title: Physical properties of the probe electrospray ionization (PESI) needle applied to the biological samples.
abstract: Probe electrospray ionization (PESI) is a recently developed technique that uses a fine solid needle as a probe for sampling biological materials. In this study, we quantified the volume of liquid sample picked up by the solid needle with the tip diameter of approximately 700 nm and the apex angle of approximately 60 degrees. The amounts of low-viscosity samples (rat urine) loaded on the tip of the needle by a single stroke were 0.35 +/- 0.09 pl. Interestingly, the amount of liquid adhered to the tip did not significantly depend on the protein concentration, but viscosity and surface tension of the sample. Under these conditions, we successfully obtained mass spectra for each biological sample.
authors.affiliation: Department of Anatomy and Cell Biology, Interdisciplinary School of Medicine and Engineering, The University of Yamanashi, 1110 Shimo-Kateau, Chuo, Yamanashi 409-3898, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yoshimura
authors.forename: Lee Chuin
authors.initials: LC
authors.lastname: Chen
authors.forename: Daiki
authors.initials: D
authors.lastname: Asakawa
authors.forename: Kenzo
authors.initials: K
authors.lastname: Hiraoka
authors.forename: Sen
authors.initials: S
authors.lastname: Takeda
mesh_terms: D000818:Animals; D001923:Brain Chemistry; D008099:Liver / Q000737:chemistry; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009339:Needles; D051381:Rats; D018401:Sample Size; D044967:Serum / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000295:instrumentation* / Q000379:methods; D013500:Surface Tension; D014556:Urine / Q000737:chemistry; D014783:Viscosity