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Methorics of the Precipitation Processes. XIX. Fluorescence of Sodium Fluoresceinate, Rhodamine B and their Mixtures, as a Function of Hydrogen Ion Concentration in Water Solutions

Đ. Težak ; Laboratory of Physical Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia, Yugoslavia
B. Težak ; Laboratory of Physical Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia, Yugoslavia

Sažetak

The fluorescence of sodium fluores ceinate and rhodamine B
has been measured over a wide range of pH. The results
obtained are in full agreement with the absorption measurements
reported by previous a uthorss.13.
Precipitation maximum at about pH 3 is identical with
the minimum of fluorescence intensity for the predominant form
of fluorescein i.e. the neutral molecule. The precipitation limit at
about pH 5 is characterized by the equilibPium between the neutral
molecule and the monoanion ; the di s continued curve at pH 7
represents the equilibrium between the monoanion and the
dianion. Fluorimetric curves of divalent cation of rhodamine B r emain
practically constant over a wide rang e of pH.
In the system consisting of sodium fluoresceinate and rhodamine
B it has been shown that the phenomenon of isoelectric
precipitation takes place by »e quivalent body« formation . The
concentrational relationship between the interacting ions is
strongly influenced by the hydrogen ion concentration.

Ključne riječi

Hrčak ID:

208309

URI

https://hrcak.srce.hr/208309

Datum izdavanja:

30.9.1964.

Posjeta: 417 *