Photophysical Challenges and Antenna Effect Between Click Reaction-based Bodipy Derivatives Manufactured From Knorr Pyrrole

In this paper, a series of click reaction-based Bodipy derivatives have been synthesized as part of a preliminary study. Following the characterization of the four challenger molecules, the photophysical properties (absorption, emission, excitation, molar absorption coefficient, quantum yield, etc.) were examined in various organic solvents. The results showed that the energy transfer from the Bodipy cores to other moieties was calculated between 71% and 93% depending on different π-electron configurations and chromophore groups.

Phthalocyanines-based photoacoustic contrast agents for imaging and theranostics

Phthalocyanine, as an organic dye, has attracted much attention due to its high molar absorption coefficient in the near-infrared (NIR) region. It is precisely because of this advantage that phthalocyanine...

Spectral characteristics of 5-hydroxymethylfurfural as a related substance in medicinal products containing glucose

Objectives: To study 5-hydroxymethylfurfural (5-HMF) spectral characteristics aiming at their future application in analytical procedures and their validation for the determination of 5-HMF in liquid products containing glucose after sterilization. Method: Direct spectrophotometric method for the determination of 5-HMF using the molar absorption coefficient at the absorption maximum (284 nm). Results and discussion: aqueous 5-HMF solutions have strong absorption in the ultraviolet range below 310 nm and give two absorption maxima at wavelengths of 229–230 nm and 284 nm. An excellent linear relationship between absorbance and 5-HMF concentration was observed in the concentration range of 2.0–10.0 mg/l. The linear dependence passes through the origin. The molar absorption coefficients of 5-HMF were determined and found to be 3007 mol−1•L•cm−1at 229–230 nm and 16070 mol−1•L•cm−1at 284 nm. The use of the molar absorption coefficient of 5-HMF stated in the Pharmacopeia of the United States of America for determining 5-HMF in polydextrose (16830 mol−1·L·cm−1at 283 nm) gives recovery results for model solutions of reference substance of 5-HMF that are acceptable from the point of view of the requirements of the State Pharmacopeia of Ukraine for methods of quantitative determination of impurities. However, other values of the molar absorption coefficient (17000 and 22700 mol−1•L•cm−1) given in the scientific publications are unsuitable for the quantitative determination of 5-HMF as an impurity in medicinal products. Conclusion: The molar absorption coefficient (16830 mol−1•L•cm−1at 284 nm) may be used to quantify 5-HMF as an impurity in medicinal products containing glucose. For a specific medicinal product, a full validation of the analytical procedure of the 5-HMF determination is required taking into account the composition of this product.

UV-Visible Spectrophotometric Method and Validation of Organic Compounds

Absorption and emission of radiation by a compound at different wavelengths in visible and ultra violet region forms an analytical tool for identification of organic compounds. Researchers and scientists from different fields of chemistry and life sciences are constantly in search of an alternate ways to analyze the chemical reactions involving organic and inorganic compounds. The UV-Visible spectroscopic technique serves as an important and simple technique in finding concentration of molecules in a solution, identification the functional groups identification of conjugated organic compounds. The molar absorption coefficient is an intrinsic property of species, and may be treated as a fingerprint to an organic compound. This papers presents a systematic and detailed validation of organic compounds with the molar absorption coefficient in UV-visible region.

MONITORAMENTO DO CORANTE PARAROSANILINA EM AMOSTRAS BIOLÓGICAS

Pararosaniline dye (P) is a pigment which has a significant role in analysis of chemical substances and gram-positive and negative bacteria, as well as other microorganisms. Potentiometric essays of P have shown that the colorant is a weak monoprotic acid (pKa= 8,78);and the spectrophotometry allows to estimate its molar absorption coefficient as 1,48x104 mol-1 cm-1 L. The analytical curve for a determination of P has linearity between 7,36x10-6 and 7,36x10-5 mol L-1, and the methodology was application in biological samples.

π-Conjugated thiolate amplified spectrophotometry nitrite assay with improved sensitivity and accuracy

π-Conjugated thiolate amplified sensitive nitrite detection based on the π-conjugation enhanced molar absorption coefficient and the corresponding absorbance is presented.