Iodine content determination in dried talli of laminaria by galvanostatic coulometry

Abstract

Dried seaweeds are well-known food source with rich iodine content that can be used for the prevention of iodine deficiency disorders (IDD) independently as well as functional ingredients in dietary foods. Considering the above, analysis of total iodine content in seaweeds is an important pursuit. Materials and methods. The total content of iodine in samples of dried thalli laminaria, known as a commercial product Kombu, was determined by galvanostatic coulometry with potentiometric indication of the end point of the titration in aqueous solution obtained by mineralization samples. Results and discussion. Contained in the samples iodinated compounds such as organic and inorganic nature, by a dry alkaline mineralization were transferred to the aqueous solution in the form of iodides. The procedure was carried out at the optimal temperature conditions within 420-480ºC which provides maximum yield. Standard aqueous solutions of sodium iodide in the concentration range of 15-300 mg / 100 g of solution used for the analytical method validation of determining the concentration of iodide by galvanostatic coulometry with electrogenerated bromine. These key characteristics of validation procedure, such as the specificity, linearity, range of analytical procedure, accuracy and precision, led to the conclusion about the possibility of using galvanostatic coulometry for the determination of total iodide in the solutions. Was confirmed that the electrogenerated bromine reacts with iodide in the ratio 1:1. The iodine content surveyed for four series of kombu was 394, 476, 587 and 743 mg/100 g dry algae, respectively. Conclusions. Using the coulometric method for solving the problems of quantitative determination of iodine content in popular seaweed products as Kombu and others is suggested.