Micro-electrospray with stainless steel emitters.
The physical processes underlying micro-electrospray (micro-ES) performance were investigated using a stainless steel (SS) emitter with a blunt tip. Sheathless micro-ES could be generated at a blunt SS tip without any tapering or sanding if ESI conditions were optimized. The Taylor cone was found to shrink around the inner diameter of the SS tubing, which permitted a low flow rate of 150 nL/min for sheathless microspray on the blunt tip (100 microm i.d. x 400 microm o.d.). It is believed that the wettability and/or hydrophobicity of SS tips are responsible for their micro-ES performance. The outlet orifice was further nipped to reduce the size of the spray cone and limit the flow rate to 50-150 nL/min, resulting in peptide detection down to attomole quantities consumed per spectrum. The SS emitter was also integrated into a polymethylmethacrylate microchip and demonstrated satisfactory performance in the analysis and identification of a myoglobin digest.
Shui
Wenqing
W
Department of Chemistry, Fudan University, Shanghai 200433, China.
Yu
Yanling
Y
Xu
Xuejiao
X
Huang
Zhenyu
Z
Xu
Guobing
G
Yang
Pengyuan
P
D006096:Gramicidin / Q000032:analysis; D006801:Humans; D006868:Hydrolysis; D008838:Microcomputers; D009211:Myoglobin / Q000032:analysis; D019904:Polymethyl Methacrylate; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation*; D013193:Stainless Steel; D014357:Trypsin
D009211:Myoglobin; D013193:Stainless Steel; D006096:Gramicidin; D019904:Polymethyl Methacrylate; D014357:Trypsin