Solute clusters in aqueous citric acid solutions

✍ Scribed by Kazunari Ohgaki; Yoshihiro Makihara; Makoto Morishita; Masahiro Ueda; Norio Hirokawa

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 1022 KB
• Volume: 46
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(91)85029-w

✦ Synopsis

Densities of aqueous citric acid monohydrate solutions are examined at three different concentrations. Two supersaturated solutions exhibit density gradients in a vertical column, but a saturated solution does not. The dksity gradients can be expressed satisfactorily by use of a theoretical model based on the Brownian diffusion equation for solute clusters under gravity. Electron microscopy also strongly suggests the existence of solute clusters in supersaturated solutions. The cluster size is estimated to be about 16 nm in diameter. Ultraviolet-ray scattering suggests a possible secondary structure of cluster aggregations.