The influence of zwitterions on the partition of biomolecules in aqueous biphasic systems


The use of hydrophilic zwitterionic compounds (ZI) to act as phase forming components of aqueous biphasic systems (ABS) has been attracting increased interest. Although previous works studied the phase behavior of ZI, there is still a lack of knowledge on the partition behavior of compounds in ZI-based ABS. This work reports a study on the influence of ZI structure for the extraction of 7 different biomolecules selected as molecular probes - 2 alkaloids (nicotine and caffeine), 2 phenolic compounds (gallic acid and vanillic acid) and 3 amino acids (L-tryptophan, L-tyrosine and L-phenylalanine). The partition and extraction efficiencies of these biomolecules were evaluated in ternary systems composed of hydrophilic ZI constituted by ammonium, imidazolium, pyridinium and piperidinium cationic and SO3- anionic groups, K2CO3 and water. The obtained results show that all the biomolecules preferentially partition to the ZI-rich phase, and the extent of their partition was closely related with the octanol-water partition coefficients of both biomolecules and ZI. It was demonstrated that the partition of biomolecules in ZI-based ABS is firstly ruled by hydrophobic/hydrophilic effects and only in some particular cases specific interactions between the biomolecule and the ZI affect their partition. Furthermore, despite the similarity between ZI and ionic liquids behavior as phase forming compounds of ABS for the extraction of biomolecules, ZI-based ABS presented a better performance in the extraction of phenolic compounds in alkaline environment.



subject category



Basaiahgari, A; Passos, H; Coutinho, JAP; Gardas, RL

our authors


This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Foundation for Science and Technology/MCTES. This work is funded by national funds through FCT - Fundacao para a Ciencia e a Tecnologia, I.P., under the Scientific Employment Stimulus - Individual Call - CEECIND/00831/2017 - under the CEEC Individual 2017. Authors would like acknowledge funding support from Indo-Portuguese Program for Cooperation in Science and Technology through DST/INT/Portugal/P-01/2017, Department of Science and Technology, India. A. Basaiahgari and R.L. Gardas would like to acknowledge IIT Madras for financial support and S.K. Yadav for synthesis of some of the ZIs.

Share this project:

Related Publications

We use cookies for marketing activities and to offer you a better experience. By clicking “Accept Cookies” you agree with our cookie policy. Read about how we use cookies by clicking "Privacy and Cookie Policy".