Fractionation and Characterization of Humic Substances in Nutritional Supplements Using Immobilized Metal Affinity...

Area of Science:

• Analytical Chemistry
• Biochemistry
• Food Science

Background:

• Humic substances are complex organic molecules found in various natural and food products.
• Accurate analysis of humic substances is crucial for understanding their biological activity and safety.
• Existing analytical methods may not fully capture the structural diversity and interactions of humic substances.

Purpose of the Study:

• To investigate the efficacy of immobilized metal affinity chromatography (IMAC) for analyzing humic substances.
• To optimize IMAC conditions for separating humic substances based on their functional groups.
• To characterize humic substances in food supplements using IMAC and complementary techniques.

Main Methods:

• Utilized an Iontosorb Salicyl sorbent functionalized with aluminum ions (Al(III)).
• Employed a stepwise gradient elution with acetate buffer solutions and sulfuric acid/sodium sulfate mixtures.
• Optimized elution parameters including Al(III) concentration, sorbent capacity, and pH.
• Validated the method using model compounds and applied it to food supplement samples.
• Further characterized IMAC fractions using size-exclusion chromatography.

Main Results:

• Established optimal IMAC conditions with 0.20 mmol Al(III) per gram of sorbent at pH 7.0.
• Demonstrated successful separation of model compounds with varying chelating properties.
• Fractionated humic substance standards and characterized humic substances in food supplements.
• Combined IMAC with size-exclusion chromatography for enhanced structural insights.

Conclusions:

• Immobilized metal affinity chromatography is a promising technique for humic substance analysis.
• IMAC facilitates the characterization of humic substance structure and metal ion interactions.
• This method offers a valuable tool for quality control and research in food supplements and related fields.