Modified asynchronous orthogonal sample design scheme @ Job’s method to determine the stoichiometric ratio in the molecular association system

Abstract The determination of the stoichiometric ratio in the molecular association system is of great signification. The asynchronous orthogonal sample design scheme @ Job’s (AOSD@Job’s) method, which was developed in our previous work, had a considerable advantage over the commonly-used Job’s method. However, the AOSD@Job’s method might give incorrect results due to the severe interference of the noise from the spectral measurements. In this paper, a modified AOSD@Job’s (MAOSD@Job’s) method was proposed by introducing the modified reference spectrum into the AOSD@Job’s method. Firstly, mathematical analysis suggested that the MAOSD@Job’s method might be more robust to noise compared with the AOSD@Job’s method. Then, the results of computer simulation showed that the stoichiometric ratios obtained from the MAOSD@Job’s method were all consistent with the set values under the disturbance of noise. However, AOSD@Job’s method produced incorrect stoichiometric ratios in the computer simulation experiments due to the interference of noise. Lastly, the MAOSD@Job’s method was successfully applied on two real chemical systems.