Abstract:

A method for the identification and determination of the polar amino components without ultraviolet activity in traditional Chinese medicines was developed. With Rhizoma Arisaematis as the object of this study, using pre-column derivatization with phenyl isothiocyanate (PITC) as the derivatization reagent, compounds were separated and identified on a C₁₈ column (100 mm×2.1 mm, 3.5 μm) by ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A total of 20 components, including 18 amino acids and 2 amine compounds were identified. Furthermore, after the optimization of the derivatization conditions, 15 amino acids were determined by high performance liquid chromatography (HPLC) on Diamonsil C₁₈ column (250 mm×4.6 mm, 5 μm), detected at 254 nm and gradiently eluted by acetonitrile and 0.05 mol/L ammonium acetate-acetic acid (pH 6.5) as the mobile phases. The results of methodological study demonstrated that the method can meet the requirements of the determination. All calibration curves expressed good linearity: Glu, Try in the range of 2-100 mg/L, Arg in the range of 6-300 mg/L, others in the range of 0.8-40 mg/L, with the correlation coefficients ≥ 0.9995. The average recovery of this method was among 95%-105% and the RSD was less than 3%. The developed method was successfully applied to quantitative determination of amino compounds in 12 batches of Rhizoma Arisaematis samples. The method is simple, sensitive, accurate, and can be used for rapid identification and determination of amino components in traditional Chinese medicines.

Key words: amino compounds, high performance liquid chromatography (HPLC), phenyl isothiocyanate (PITC), pre-column derivatization, Rhizoma Arisaematis, ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS)