MOLYBDATE SELECTIVE ELECTRODE BASED ON HIGHER QUATERNARY AMMONIUM SALTS
Abstract
The membrane composition of molybdate-selective electrodes based on higher quaternary ammonium salts (QAS) has been optimized. It has been found that electrodes with the best analytical characteristics are based on 2,3,4-tris(dodecyloxy) benzyltrimethylammonium bromide (TM), with 4-trifluoroacetylbenzoic acid heptyl ester (HE) as the solvating additive. Their analytical characteristics, such as lower detection limits (5·10−6mol/l); selectivity coefficients to interfering chloride (2·10−3), sulfate (9·10−3), oxalate (2·10−2) and tungstate (5·10−3) ions; working pH range (7.5−8.5); and the slope of the electrode function (28 mV/pC) have been determined. Sodium molybdate aqueous solutions have been studied with FT-IR spectrometry method at various pH, and it has been shown that at pH above 7.5 hydrolysis is not significant. However, for molybdateselective electrodes it is better to use freshly prepared solutions, as it increases the reproducibility of the experimental results.
About the Authors
E. M. Rakhman’ko
Belarusian State University
Belarus
D. Sc. (Chemistr)y, Professor, Head of the Department of Analytical Chemistry
Belarus
D. Sc. (Chemistr)y, Professor, Head of the Department of Analytical Chemistry
Yu. V. Matveichuk
Mogilev State University of Food Technologies
Belarus
Ph. D. (Chemistry), Associate Professor, Chemistry Department
Belarus
Ph. D. (Chemistry), Associate Professor, Chemistry Department
A. D. Kopyrin
Belarusian State University
Belarus
Master of the Department of analytical chemistry
Belarus
Master of the Department of analytical chemistry
N. V. Potapkin
Belarusian State University
Belarus
Student of the 5th year of the department of analytical chemistry
Belarus
Student of the 5th year of the department of analytical chemistry
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