2P-04 PDF
Comparison of Atmospheric Pressure Laser Desorption/Ionization Using the Wavelength Range of 3 and 6 μm
Ionization efficiency of an aqueous solution of a peptide with AP-IR-MALDI was compared using two mid-infrared tunable lasers at the 3 and 6 µm-bands. A difference-frequency generation (DFG) laser was used as the 6 μm-band laser. An optical parametric oscillator was used as the 3 μm-band laser. Angiotensin II was dissolved in 0.1% trifluoroacetic acid aqueous solution at a concentration of 10 pmol/µL. An ion trap mass spectrometer was used, and its ion source was whose ESI ion source had been modified to an AP-IR-MALDI ion source. Dependences of the signal intensity of the [M + H]+ of angiotensin II on the wavelength and irradiated laser pulse energy was compared at the wavelength ranges of 3 and 6 µm. The highest signal intensity of [M + H]+ of angiotensin II was obtained at 2.88 μm and 6.00 μm, respectively. And the peak intensity of [M + H]+ measured at the wavelength of 6.00 µm was comparable to that measured at the wavelength of 2.88 µm. AP IR-MALDI using the DFG laser can be used as a novel way targeting biomolecules dissolved in low or no volatile solvents.