Jiangxi Key Laboratory for Mass Spectrometry and Instrumentation, College of Chemistry, Biology and Material Sciences, East China Institute of Technology, Nanchang, Jiangxi Province 330013, P. R. China.
Analyst. 2011 Dec 7;136(23):4977-85. doi: 10.1039/c1an15483d. Epub 2011 Oct 4.
Unlike the extractive electrospray ionization (EESI) technique described elsewhere, a corona discharge instead of electrospray ionization has been utilized to charge a neutral solvent spray under ambient conditions for the generation of highly charged microdroplets, which impact a neutral sample plume for the extractive ionization of the analytes in raw samples without any sample pretreatment. Using the positive ion mode, molecular radical cations were easily generated for the detection of non-polar compounds (e.g., benzene, cyclohexane, etc.), while protonated molecular ions of polar compounds (e.g., acetonitrile, acetic ether) were readily produced for the detection. By dispensing the matrix in a relatively large space, this method tolerates highly complex matrices. For a given sample such as lily fragrances, more compounds were detected by the method established here than the EESI technique. An acceptable relative standard deviation (RSD 8.9%, n = 11) was obtained for the direct measurement of explosives (10 ppb) in waste water samples. The experimental data demonstrate that this method could simultaneously detect both polar and non-polar analytes with high sensitivity, showing promising applications for the rapid detection of a wide variety of compounds present in complex matrices.
与其他地方描述的萃取电喷雾电离 (EESI) 技术不同，本研究采用电晕放电而不是电喷雾电离来对中性溶剂喷雾进行充电，从而在环境条件下产生带高电荷的微液滴，这些微液滴与中性样品射流碰撞，对原始样品中的分析物进行萃取电离，而无需对样品进行任何预处理。采用正离子模式，很容易生成分子自由基阳离子，从而检测非极性化合物（例如苯、环己烷等），同时也很容易产生极性化合物（例如乙腈、乙酸乙酯）的质子化分子离子进行检测。通过在相对较大的空间中分配基质，该方法可以容忍高度复杂的基质。对于给定的样品（例如百合香精），与 EESI 技术相比，该方法可以检测到更多的化合物。对于废水中爆炸物（10 ppb）的直接测量，该方法可获得可接受的相对标准偏差 (RSD 8.9%，n = 11)。实验数据表明，该方法可以同时以高灵敏度检测极性和非极性分析物，有望用于快速检测复杂基质中存在的各种化合物。
