Iodimetry: A Sensitive Technique for Measuring Iodine Levels

Iodimetry is a technique used to measure the amount of iodine in a solution. It is based on the reaction between iodine and a reagent, usually sodium thiosulfate, which produces a colored complex that can be measured spectrophotometrically. The amount of iodine present in the solution is directly proportional to the absorbance of the colored complex.

Iodimetry is commonly used to determine the amount of iodine in biological fluids, such as thyroid hormones, and in pharmaceuticals, such as iodinated contrast agents. It is also used to measure the amount of iodine in water and food samples.

The principle of iodimetry is based on the reaction between iodine and sodium thiosulfate, which produces a colored complex that can be measured spectrophotometrically. The reaction is as follows:

I2 + 2Na2S2O3 → 2NaI + 2Na2S4O6

The colored complex, Na2S4O6, has a maximum absorbance at around 470 nm, which can be measured using a spectrophotometer. The amount of iodine present in the solution is directly proportional to the absorbance of the colored complex.

Iodimetry is a simple and sensitive method for measuring iodine levels, and it has been widely used in various fields, including clinical chemistry, pharmaceutical analysis, and environmental monitoring. However, it may not be suitable for all types of samples, and other methods, such as chromatography or immunoassays, may be more appropriate for certain applications.