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Critical evaluation of buffering solutions for pKa determination by capillary electrophoresis

✍ Scribed by Elisabet Fuguet; Mario Reta; Carme Gibert; Martí Rosés; Elisabeth Bosch; Clara Ràfols

Publisher
John Wiley and Sons
Year
2008
Tongue
English
Weight
630 KB
Volume
29
Category
Article
ISSN
0173-0835

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✦ Synopsis

Abstract

The performance of the most common and also some other less common CE buffers has been tested for the p__K__~a~ determination of several types of compounds (pyridine, amines, and phenols). The selected buffers cover a pH ranging from 3.7 to 11.8. Whereas some buffers, like acetic acid/acetate, BisTrisH^+^/BisTris, TrisH^+^/Tris, CHES/CHES^−^, and CAPS/CAPS^−^ can be used with all type of analytes, others like ammonium/ammonia, butylammonium/butylammonia, ethylammonium/ethylammonia, diethylammonium/diethylammonia, and hydrogenphosphate/phosphate are not recommended because they interact with a wide range of compounds. The rest of the tested buffers (dihydrogenphosphate/hydrogenphosphate, MES/MES^−^, HEPES/HEPES^−^, and boric acid/borate) can show specific interactions depending on the nature of the analytes, and their use in some applications should be restricted.

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