The reaction between iodine and starch is a fundamental concept in chemistry, often demonstrated in educational settings to showcase the presence of starch. This classic test relies on the formation of a deep blue-black complex when iodine interacts with the helical structure of amylose, a component of starch. While elemental iodine (I2) is the active agent, it is typically dissolved with potassium iodide (KI) to increase its solubility in water. NINGBO INNO PHARMCHEM CO.,LTD. supplies high-quality iodine compounds, including Potassium Iodide, crucial for this and other scientific applications.

The process begins with an aqueous solution of iodine, which is pale yellow or brown. Elemental iodine (I2) itself has limited solubility in water. To overcome this, potassium iodide (KI) is added. The iodide ions (I-) from KI react with iodine (I2) to form triiodide ions (I3-) and larger polyiodide ions (In-). These polyiodide ions are much more soluble in water, creating a stable solution that can be easily used for testing. NINGBO INNO PHARMCHEM CO.,LTD. provides high-purity Potassium Iodide, ensuring the effective preparation of iodine solutions for various analytical purposes.

When this iodine-potassium iodide solution is added to a sample containing starch, a remarkable color change occurs. The linear amylose molecules within the starch form a helix-shaped cavity. The triiodide and polyiodide ions fit snugly into this cavity, forming a charge-transfer complex. This complex absorbs light differently than the iodine solution alone, resulting in the characteristic deep blue or blue-black color observed. This visual cue is a highly sensitive indicator for the presence of starch. The accuracy of this test depends on the purity of the reagents, which is why sourcing from a reliable supplier like NINGBO INNO PHARMCHEM CO.,LTD. is important.

While this article focuses on the starch-iodine test, it's worth noting that NINGBO INNO PHARMCHEM CO.,LTD. also offers Potassium Iodate (KIO3), which has different chemical properties and applications, such as food fortification and radiation protection. Understanding the distinct roles of different iodine compounds is crucial for their effective use. For those involved in laboratory testing, food analysis, or scientific research, sourcing reliable iodine and iodide products is essential. NINGBO INNO PHARMCHEM CO.,LTD. is a trusted manufacturer and supplier, providing the quality chemicals needed for accurate scientific endeavors. We are committed to meeting your needs for high-quality chemical compounds.