• Bulletin of the Korean Chemical Society
• /
• 제30권8호
• /
• pp.1864-1866
• /
• 2009

• Bulletin of the Korean Chemical Society
• /
• 제25권6호
• /
• pp.878-880
• /
• 2004

Revered-phase LC-electrospray ionization mass spectrometry was used to selectively determine enalapril from plasma with minimal sample preparation. Detection limit of the method was 1 ng/mL. Precision (within day and between days) and accuracy of the method at various concentrations were acceptable. The analytical technique was used for pharmacokinetic studies after administration of enalapril to human test subjects.

• Bulletin of the Korean Chemical Society
• /
• 제7권2호
• /
• pp.97-99
• /
• 1986

Calculated ionization potential, electron affinity, electron density and bond order of some thiophene derivatives have been obtained and correlated with the inhibition of corrosion produced by these substances as evaluated by polarization curves. It is apparent that such quantities as the electron density or ionization potential play an important role. The calculation was carried out by the Extended Huckel method for the series of substituted thiophene derivatives.

• Bulletin of the Korean Chemical Society
• /
• 제21권4호
• /
• pp.401-404
• /
• 2000

Matrix/Surface-assisted laser desorption/ionization (M/SALDI) mass spectrometry of polypropylene glycol and polystyrene, directly deposited on graphite plate, is demonstrated. Graphite plate is effective both as an en-ergy transfer medium and robu st sampling support for LDI of polymers. Mass spectra ofpolymers can be easily obtained due to homogeneous distribution on graphite surface and their ion signals are long-lived by large ef-fective desorption volume enough to investigate M/SALDI process.

• Bulletin of the Korean Chemical Society
• /
• 제23권7호
• /
• pp.929-930
• /
• 2002

• Bulletin of the Korean Chemical Society
• /
• 제24권1호
• /
• pp.144-146
• /
• 2003

• Bulletin of the Korean Chemical Society
• /
• 제20권7호
• /
• pp.843-845
• /
• 1999

• Bulletin of the Korean Chemical Society
• /
• 제20권3호
• /
• pp.367-369
• /
• 1999

• Bulletin of the Korean Chemical Society
• /
• 제20권3호
• /
• pp.370-372
• /
• 1999

• Bulletin of the Korean Chemical Society
• /
• 제33권5호
• /
• pp.1561-1565
• /
• 2012

The structures of the four lowest alanine conformers, along with their radical cations and the effect of ionization on the intramolecular proton transfer process, are studied using the density functional theory and MP2 method. The energy order of the radical cations of alanine differs from that of the corresponding neutral conformers due to changes in the basicity of the $NH_2$ group upon ionization. Ionization favors the intramolecular proton transfer process, leading to a proton-transferred radical-cation structure, [$NH_3{^+}-CHCH_3-COO{\bullet}$], which contrasts with the fact that a proton-transferred zwitterionic conformer is not stable for a neutral alanine in the gas phase. The energy barrier during the proton transfer process is calculated to be about 6 kcal/mol.