Method development for quantification of iodine in food for special medical purposes (FSMP) after microextraction by Bi-SBA-15 based matrix solid-phase dispersion

Abstract

In this study, bismuth (Bi)-embedded SBA-15 mesoporous silica was synthesized, characterized and used as adsorbent for matrix solid phase dispersion (MSPD) of iodine in whole nutritional formula foods, subsequently determined by inductively coupled plasma mass spectrometry (ICP-MS). The experimental conditions for the MSPD were firstly investigated, utilizing a mass ratio of sample to Bi-SBA-15 at 3:3, with 200 mM [C12mim]Br as the elution solvent and a grinding time of 2 min. Meanwhile, interference studies revealed that the presence of cations (K⁺, Na⁺, Ca²⁺) could significantly decrease the analytical signal, prompting the implementation of a cation-exchange procedure. Under optimum experimental conditions, analytical performance of Bi-SBA-15 based MSPD-ICP-MS for iodine detection was evaluated in terms of limit of detection (LOD) and limit of quantification (LOQ), which was 0.03 μg/kg and 0.21 μg/kg respectively. To evaluate the accuracy and applicability of this method, a recovery study was conducted on commercial foods for special medical purposes (FSMP), with recoveries ranging from 95.5 % to 106 %. Therefore, the application of SBA-15 based matrix solid-phase dispersion would attract significant attention for separation and preconcentration of total iodine in complex food samples such as foods for special medical purposes (FSMP).