Monitoring dediazoniation product formation by high-performance liquid chromatography after derivatization.
J Chromatogr A
; 989(2): 221-9, 2003 Mar 14.
Article
em En
| MEDLINE
| ID: mdl-12650254
ABSTRACT
A derivatization protocol that exploits the rapid reaction between arenediazonium ions and a suitable coupling agent followed by high-performance liquid chromatography analyses of the reaction mixture was employed to determine the product distribution, the rate constants for product formation and the association constant of 4-nitrobenzenediazonium, PNBD, ion with beta-cyclodextrin, beta-CD. The derivatization of PNBD with the coupling agent leads to the formation of a stable azo dye that prevents by-side reactions of PNBD with the solvents of the mobile phase, including water, or the metallic parts of the chromatographic system that would eventually lead to erroneous identification and quantification of dediazoniation products. The results show that in the presence of beta-CD, nitrobenzene is formed at the expense of 4-nitrophenol, which is the major product in its absence. The observed rate constants for the interaction between PNBD and beta-CD increase upon increasing [beta-CD] showing a saturation profile indicative of the formation of an inclusion complex between PNBD and beta-CD. By fitting the experimental data to a simplified Lineaweaver-Burk equation, the corresponding association constant and the maximum acceleration rate of beta-CD towards PNBD were estimated. The protocol is applicable under a variety of experimental conditions provided that the rate of the coupling reaction is much faster than that of dediazoniation.
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Base de dados:
MEDLINE
Assunto principal:
Cromatografia Líquida de Alta Pressão
/
Beta-Ciclodextrinas
/
Compostos de Diazônio
Idioma:
En
Ano de publicação:
2003
Tipo de documento:
Article