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Flow-injection potentiometric method for the routine determination of chloride: application to bread analysis
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Advisor(s)
Abstract(s)
Bread is consumed worldwide by man, thus contributing to the regular ingestion of certain inorganic species
such as chloride. It controls the blood pressure if associated to a sodium intake and may increase the incidence of stomach
ulcer. Its routine control should thus be established by means of quick and low cost procedures. This work reports a double-
channel flow injection analysis (FIA) system with a new chloride sensor for the analysis of bread. All solutions are
prepared in water and necessary ionic strength adjustments are made on-line. The body of the indicating electrode is made
from a silver needle of 0.8 mm i.d. with an external layer of silver chloride. These devices were constructed with different
lengths. Electrodes of 1.0 to 3.0 cm presented better analytical performance. The calibration curves under optimum conditions
displayed Nernstian behaviour, with average slopes of 56 mV decade-1, with sampling rates of 60 samples h-1. The
method was applied to analyze several kinds of bread, namely pão de trigo, pão integral, pão de centeio, pão de mistura,
broa de milho, pão sem sal, pão meio sal, pão-de-leite, and pão de água. The accuracy and precision of the potentiometric
method were ascertained by comparison to a spectrophotometric method of continuous segmented flow. These methods
were validated against ion-chromatography procedures.
Description
Keywords
Chloride Ion selective electrode Bread Flow-injection analysis Food
Citation
Publisher
Bentham Science Publishers Ltd.