一点法与工作曲线法两种外标法选择依据的探讨

Discussion on superseding working curve method using one-point external standard method in quantitative analysis

目的 :根据试验测定的标准直线 y=kx+b,如何根据直线方程中系数 k、b及进样量选择使用外标一点法还是用工作曲线法进行测定。方法 :使用数学推导出偏差计算公式并通过测定芍药苷的量进行验证。结果 :根据数学推导得因使用不同外标法而引起的偏差公式为 ε=bkx0 +b× (1- x0x1) (x0 ,x1 分别为对照品及样品进样量 )。结论 :高效液相色谱法 (气相色谱法 ) ,允许使用不同外标法引起偏差为 1% ,当标准直线方程中系数符合 bkx0 +b ≤ 3.5 %时 ,或薄层色谱扫描法 ,允许使用不同外标法引起偏差为 3% ,当标准直线方程中系数符合 bkx0 +b ≤ 10 .5 %时 ,样品进样量至少为对照品进样量的 80 %～ 140 %范围内 。

OBJECTIVE: to discuss on superseding working curve method using one point external standard method in quantitative analysis. METHOD: The equation to calculate error caused by different external standard methods was derived and validated by experiment. RESULT: the error equation is :ε=bkx 0+b×(1-x 0x 1). CONCLUSION: if ε=1% and bkx 0+b≤3.5% for the HPLC or GC, ε=3% and bkx 0+b≤10.5% for the TLCS, and the amount of test sample (x 1) is at least 80~140% of the amount of external standard (x 0), one point external standard method can supersede by working curve method in quantitative analysis.