Improved selectivity and detection limit of the carbonate-selective electrode.
The properties of the carbonate neutral carrier 4-( n-hexadecyl)-3-nitro-1-trifluoroacetylbenzene were compared with those of a similar carrier, without a nitro group, studied previously. In spite of differences in the Hammett constant of the carbonyl group responsible for interaction with the analyte, the analytical characteristics of both carriers, measured under the same conditions, were comparable. Special care was taken to avoid the presence of an excessive carbon dioxide level in the diffusion layer at the membrane-solution interface. The internal reference solution was prepared without carbonate components; the external solution was protected from contact with atmospheric carbon dioxide. Under such conditions the detection limit of both electrodes was extended to 10(-11 )mol L(-1), and the selectivity towards salicylate, chloride, and acetate was significantly improved.
Maj-Urawska
Magdalena
M
Department of Chemistry, University of Warsaw, Pasteura 1, 02-093, Warsaw, Poland. mmajzur@chem.uw.edu.pl
Ziemianek
Dorota
D
Mikołajczuk
Agnieszka
A
Mieczkowski
Józef
J
Lewenstam
Andrzej
A
Hulanicki
Adam
A
Sokalski
Tomasz
T