Abstract

Raman spectroscopy was used to analyze mixtures of urea and water in order to identify the influence of the urea concentration on the solution's freezing point. Our approach consisted in the analysis of urea aqueous solutions and the determination of their phase transitions at low temperatures. Hence, Raman spectra of these solutions were acquired in a −30 to 10 °C temperature range. This enabled us to build the experimental phase diagram of the urea-water binary system.

Simultaneous measurement of liquid-film thickness and solute concentration of aqueous solutions of two urea derivatives using NIR absorption

M. Lubnow, T. Dreier, C. Schulz, and T. Endres
Appl. Opt. 60(32) 10087-10093 (2021)

NIR sensor for aqueous urea solution film thickness and concentration measurement using a broadband light source

M. Lubnow, T. Dreier, and C. Schulz
Appl. Opt. 58(16) 4546-4552 (2019)

Detecting phase transitions in a CaCl₂–H₂O system at low temperatures using a fiber-optic Fresnel reflection sensor

Mani Priyadarshini, Venkata Rajanikanth Machavaram, Akella Sivaramakrishna, and Pachiyappan Arulmozhivarman
Appl. Opt. 56(11) 3229-3239 (2017)

Monitoring phase changes in supercooled aqueous solutions using an optical fiber Fresnel reflection sensor

Priyadarshini Mani, Archana Rallapalli, Venkata Rajanikanth Machavaram, and Akella Sivaramakrishna
Opt. Express 24(5) 5395-5410 (2016)

Analysis of metabolites in aqueous solutions by using laser Raman spectroscopy

Steve Y. Wang, Charles E. Hasty, Patricia A. Watson, James P. Wicksted, Rex D. Stith, and Wayne F. March
Appl. Opt. 32(6) 925-929 (1993)