Supercritical Fluid Nanospray Mass Spectrometry: II. Effects on Ionization
Supercritical Fluid Nanospray Mass Spectrometry: II. Effects on Ionization
复制标题
超临界流体纳喷雾质谱：II。
DOI：
10.1021/jasms.2c00372
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发表时间：
2023
影响因子：
3.2
通讯作者：
Edwards, James L.
中科院分区：
文献类型：
--
作者：
Mostafa, Mahmoud Elhusseiny;Hayes, Madisyn M.;Grinias, James P.;Bythell, Benjamin J.;Edwards, James L.
纳米喷雾超临界流体耦合到质谱仪（nSF-MS）使用90%的超临界流体CO2载体（sCO 2）已显示出增强的去溶剂化相比，传统的液体洗脱剂。25、50和75 μm内径（i.d.）的胶囊具有拉的发射极尖端提供了高的MS检测灵敏度。这里提出的是质子亲和力，疏水性和纳米发射器尖端尺寸对nSF-MS信号的影响的评价。这是使用一组具有丁基、己基、辛基和癸基链的伯胺、仲胺、叔胺和季胺作为分析物来完成的。单独分析每种胺类以评估疏水性和质子亲和力对信号强度的影响。该系统在0.1-100 μM的线性动态范围内显示出质量灵敏检测。结果表明，疏水性对信号响应的影响大于质子亲和力。使用75 μm发射器纳米喷雾所有胺类的混合物显示季胺信号不受竞争分析物的抑制。竞争电离观察伯，仲，叔胺。75 μ m和50 μm发射体表现出随着疏水性增加而增加的信号。令人惊讶的是，25 μm i.d.发射体产生的信号随着烷基链长度的增加而减小，这与常规理解相反。在低于500 nm的发射器中纳米喷射蒸发流体可能导致电离机制的差异。结果表明，90%sCO2与9.99%甲醇和0.01%甲酸产生快速的去溶剂化，高电离效率，低基质效应，这可能有利于复杂的生物基质分析。
Nanospraying supercritical fluids coupled to a mass spectrometer (nSF-MS) using a 90% supercritical fluid CO2carrier (sCO2) has shown an enhanced desolvation compared to traditional liquid eluents. Capillaries of 25, 50, and 75 μm internal diameter (i.d.) with pulled emitter tips provided high MS detection sensitivity. Presented here is an evaluation of the effect of proton affinity, hydrophobicity, and nanoemitter tip size on the nSF-MS signal. This was done using a set of primary, secondary, tertiary, and quaternary amines with butyl, hexyl, octyl, and decyl chains as analytes. Each amine class was analyzed individually to evaluate hydrophobicity and proton affinity effects on signal intensity. The system has shown a mass sensitive detection on a linear dynamic range of 0.1–100 μM. Results indicate that hydrophobicity has a larger effect on the signal response than proton affinity. Nanospraying a mixture of all amine classes using the 75 μm emitter has shown a quaternary amine signal not suppressed by competing analytes. Competing ionization was observed for primary, secondary, and tertiary amines. The 75 and 50 μm emitters demonstrated increased signal with increasing hydrophobicity. Surprisingly, the 25 μm i.d. emitter yielded a signal decrease as the alkyl chain length increased, contrary to conventional understanding. Nanospraying the evaporative fluid in a sub-500 nm emitter likely resulted in differences in the ionization mechanism. Results suggest that 90% sCO2with 9.99% methanol and 0.01% formic acid yielded fast desolvation, high ionization efficiency, and low matrix effect, which could benefit complex biological matrix analysis.