Fig. 4 shows the comparative efficiency of the eluents. It can be seen
that 15% HCl resulted the best option to reach a complete elution of the
analyte in one step. For L-cysteine, tartaric acid and citric acid, a complete
recovery of Sb(III) was reached after two or three elution cycles.
In addition, citric acid was disregarded as eluent because of the bad reproducibility
of Sb signal (%RSD N 10) aswell as the formationof foamin
the gas–liquid separator. On the basis of the study described above,
1mMphthalate buffer at pH=6 (reactionmedia) and 15% HCl (eluent)
were the selected conditions for further work.