A new method for quantifying iodine in a starch-iodine matrix

Area of Science:

• Analytical Chemistry
• Food Science
• Materials Science

Background:

• Accurate quantification of iodine in starch is crucial for food fortification and quality control.
• Existing methods may lack sensitivity or require complex sample preparation for intact starch granules.

Purpose of the Study:

• To develop and validate a rapid and sensitive method for quantifying iodine directly within intact starch granules.
• To establish a reliable analytical technique for diverse starch matrices and iodine concentrations.

Main Methods:

• Sample preparation involved reducing iodine species to iodide ions using sodium borohydride (NaBH(4)).
• Quantitative derivatization of iodide to ethyl iodide (EtI) was performed using triethyloxonium tetrafluoroborate (Et(3)O(+)BF4-) in dichloromethane (CH(2)Cl(2)).
• Identification and quantification utilized gas chromatography-mass spectrometry (GC-MS) and routine analysis employed gas chromatography with a flame ionization detector (GC-FID).

Main Results:

• The method achieved low detection limits, as low as 0.2% (w/w) iodine in starch.
• High regression coefficients (R(2)>0.96) were observed for standards across different iodine:potassium iodide ratios and seven starch matrices.
• The developed gas chromatography method demonstrated high accuracy and reproducibility.

Conclusions:

• The described gas chromatography method provides a rapid, sensitive, and reliable approach for quantifying iodine in intact starch granules.
• This technique is suitable for routine analysis and applicable to various starch types and iodine binding conditions.
• The method offers significant advantages for quality control and research in iodine-fortified food products and materials.