Usmanov Dilshadbek T, Ashurov Khatam B, Ninomiya Satoshi, Hiraoka Kenzo, Wada Hiroshi, Nakano Hiroshi, Matsumura Masaya, Sanada-Morimura Sachiyo, Nonami Hiroshi
Clean Energy Research Center, University of Yamanashi, 4-3-11, Takeda, Kofu, Yamanashi, 400-8511, Japan.
Institute of Ion-Plasma and Laser Technologies, Durmon Yoli Street 33, 100125, Tashkent, Uzbekistan.
Rapid Commun Mass Spectrom. 2018 Mar 15;32(5):407-413. doi: 10.1002/rcm.8045.
Probe electrospray ionization (PESI) is only applicable to liquid or wet samples. In this study, a sheath-flow PESI method for remote sampling mass spectrometry that can be applied to dry samples was developed.
An acupuncture needle (0.12 mm outer diameter, 700 nm tip diameter) was inserted into a gel-loading tip with a 0.1 mm protrusion out of the tip. Analytes were extracted by filling the latter tip with solvent and softly touching the sample surface for a short time (<1 s). A high voltage was applied to the acupuncture needle, and mass spectra of analytes were obtained by self-aspirating electrospray.
Dry samples, such as lines of ballpoint pen ink on paper, pharmaceutical tablets, instant coffee, brown rice, and narcotics, gave strong ion signals. The sample carryover was negligible. The sequential electrospray was observed to be similar to conventional PESI. The limits of detection (LODs) for morphine and rhodamine B were found to be of the order of picograms.
Because of its simplicity and versatility, sheath-flow PESI is a promising technique for on-site and nondestructive profile analysis of dry samples with bulky and complicated shapes, with a spatial resolution of ~0.3 mm.
探针电喷雾电离（PESI）仅适用于液体或湿样品。在本研究中，开发了一种可应用于干燥样品的鞘流PESI远程采样质谱方法。
将一根外径0.12毫米、尖端直径700纳米的针灸针插入一个凝胶上样尖端，该尖端伸出0.1毫米。通过用溶剂填充后一个尖端并在短时间内（<1秒）轻轻接触样品表面来提取分析物。向针灸针施加高电压，并通过自吸电喷雾获得分析物的质谱图。
干燥样品，如纸上的圆珠笔墨水线、药片、速溶咖啡、糙米和麻醉品，给出了很强的离子信号。样品残留可忽略不计。观察到连续电喷雾与传统PESI相似。吗啡和罗丹明B的检测限为皮克量级。
由于其简单性和通用性，鞘流PESI是一种很有前景的技术，可用于对形状庞大且复杂的干燥样品进行现场无损轮廓分析，空间分辨率约为0.3毫米。
