Comparison of Analysis of Organic Acids using RSpak KC-811 with 4 Kinds of Detectors was shown. When analyzing organic acid satndards , 4 kinds of detectors are usable. However, when analyzing actual sample, we recommend to use the post-column method which allows high-selective analysis of organic acids. For example, soy sauce is a complicated mixture of organic acids, amino acids, saccharides, NaCl, ions and organic compounds. With UV detector (210 nm), too many organic substances, organic compounds and organic acids are detected. With a conductivity detector, organic acids cannot be quantified satisfactory, as the NaCl peak is appearing at around 10 minutes is large. Also it is difficult to quantify organic acids with an RI detector, as almost all the components including saccharides are detected.



Sample : Soy sauce
1. Citric acid
2. Pyruvic acid
3. Malic acid
4. Succinic acid
5. Lactic acid
6. Formic acid
7. Acetic acid
8. Pyroglutamic acid

Columns      : Shodex RSpak KC-G 6B (6.0 mm I.D. x 50 mm) + KC-811 (8.0 mm I.D. x 300 mm) x 2
Eluent       : 3 mM HClO4 aq.
Flow rate    : 1.0 mL/min
Column temp. : 50 °C