It is shown that, the basic natural frequency will decrease and the internal force response factor will increase if the random geometric imperfections are taken into consideration.

Objectives: to develop the HPLC-ELSD method to detect the different amino acids and analyze the response factors of different constituents detected by ELSD.

In cases where the response factors are not close, this practice may still be acceptable, provided a correction factor is applied or the impurities are, in fact, being overestimated.