取经烘干并粉碎的烟叶样品0.100 0 g，加入CH₃OH-H₂O（1+1）混合液20 mL，超声提取20 min。提取液经0.45 μm滤膜过滤，滤液供高效液相色谱法分析。以Diamonsil Plus C₁₈色谱柱为固定相，并用不同比例的（A）甲醇和（B）乙酸-水（1+99）溶液的混合液按设定程序进行梯度洗脱，使样品中的绿原酸及其异构体分离。采用紫外检测器进行检测。结果表明：绿原酸的线性范围在1.01~101.22 mg·L^-1之间，其异构体（新绿原酸及隐绿原酸）则同在0.25~25.00 mg·L^-1之间，其检出限（3S/N）分别为0.013，0.025，0.028 mg·L^-1。按标准加入法进行回收试验，测得回收率在92.0%~104%之间，测定值的相对标准偏差（n=5）在1.1%~4.0%之间。

A portion of dried and powdered tobacco leaf sample (0.100 0 g) was extracted ultrasonically with 20 mL of CH₃OH-H₂O (1+1) mixture for 20 min. The extract obtained was filtered through 0.45 μm filtering membrane and the filtrate was used for HPLC analysis. Diamonsil Plus C₁₈ column was used as stationary phase and mixtures of (A) methanol and (B) CH₃COOH (1+99) solution in various proportions were used as mobile phase in the programmed gradient elution, to have chlorogenic acid and its isomers (neochlorogenic acid and crypto-chlorogenic acid) clearly separated. It was shown that linearity range for chlorogenic acid was found between 1.01-101.22 mg·L^-1, while those for its isomers (i.e., neochlorogenic acid and cryptochlorogenic acid) were found same between 0.25-25.00 mg·L^-1, and that values of detection limits (3S/N) for the 3 compounds were 0.013, 0.025, 0.028 mg·L^-1 respectively. Test for recovery was made by standard addition method, giving values of recovery in the range from 92.0% to 104%, and RSDs (n=5) in the range from 1.1% to 4.0%.