| abstract |
The invention enables measurement of a biosample without preprocessing, desorptive ionization of ions under the atmospheric pressure, and imaging at a spatial resolution of nm order. A sample object of measurement without preprocessing under the atmospheric pressure is, e.g., a biological tissue. An STM probe with an XYZ-axis drive piezoelectric element is vibrated vertically by a Z-direction drive at a frequency of several Hz to several kHz with amplitudes of several 10 µm to several mm, and brought into contact with the biosample at nm order depth to capture molecules of the biosample by the probe tip. A pulse high voltage is applied to the probe tip thereby realizing probe electrospray. The molecules of the sample captured by the probe tip are desorptively-ionized by Plasmon-assisted electrospray or infrared laser heating assist, and are mass-analyzed by orthogonal time-of-flight mass spectrometry or an ion trap mass spectrometer. The probe is scanned in the X- and Y-directions to produce repetitive vibration and the molecule image in the nm region is measured. In another mode, a probe is brought in contact with a droplet produced on the tip of the capillary connected to the exit of a liquid chromatograph, a liquid sample is captured, and electrospray is produced. |