Absorption Spectra Of Amino Acids Research Articles

Remote terahertz spectroscopy from extended two-color plasma filaments: The ALTESSE 2 project

Coherent time-domain spectroscopy (TDS) using terahertz radiation is valuable for fundamental science, security, and medical applications. This study investigates the performance of air-biased coherent detection terahertz spectroscopy (ABCD-THz) when an extended plasma filament is created in the air over long distances. We report on the latest results obtained within the follow-up of the ALTESSE project (Bergé L. et al., EPL, 126 (2019) 24001) whose objective is to measure a set of spectral signatures characterizing suspicious materials over meter-long distances. As one of the most critical steps towards routinely applying this technique, we verified the feasibility of a remote THz time-domain spectroscopy by loosely focusing two-color ultrashort laser pulses at more than 3 meters from the laser source. The absorption spectra of amino acids and explosives analyzed in such a filamentation geometry are compared with those obtained using a standard ABCD scheme where the plasma is generated at much shorter distances of .

Change in the UV-VIS Absorbance of Amino Acids as a Result of Femtosecond Laser Irradiation

Problems such as genetic damage should be considered in the medical application of lasers. Pho- tochemical damage to living tissue is caused by high-photon energy light. Changes in the UV-VIS absorbance of amino acids by femtosecond laser irradiation are investigated in the present study. Ul- traviolet absorption spectra of amino acids were measured following their irradiation by femtosec- ond laser. The results indicate that changes in ultraviolet absorption appeared at a peak intensity above 70 GW/cm 2 , suggesting that a change in the chemical structure was caused by multiphoton absorption during the femtosecond laser irradiation.

Identification of peptides containing tryptophan, tyrosine, and phenylalanine using photodiode-array spectrophotometry

The characteristic absorption spectra of aromatic amino acids between 240 and 310 nm were used to identify tryptophan, tryosine, and phenylalanine-containing peptides. In acidic solution, the absorption spectra of these amino acids exhibit minima or maxima at 255, 270, and 286 nm. Based on these characteristics, the content of the aromatic amino acid in peptide can be estimated. For this study, 2 nmol of tryptic peptides from human apolipoprotein A-1 was separated by high-performance liquid chromatography using a reverse-phase column. The peptide fragments were monitored by a photodiode-array spectrophotometer. This new approach offers a rapid, simple, sensitive, and direct identification of peptides containing aromatic amino acids. Those containing Trp, which may be of interest for DNA sequencing and important in sequence analysis of proteins, can be selectively purified using this technique.

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THE ABSORPTION SPECTRA OF AMINO ACIDS IN THE REGION TWO HUNDRED TO TWO HUNDRED AND THIRTY MILLIMICRONS

THE ABSORPTION SPECTRA OF AMINO ACIDS IN THE REGION TWO HUNDRED TO TWO HUNDRED AND THIRTY MILLIMICRONS