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Published on: August 4, 2023
Critical comparison between modified Monier-Williams and electrochemical methods to determine sulfite in aqueous
C Montes1, J H Vélez, G Ramírez
1Departamento de Química de Los Materiales, Facultad de Química y Biología, Universidad de Santiago de Chile, Estación Central, Santiago 9170022, Chile.
Abstract:
In the present work, known concentration of sulfite aqueous solutions in the presence and absence of gallic acid was measured to corroborate the validity of modified Monier-Williams method. Free and bound-sulfite was estimated by differential pulse voltammetry. To our surprise, the modified Monier-Williams method (also known as aspiration method) showed to be very inaccurate for free-sulfite, although suitable for bound-sulfite determination. The differential pulse approach, using the standard addition method and a correction coefficient, proved to be swift, cheap, and very precise and accurate.
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