Aggregation of Methylene Blue in Frozen Aqueous Solutions Studied by Absorption Spectroscopy

HEGER, Dominik, Jaromír JIRKOVSKÝ and Petr KLÁN. Aggregation of Methylene Blue in Frozen Aqueous Solutions Studied by Absorption Spectroscopy. Journal of Physical Chemistry A. USA: The American Chemical Society, 2005, vol. 109, No 30, p. 6702-6709. ISSN 1089-5639.

Basic information

• Original name: Aggregation of Methylene Blue in Frozen Aqueous Solutions Studied by Absorption Spectroscopy
• Name in Czech: Aggregation of Methylene Blue in Frozen Aqueous Solutions Studied by Absorption Spectroscopy
• Authors: HEGER, Dominik (203 Czech Republic), Jaromír JIRKOVSKÝ (203 Czech Republic) and Petr KLÁN (203 Czech Republic, guarantor).
• Edition: Journal of Physical Chemistry A, USA, The American Chemical Society, 2005, 1089-5639.

Other information

• Original language: English
• Type of outcome: Article in a journal
• Field of Study: 10403 Physical chemistry
• Country of publisher: United States of America
• Confidentiality degree: is not subject to a state or trade secret
• Impact factor: Impact factor: 2.898
• RIV identification code: RIV/00216224:14310/05:00012597
• Organization unit: Faculty of Science
• UT WoS: 000230897000012
• Keywords in English: photochemistry; aggregation; methylene blue
• Tags: aggregation, methylene blue, Photochemistry
• Tags: International impact

Abstract

The paper presents a qualitative as well as quantitative spectroscopic study of methylene blue (MB) aggregation that occurs upon freezing the aqueous solutions over a wide concentration range. The Gaussian curve analysis and the multivariate curve resolution-alternating least squares method were used to determine the number and concentration of chemical species responsible for the overlaying absorption visible spectra measured. The results show the extent of aggregation for the concentrations above 10(-7) mol L(-1), being dependent on the freezing rate and the initial concentration. While the local concentration of MB at the grain boundaries of polycrystalline ice increased by approximately 3 orders of magnitude upon fast freezing at 77 K compared to the liquid phase, the concentration raised at least by 6 orders of magnitude upon slow freezing at 243 K. Since enhancement of the local concentration of solutes plays an important role in (photo)chemical transformations in solid aqueous media, this work helps to understand how the initial conditions control the course of the process. The results are relevant in other interdisciplinary fields, such as environmental chemistry, cosmochemistry, or geochemistry.

Abstract (in Czech)

The paper presents a qualitative as well as quantitative spectroscopic study of methylene blue (MB) aggregation that occurs upon freezing the aqueous solutions over a wide concentration range. The Gaussian curve analysis and the multivariate curve resolution-alternating least squares method were used to determine the number and concentration of chemical species responsible for the overlaying absorption visible spectra measured. The results show the extent of aggregation for the concentrations above 10(-7) mol L(-1), being dependent on the freezing rate and the initial concentration. While the local concentration of MB at the grain boundaries of polycrystalline ice increased by approximately 3 orders of magnitude upon fast freezing at 77 K compared to the liquid phase, the concentration raised at least by 6 orders of magnitude upon slow freezing at 243 K. Since enhancement of the local concentration of solutes plays an important role in (photo)chemical transformations in solid aqueous media, this work helps to understand how the initial conditions control the course of the process. The results are relevant in other interdisciplinary fields, such as environmental chemistry, cosmochemistry, or geochemistry.

Links

• GA205/05/0819, research and development project: Name: Environmentální důsledky fotochemických transformací v ledu a sněhu

Investor: Czech Science Foundation, Enviromental consequences of photochemical processes in ice and snow

• MSM0021622412, plan (intention): Name: Interakce mezi chemickými látkami, prostředím a biologickými systémy a jejich důsledky na globální, regionální a lokální úrovni (INCHEMBIOL) (Acronym: INCHEMBIOL)

Investor: Ministry of Education, Youth and Sports of the CR, Interactions among the chemicals, environment and biological systems and their consequences on the global, regional and local scales (INCHEMBIOL)