[Determination of isomerized alpha-acids in beer using solid phase extraction-high performance liquid...

Area of Science:

• Analytical Chemistry
• Food Science
• Chromatography

Context:

• Isomerized alpha-acids are key compounds influencing beer flavor and stability.
• Accurate quantification of these compounds is essential for brewing quality control.
• Existing analytical methods may lack the required sensitivity or efficiency.

Purpose:

• To develop and optimize a sensitive analytical method for quantifying four specific isomerized alpha-acids in beer.
• To couple solid phase extraction (SPE) with high performance liquid chromatography (HPLC) for efficient sample preparation and analysis.
• To establish optimal SPE conditions, including eluting solvent and pH adjustment.

Summary:

• A novel analytical method was established by optimizing solid phase extraction (SPE) parameters, utilizing acidic methanol as the eluting solvent and adjusting beer pH to 2.5.
• The optimized SPE method, coupled with HPLC, demonstrated high recoveries (90.6%-96.4%) and low relative standard deviations (<4%) for four isomerized alpha-acids.
• Achieved detection limits ranged from 0.14 mg/L to 0.53 mg/L, indicating significant sensitivity for target analytes.

Impact:

• Provides a sensitive, accurate, and reliable method for the routine analysis of isomerized alpha-acids in beer.
• Facilitates improved quality control and consistency in beer production.
• Contributes to a deeper understanding of hop compound chemistry in fermented beverages.