A Simple Colorimetric Procedure for the Determination of Iodine Value of Vegetable Oils Using a Smartphone Camera

Abstract

A smartphone camera-based colorimetric method is developed for the determination of iodine value of vegetable oils. The small amount of Wijs reagent is employed for halogenation of the unsaturated sites of the sample. The rest of unreacted reagent is transformed into iodine, which further reacts with the starch solution to form the blue color complex. The free download smartphone application is used for measuring the blue color intensity. More than one sample can be measured by taking only one photo shot. Under the controlled illuminance, the calibration graph for measuring the iodine values of various vegetable oils is constructed from the dissolved triiodide. The detection and quantitation limits are less than 0.02 and 0.032 mM I2, respectively. This method provides a better determination result of the iodine value compared with the standard titrimetric method. This method is convenient, simple, rapid, inexpensive, and easy operation with few chemical waste products.