Development and evaluation of a simple kit for iodated salt

Abstract

Regular monitoring of salt at consumption level is very important for the control of iodine deficiency disorders through iodine fortified salt. A simple and inexpensive single solution field kit, specific to iodate, was developed for this purpose. The kit showed reproducible results for the target range of 0–50 parts per million (ppm) of iodine. The minimum detectable iodine level was 1.02 ± 0.012 ppm (mean ± 2SD, 95 % CI). The shelf-life of the kit was more than 2 years. The cost of one kit that monitors 100–150 salt samples was 7 cents (0.07$). Instructions for preparing the field kit are presented. The performance of the kit was evaluated against laboratory iodometric titration. About 2,32,000 salt samples in the field and 1,224 samples in the laboratory were tested. Excellent agreement was observed between the results of the kit and iodometric titration (R2 = 0.999). The intake of adequately iodated salt determined by the kit and iodometric titration was 43 % and 44 % respectively. There were no false positive results when bromate or bleaching powder was substituted in place of iodate in salt.