A universal ionization label for the APLI-(TOF)MS analysis of small molecules and polymers.
A universal ionization label for the APLI-(TOF)MS analysis of small molecules and polymers.
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用于小分子和聚合物 APLI-(TOF)MS 分析的通用电离标签。
DOI：
10.1002/anie.200804106
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发表时间：
2008
影响因子：
--
通讯作者：
O. Schmitz
中科院分区：
文献类型：
--
作者：
R. Schiewek;R. Mönnikes;V. Wulf;S. Gäb;K. Brockmann;T. Benter;O. Schmitz
对日益复杂的样品进行定性和定量测定的需求急剧增加，这对现代仪器分析构成了巨大的挑战。目前，对于复杂的有机样品，只有色谱或电泳分离与随后的质谱检测（MS）才能满足这些要求。对于联用气相色谱（GC）、液相色谱（LC）或毛细管电泳（CE）分离的质谱分析，分离的分析物分子的电离必须尽可能定量。对于不同分子量和极性的分析物，必须采用不同的电离方法。对于极性化合物，电喷雾电离（ESI）是小分子质谱分析的金标准，由于多次充电，也适用于大分子生物高达几千道尔顿（kDa）和中等极性的分析物有利于常压化学电离（APCI），而常压光电离（APPI）和掺杂辅助(DA)-APPI通常用于非极性物质的电离大气压激光电离（APLI），最近由我们的小组开发，显示出优异的灵敏度中等至非极性芳香族化合物这种对芳香族化合物的选择性来自于APLI的电离机制：通过调整激光功率密度，使其接近共振增强（1+ 1）多光子激发的阈值，即大约为1 MWcmÀ2，可以使基质化合物的多光子激发最小化。当波长为248nm的光子用于激发时，大多数基质化合物的线性吸收可以忽略不计。现成的小尺寸准分子激光器是足够强大的光源。对于有效共振双光子电离，芳烃的光谱特征是相当独特的：它们表现出强烈的线性吸收交叉
The drastically increased demand for qualitative and quantitative determinations of increasingly complex samples represents a tremendous challenge to modern instrumental analysis. Currently, for complex organic samples only chromatographic or electrophoretic separation with subsequent mass spectrometric detection (MS) fulfills these requirements. For MS analysis coupled with separation by gas chromatography (GC), liquid chromatography (LC), or capillary electrophoresis (CE), the ionization of the separated analyte molecules must be as quantitative as possible. Different ionization methods have to be used for analytes of different molecular weight and polarity.[1]For polar compounds, electrospray ionization (ESI) is the gold standard with respect to mass spectrometric analysis of small molecules and, because of multiple charging, of large biomolecules, as well.[2] Analytes of up to several thousand daltons (kDa) and of moderate polarity are favorably ionized by atmospheric-pressure chemical ionization (APCI),[3] while atmospheric-pressure photo-ionization (APPI) and dopantassisted (DA)-APPI are usually applied for the ionization of non-polar substances.[4] Atmospheric-pressure laser ionization (APLI), recently developed by our groups, shows an outstanding sensitivity for moderately to non-polar aromatic compounds.[5] This selectivity towards aromatic compounds arises from the ionization mechanism of APLI: Multiphoton excitation of matrix compounds is minimized by adjusting the laser power density close to the threshold of resonantly enhanced (1+ 1) multiphoton excitation, in other words, to roughly 1 MWcmÀ2. Linear absorption of most matrix compounds becomes negligible when photons with a wavelength of 248 nm are used for excitation. Readily available smallfootprint excimer lasers are sufficiently powerful light sources. With respect to efficient resonant two-photon ionization, the spectroscopic features of aromatic hydrocarbons are rather unique: They display strong linear absorption cross
影响因子：
4.3
作者：
Schiewek, Ralf;Lorenz, Matthias;Schmitz, Oliver J.
通讯作者：
Schmitz, Oliver J.