Analysis of Organic Acids in Soy Sauces (KC-811)

Soy sauces were analyzed using RSpak KC-811, a column for organic acids analysis. Compared to a dark soy sauce, a light soy sauce contains less total organic acids, especially lactic acid (peak No.6). On the other hand, a soy sauce mixed with amino acid solution was observed to contain a large amount of formic acid (peak No.7) and levulinic acid (peak No.9), which are thought to be derived from the amino acid solution.

Sample: 20 µL
3-fold diluted Soy sauce

  1. 1.Phosphoric acid, etc.
  2. 2.Citric acid
  3. 3.Pyruvic acid
  4. 4.Malic acid
  5. 5.Succinic acid
  6. 6.Lactic acid
  7. 7.Formic acid
  8. 8.Acetic acid
  9. 9.Levulinic acid
  10. 10.Pyroglutamic acid
Shodex RSpak KC-G 8B (8.0 mm I.D. x 50 mm) + KC-811 (8.0 mm I.D. x 300 mm) x 2
4.8 mM HClO4 aq.
Flow rate
(Eluent); 1.0 mL/min, (Reagent) ; 1.1 mL/min
VIS (430 nm) *Post column method
Column temp.
50 ℃

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