Spectrofluorimetric determination of iodide in urine samples without pretreatment using a miniaturized analyzer chip in a multi-syringe flow system

lodine is a nutrient and a component of the thyroid hormones essential for human growth and development [1]. Iodine status is based on the concentration of iodine excreted in urine [21 Several detection systems are used to quantify iodine in urine, namely spectrophotometric, potentiometric, and ICP-MS Most of these methods for urinary iodine concentration measurement are based on the Sandell-Kolthoff reaction [3]. The method proposed in this study consists in a fluorometric detection of the catalytic effect of the redox reaction between Ce(IV) and As(lII), using the Sandell-Kolthoff reaction, in a miniaturized chip-based flow manifold. This method was based on a previous work using an advanced three-dimensional (D) printing features as a chip for the reaction, and direct spectrofluorimetric quantification of iodide in sea water [4]. The urine samples were analyzed in the developed system without any pre-treatment, except dilution. The lack of need of a digestion or other pre-treatment of the sample and the fluorometric reaction makes this method simpler, faster and more sensitive than the classic approach of the Sandell-Kolthoff reaction method. The method was validated with samples provided by the Center for Disease Control, USA.