Water radical cations, (H₂O)_n^+•, have attracted considerable attention owing to their potential practical applications in analytical chemistry, structural chemistry, radiotherapy, and radiochemistry. Recently, atmospheric pressure chemical ionization has emerged as a versatile method for direct mass spectrometric analysis. Usually, H₃O⁺ is the major proton donor during ionization and only the pseudo molecular ion peaks, instead of molecular ions are detected. In this work, (H₂O)₂^+• ions with high oxidizability and reactivity were generated using hydrothermally grown TiO₂ nanoneedle arrays in combination with a linear ion trap mass spectrometer under low operating voltage and applied to the direct mass spectrometric analysis of a mixture of volatile aromatic hydrocarbons. (H₂O)₂^+• ions were generated with a high absolute ion current of up to 1.07 × 10⁵ counts/s at atmospheric pressure. Using the generated (H₂O)₂^+• as the primary ion permitted the tandem mass spectrometric analysis of a mixed vapor sample of aromatic hydrocarbons.

中文翻译：

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基于电晕放电的TiO2-纳米簇阵列在大气中快速生成水自由基阳离子以用于芳烃检测

氢自由基阳离子（H ₂ O）_n ^+•由于其在分析化学，结构化学，放射疗法和放射化学中的潜在实际应用而备受关注。最近，大气压化学电离已经成为直接质谱分析的一种通用方法。通常，H ₃ O ⁺是电离过程中的主要质子供体，并且仅检测到假分子离子峰，而不是分子离子。在这项工作中，使用水热生长的TiO ₂生成了具有高氧化性和反应性的（H ₂ O）₂ ^+•离子。纳米针阵列与线性离子阱质谱仪在低工作电压下结合，可用于挥发性芳香烃混合物的直接质谱分析。（H ₂ O）₂ ^+•离子 在大气压下以高达1.07×10 ⁵ counts / s的高绝对离子流生成。使用生成的（H ₂ O）₂ ^+•作为主要离子，可以对芳香烃的混合蒸气样品进行串联质谱分析。