Pre-column Derivatization RP-HPLC Determination of Amino Acids in Asparagi Radix before and after Heating Process

A pre-column derivatization RP-HPLC assay was established for the simultaneous determination of 12 kinds of amino acids in Asparagi Radix before and after heating process. PITC was used as pre-column derivatization reagent. The obtained amino acid derivatives were separated on C18 column (250 × 4.6 mm i.d., 5 μm) by using gradient elution with 0.1 mol/L pH6.5 acetate buffer solution-acetonitrile (93:7,v/v) as mobile phase A and acetonitrile-water (4:1,v/v) as mobile phase B. 12 kinds of amino acids could be detected at 254 nm in 40 min with a flow rate of 0.9 mL/min. Linear range was between 0.5-500 μg/mL and average recovery was between 75.4% -100.1%. Experimental results showed that the amino acid content in Asparagi Radix was decreased after heating process.