Probe electrospray ionization (PESI) is a recently developed ESI-based ionization technique which generates electrospray from the tip of a solid needle. In this study, we have applied PESI interfaced with a time of flight mass spectrometer (TOF-MS) for direct profiling of phytochemicals in a section of a tulip bulb in different regions, including basal plate, outer and inner rims of scale, flower bud and foliage leaves. Different parts of tulip petals and leaves have also been investigated. Carbohydrates, amino acids and other phytochemicals were detected. A series of in vivo PESI-MS experiments were carried out on the second outermost scales of four living tulip bulbs to monitoring the change of carbohydrate content during the first week of initial growth. The breakdown of carbohydrates was observed which was in accordance with previous reports achieved by other techniques. This study has indicated that PESI-MS can be used for rapid and direct analysis of phytochemicals in living biological systems with advantages of low sample consumption and little sample preparation. Therefore, PESI-MS can be a new choice for direct analysis/profiling of bioactive compounds or monitoring metabolic changes in living biological systems.

探针电喷雾电离 (PESI) 是最近开发的基于 ESI 的电离技术，它从实心针的尖端产生电喷雾。在这项研究中，我们将 PESI 与飞行时间质谱仪 (TOF-MS) 结合使用，对不同区域的郁金香球茎部分中的植物化学物质进行直接分析，包括基底板、鳞片的外缘和内缘、花蕾和树叶。还研究了郁金香花瓣和叶子的不同部分。检测到碳水化合物、氨基酸和其他植物化学物质。在四个活郁金香球茎的第二个最外层尺度上进行了一系列体内 PESI-MS 实验，以监测初始生长第一周期间碳水化合物含量的变化。观察到碳水化合物的分解，这与通过其他技术实现的先前报告一致。本研究表明，PESI-MS 具有样品消耗量少、样品制备量少的优点，可用于活生物系统中植物化学物质的快速、直接分析。因此，PESI-MS 可以成为直接分析/分析生物活性化合物或监测生物系统代谢变化的新选择。