Desenvolvimento de métodos analíticos para determinação de iodo em amostras de premixes e soluções expectorantes usando técnicas espectrométricas

Abstract

The excess or deficiency of iodine in human and animal organisms can cause changes in the levels of thyroid hormones, causing variations in cellular reactions, body temperature, growth, and in consequence alteration in basal metabolism. Therefore is necessary quantify the iodine content of the main sources (food and medicines) in order to have a control of the quantities consumed and product quality. For this, was verified the possibility of iodine determination in premixes and expectorants solutions by applying the technique optical emission spectrometry with inductively coupled plasma (ICP OES) and UV-VIS spectrophotometry method based on the Sandell-Kolthoff reaction. Since the premix it is a complex composition sample, was tested various extraction procedures iodine with ultrasound bath, having best response with 20.0000 g of the sample in sodium citrate aqueous solution. The syrups analysis was used dilution with water. For method development by ICP OES held central composite design in which case, studied the power, the flow of nebulizer gas and the rate of aspiration of the sample.In sequence performance characteristics tests were made, obtaining recoveries from 79.0 - 90.8 % for samples with iodate premix, 81.5 - 93.3 % for samples premix with iodide, already on syrups obtained average recoveries of 101.0 - 104.0 %. The kinetic method was used with measurements at fixed time, allowing greater agility in the acquisition of results. By this method it was possible to perform analysis of the syrups obtaining 96.3 - 98.2 % average recovery, already for premixes analyzed in this study there was interference problems in the redox reaction that governing this method, making it impossible the realization this test. Developed such methods have advantages such as techniques using simple sample preparation and the use of popular equipment for the quantification of iodine in premixes and solutions in expectorants.