Citric acid is a functional food component which is effective in reducing fatigue in daily life and after exercise when regularly taken. Citric acid in a commercial functional beverage was analyzed using an organic-acids-analysis column, RSpak KC-811. A good linear calibration was obtained for the concentration range of 1 to 1,000 mg/L. Generally, a highly selective post-column method is required for the analysis of organic acids in foods, which contain many components such as food. However, for the analysis of functional beverages, a UV detector was effective for detecting the target, citric acid, without the influence of other components. The functional beverage can be analyzed after a simple dilution.

Sample preparation

1. (1)Dilute a commercial citric acid-containing functional beverage 50-fold with water.
2. (2)Filer using a 0.45-µm membrane filter and use it as an injection sample.

Sample: 5 µL
Standard solution

1. 1.Citric acid  1000 mg/L

Commercial functional drink

1. 1.Citric acid
2. 2.Acetic acid