Determination of ε-Polylysine in Foods by High Performance Liquid Chromatography with Precolumn Method of Dansyl Derivatization
1996 Volume 43 Issue 10 Pages 1105-1109
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1996 Volume 43 Issue 10 Pages 1105-1109
A high performance liquid chromatographic method has been investigated for the determination of ε-polylysine (ε-PL) known as food preservative. ε-PL was derivatized with dansyl chloride, followed by hydrolysis by 6N hydrochloric acid to produce α-dansyllysine (α-DNS-Lys). The fact that both lysine residues of proteins and free lysine molecules do not produce α-DNS-Lys in this process, suggests that ε-PL is the precursor of α-DNS-Lys. A HPLC separation was performed on a C18 reversed phase column with isocratic elution with 71mM phosphate buffer (pH 7)-methanol (7:3v/v) and fluorescence detection was at 530nm (excitation at 340nm). The method could be applied to potato salad, chinese pastry case of Gyoza and Mentsuyu. Recoveries from these samples ranged from 85% to 100% and the limit of detection was 0.05g/kg. However, when applied to fermented foods, it was required to subtract blank values in order to eliminate the risk of "positive error"
