Imaging mass spectrometry (IMS) is a powerful technique that enables analysis of various molecular species at a high spatial resolution with low detection limits. In contrast to the matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS) approach, surface‐assisted laser desorption/ionization (SALDI) can be more effective in the detection of small molecules due to the absence of interfering background signals in low m/z ranges. We developed a functionalized TiO₂ nanowire as a solid substrate for IMS of low‐molecular‐weight species in plant tissues. We prepared TiO₂ nanowires using an inexpensive modified hydrothermal process and subsequently functionalized them chemically with various silane analogs to overcome the problem of superhydrophilicity of the substrate. Chemical modification changed the selectivity of imprinting of samples deposited on the substrate surface and thus improved the detection limits. The substrate was applied to image distribution of the metabolites in very fragile specimens such as the petal of Catharanthus roseus. We observed that the metabolites are distributed heterogeneously in the petal, which is consistent with previous results reported for the C. roseus plant leaf and stem. The intermediates corresponding to the biosynthesis pathway of some vinca alkaloids were clearly shown in the petal. We also performed profiling of petals from five different cultivars of C. roseus plant. We verified the semi‐quantitative capabilities of the imprinting/imaging approach by comparing results using the LC‐MS analysis of the plant extracts. This suggested that the functionalized TiO₂ nanowire substrate‐based SALDI is a powerful technique complementary to MALDI‐MS.

中文翻译：

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使用功能化的氧化钛纳米线基质用于表面辅助激光解吸/电离成像质谱法可视化长春花花瓣中的长春花生物碱

成像质谱（IMS）是一项强大的技术，能够以高空间分辨率和低检测限对各种分子种类进行分析。与基质辅助激光解吸/电离质谱（MALDI-MS）方法相比，由于在低浓度下不存在干扰背景信号，表面辅助激光解吸/电离（SALDI）可以更有效地检测小分子。m / z范围。我们开发了功能化的TiO ₂纳米线作为植物组织中低分子量物种IMS的固体基质。我们准备了TiO ₂纳米线使用廉价的改良水热工艺，随后用各种硅烷类似物对其进行化学功能化，从而克服了基材的超亲水性问题。化学修饰改变了沉积在基板表面上的样品压印的选择性，从而提高了检测限。该基质被应用于代谢产物在非常脆弱的标本中的图像分布，例如Catharanthus roseus的花瓣。我们观察到代谢物在花瓣中的分布不均，这与先前报道的玫瑰假丝酵母的结果一致植物的叶子和茎。花瓣中清楚地显示出与某些长春花生物碱的生物合成途径相对应的中间体。我们还进行从五个不同品种的花瓣纹长春花植物。通过使用植物提取物的LC-MS分析结果进行比较，我们验证了印迹/成像方法的半定量功能。这表明功能化的基于TiO ₂纳米线基材的SALDI是对MALDI-MS的有力补充。