Table 1. Overview and short description of (electronic) rapid test kits used in this validation.
| Device name | Manufacturer | Method principle | Description of test kit contents |
|---|---|---|---|
| iCheck iodine(‘iCheck’) | BioAnalyt LLC, Potsdam, Germany (www.bioanalyt.com) | Reduction of iodate to iodine by potassium iodide, followed by the formation of penta-iodide anions that inside the helical β-amylose chain of starch form a blue color that is linear with the iodine concentration. Colorimetric quantification of the concentration using photospectrometry. | Device, scale and power plug come with the device kit; activation solution, reagent vials, syringes and needles come with the reagent kits. Only purified water and plastic flasks required. |
| ID-ERTK (‘ID-ERTK’) | Innovative Design, Chennai, India (currently, no website available) | Device comes with power plug, scale, quartz cuvette, scale and some other lab hardware.Reagent solutions need to be prepared by the user. | |
| I-Reader(‘I-Reader’) | Mahidol University, Institute for Innovative Learning, Mahidol, Thailand (http://www.il.mahidol.ac.th/eng/index.php/2012-09-11-07-32-25/test-kits/31-new-quantitative-method-for-determination-of-iodate-in-salt.html) | Device comes with pyrex tubes and tube holder, disposable pipettes and small dosage spoons (to measure the salt volumetrically rather than by weight), and a basic reagent stock (two bottles, sufficient for approx. 330 analyses). Scale not included. | |
| saltPAD(‘saltPAD’) | University of Notre Dame, Notre Dame, Indiana, USA (http://padproject.nd.edu/) | Iodate is reduced to triiodide using potassium iodide. Thiosulfate is used to titrate a predetermined amount of triiodide. Excess triiodide reacts with starch to form a blue color that can be calibrated for visual or computerized image analysis. | This device is not yet commercially available, beta-testing version was used for this evaluation. Besides the testing cards that were delivered by the developer, a light box had to be constructed to take pictures for automated analysis, as well as a standard calibration series had to be prepared for calibration of the software to the specific light conditions. |
| WYD iodine checker (‘WYD’) | Salt Research Institute of China, National Salt Industry Corporation, Tianjin, PR China (website in Chinese only) | Same as iCheck, ID-ERTK and I-Reader. | Test kit comes with device and power plug, some lab hardware and a manual. Scale not included. Reagent solutions need to be prepared by the user. |
| MBI-RTK*(‘RTK’) | MBI Kits International, Chennai, India (www.mbikits.com) | Same principle, but no ‘quantitative’ instrumentation. | Comes with check solution, re-check solution and color-scale. No other material required. |
*This test is semi-quantitative or qualitative only and was only included for the analysis of the blinded samples to be able to calculate the kappa-statistics.