Low-Temperature Plasma Probe for Ambient Desorption Ionization
Low-Temperature Plasma Probe for Ambient Desorption Ionization
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DOI：
10.1021/ac801641a
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发表时间：
2008-12-01
影响因子：
7.4
通讯作者：
Ouyang, Zheng
中科院分区：
文献类型：
--
作者：
Harper, Jason D.;Charipar, Nicholas A.;Ouyang, Zheng
研制了一种低温等离子体（LTP）探针。交流电场用于通过使用特别设计的电极配置来诱导介质阻挡放电。低温等离子体从探针中提取，在探针中，低温等离子体直接与被分析的样品相互作用，解吸和电离周围环境中的表面分子。这允许在不损坏样品或底层基质的情况下进行实验，并且在皮肤表面上进行生物分析的情况下，没有电击或可感知的加热。正离子或负离子是由各种纯态的化合物以及气态、溶液或冷凝相的混合物产生的，使用He、Ar、N-2或环境空气作为放电气体。发生有限的碎裂，尽管在分子放电气体的情况下碎裂比原子放电气体的情况大。LTP探针的有效性已通过记录聚乙烯中含有六氢-1，3，5-三嗪（RDX）和2，4，6-三硝基甲苯（TNT）的样品的特征质谱和串联质谱得到证实（PTFE）表面，检测限低至5 pg。其他性能特征，当使用商用离子阱质谱仪时，包括3-4个数量级线性动态范围。示范应用包括直接分析人体皮肤中的可卡因，直接测定药片中的活性成分，以及分析复杂生物样品中的有毒和治疗化合物。已经证明了直接从散装水溶液中电离化学品，其中检测限低至1 ppb。大表面积采样和通过在操作期间简单调整电极配置来控制破碎是该方法的其他已证明的特征。
A low-temperature plasma (LTP) probe has been developed for ambient desorption ionization. An ac electric field is used to induce a dielectric barrier discharge through use of a specially designed electrode configuration. The low-temperature plasma is extracted from the probe where it interacts directly with the sample being analyzed, desorbing and ionizing surface molecules in the ambient environment. This allows experiments to be performed without damage to the sample or underlying substirate and, in the case of bioloocal analysis on skin surfaces, without electrical shock or perceptible heating. Positive or negative ions are produced from a wide range of chemical compounds in the pure state and as mixtures in the gaseous, solution, or condensed phases, using He, Ar, N-2, or ambient air as the discharge gas. limited fragmentation occurs, although it is greater in the cases of the molecular than the atomic discharge gases. The effectiveness of the LTP probe has been demonstrated by recording characteristic mass spectra and tandem mass spectra of samples containing hexahydro-1,3,5-triazine,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT) from poly(tetrafluoroethylene) (PTFE) surfaces where limits of detection are as low as 5 pg. Other performance characteristics, when using a commercial ion trap mass spectrometer, include 3-4 orders of magnitude linear dynamic range in favorable cases. Demonstration applications include direct analysis of cocaine from human skin, determination of active ingredients directly in drug tablets, and analysis of toxic and therapeutic compounds in complex biological samples. Ionization of chemicals directly from bulk aqueous solution has been demonstrated, where limits of detection are as low as 1 ppb. Large surface area sampling and control of fragmentation by a simple adjustment of the electrode configuration during operation are other demonstrated characteristics of the method.