Anal Chem. 2010 Mar 15;82(6):2178-81. doi: 10.1021/ac902905v.
Presented here is a novel ambient ion source termed infrared laser ablation metastable-induced chemical ionization (IR-LAMICI). IR-LAMICI integrates IR laser ablation and direct analysis in real time (DART)-type metastable-induced chemical ionization for open air mass spectrometry (MS) ionization. The ion generation in the IR-LAMICI source is a two step process. First, IR laser pulses impinge the sample surface ablating surface material. Second, a portion of ablated material reacts with the metastable reactive plume facilitating gas-phase chemical ionization of analyte molecules generating protonated or deprotonated species in positive and negative ion modes, respectively. The successful coupling of IR-laser ablation with metastable-induced chemical ionization resulted in an ambient plasma-based spatially resolved small molecule imaging platform for mass spectrometry (MS). The analytical capabilities of IR-LAMICI are explored by imaging pharmaceutical tablets, screening counterfeit drugs, and probing algal tissue surfaces for natural products. The resolution of a chemical image is determined by the crater size produced with each laser pulse but not by the size of the metastable gas jet. The detection limits for an active pharmaceutical ingredient (acetaminophen) using the IR-LAMICI source is calculated to be low picograms. Furthermore, three-dimensional computational fluid dynamic simulations showed improvements in the IR-LAMICI ion source are possible.
这里介绍了一种新型的环境离子源，称为红外激光烧蚀亚稳态诱导化学电离（IR-LAMICI）。IR-LAMICI 将红外激光烧蚀和实时直接分析（DART）型亚稳态诱导化学电离集成在一起，用于开放空气质谱（MS）电离。IR-LAMICI 源中的离子生成是一个两步过程。首先，红外激光脉冲撞击样品表面，烧蚀表面材料。其次，一部分烧蚀材料与亚稳反应性羽流反应，促进分析物分子的气相化学电离，分别在正离子和负离子模式下生成质子化或去质子化物种。成功地将红外激光烧蚀与亚稳态诱导化学电离相结合，为质谱（MS）提供了基于环境等离子体的空间分辨小分子成像平台。通过对药片成像、筛选假药以及探测藻类组织表面的天然产物，探索了 IR-LAMICI 的分析能力。化学图像的分辨率取决于每个激光脉冲产生的凹坑大小，而不是亚稳气体射流的大小。使用 IR-LAMICI 源检测一种活性药物成分（对乙酰氨基酚）的检测限计算低至皮克级。此外，三维计算流体动力学模拟表明，IR-LAMICI 离子源可能会有所改进。
