Orlando, Tseng Li-Hong, Braumann Ulrich, Spraul Manfred, Christen Philippe
Laboratory of Pharmaceutical Analytical Chemistry, School of Pharmaceutical Sciences EPGL, University of Geneva, 20 Bd d'Yvoy, 1211 Geneva 4, Switzerland.
Phytochem Anal. 2006 Mar-Apr;17(2):78-86. doi: 10.1002/pca.889.
Two fully automated HPLC-NMR methods are reported and compared for the structure elucidation of four isomeric tropane alkaloids from the stem-bark of an endemic Chilean plant, Schizanthus grahamii Gill. (Solanaceae). The first approach interfaced a conventional HPLC column to NMR by means of a loop storage unit. After elution with a mobile phase consisting of deuterated water and standard protonated organic solvents, the separated analytes were momentarily stored in a loop cassette and then transferred one-at-a-time to the NMR flow probe for measurements. The second strategy combined HPLC with parallel ion-trap MS detection and NMR spectroscopy using an integrated solid-phase extraction (SPE) unit for post-column analyte trapping. The SPE cartridges were dried under a gentle stream of nitrogen and analytes were sequentially eluted and directed to a cryogenically cooled flow-probe with an NMR-friendly solvent. The structures of the four isomeric alkaloids, 3alpha-senecioyloxy-7beta-hydroxytropane, 3alpha-hydroxy-7beta-angeloyloxytropane, 3alpha-hydroxy-7beta-tigloyloxytropane and 3alpha-hydroxy-7beta-senecioyloxytropane, were unambiguously determined by combining NMR assignments with MS data.
本文报道了两种全自动高效液相色谱-核磁共振联用（HPLC-NMR）方法，并对其进行了比较，用于从智利本土植物格拉汉姆氏蛾蝶花（茄科）茎皮中提取的四种异构托烷生物碱的结构解析。第一种方法通过一个定量环存储单元将常规HPLC柱与NMR连接。在用由重水和标准质子化有机溶剂组成的流动相洗脱后，分离出的分析物暂时存储在定量环盒中，然后一次转移一个到NMR流动探头进行测量。第二种策略将HPLC与平行离子阱质谱检测和NMR光谱相结合，使用集成固相萃取（SPE）单元进行柱后分析物捕集。SPE柱在温和的氮气流下干燥，分析物依次洗脱并导入配有对NMR友好溶剂的低温冷却流动探头。通过将NMR归属与MS数据相结合，明确确定了四种异构生物碱3α-千里光酰氧基-7β-羟基托烷、3α-羟基-7β-当归酰氧基托烷、3α-羟基-7β-惕各酰氧基托烷和3α-羟基-7β-千里光酰氧基托烷的结构。
