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Advisor(s)
Abstract(s)
In the initial stage of this work, two potentiometric methods were used to determine the salt (sodium
chloride) content in bread and dough samples from several cities in the north of Portugal. A reference
method (potentiometric precipitation titration) and a newly developed ion-selective chloride electrode
(ISE) were applied. Both methods determine the sodium chloride content through the quantification of
chloride. To evaluate the accuracy of the ISE, bread and respective dough samples were analyzed by both
methods. Statistical analysis (0.05 significance level) indicated that the results of these methods did not
differ significantly. Therefore the ISE is an adequate alternative for the determination of chloride in the
analyzed samples. To compare the results of these chloride-based methods with a sodium-based
method, sodium was quantified in the same samples by a reference method (atomic absorption
spectrometry). Significant differences between the results were verified. In several cases the sodium
chloride content exceeded the legal limit when the chloride-based methods were used, but when the
sodium-based method was applied this was not the case. This could lead to the erroneous application of
fines and therefore the authorities should supply additional information regarding the analytical
procedure for this particular control.
Description
Keywords
Potentiometry Ion-selective electrode Atomic absorption spectrometry Salt Sodium chloride Food legislation Bread Food analysis Food composition
Citation
Publisher
Elsevier