OBJECTIVE: To establish the reversed phase high-performance liquid chromatography method for the determination of chlorogenic acid and catalpol in modified Simiao Yong’an decoction. METHODS: The chromatographic column was Merck Purospher? STARLP RP-18 endcapped column（250 mm×4.6 mm

5 μm）

the flow rate was 1.0 mL/min

the column temperature was 35 ℃.（1） The chromatographic conditions of chlorogenic acid were acetonitrile-0.4% phosphoric acid（V∶ V=11∶ 89） as mobile phase

and the detection wavelength was 327 nm.（2） The chromatographic conditions of catalpol were as follows

mobile phase A was acetonitrile

mobile phase B was 0.1% phosphoric acid

gradient elution（from 0 to 15 min

0.8%A; from 15 to 60 min

2%A）

and the detection wavelength was 210 nm. RESULTS: Chlorogenic acid showed a good linear relationship in the ranges of 4.420 μg/mL to 442.0 μg/mL（r=0.999 8）

the average recovery was 99.38%（RSD=1.26%）. Catalpol showed a good linear relationship in the range of 9.760 μg/mL to 488.0 μg/mL（r=0.999 9）

the average recovery was 99.34%（RSD=1.43%）. The minimum detection limits of chlorogenic acid and catalpol were 0.40 ng and 0.82 ng

and the quantitative limits were 1.20 ng and 2.44 ng

respectively. The precision RSD were 0.71%（n=6） and 0.45%（n=6）

respectively. CONCLUSIONS: The method has the advantages of simple operation

good separation effect

repeatability and high accuracy

which can be used for the quality evaluation of the extract of modified Simiao Yong’an decoction.