Influence of Sodium Chloride and Lithium Bromide on the Phase Behavior of a Citrate–Polyethylene Glycol 2000 Aqueous Two-Phase System

Abstract

Several studies have shown that aqueous two-phase extraction using an aqueous two-phase system (ATPS) is a promising purification technology for biomolecules (e.g., monoclonal antibodies). To beneficially influence the partitioning of the target biomolecule, a displacement agent can be added to the ATPS. Within this work, the influence of the displacement agents, sodium chloride (NaCl) and lithium bromide (LiBr), on the phase behavior of two ATPSs containing triammonium citrate and polyethylene glycol 2000 (PEG2000) and tripotassium citrate and PEG2000 was determined and compared to previous measurements for trisodium citrate−PEG2000 ATPS. Therefore, the tieline length (TLL), tie-line slope (TLS), and the size of the biphasic region of the ATPS were investigated at 298.15 K, 101.3 kPa, and pH 7. The results show that the addition of NaCl to the ATPS increases the TLL up to 47.4%, while the TLS stays constant. In contrast, the addition of LiBr causes a decrease in the TLS up to 34.5%, while the TLL remains constant. These results are in agreement with previous measurements performed for trisodium citrate−PEG2000 ATPS. Prospectively, the investigations enable a mechanistic understanding of the displacement agent effect on the phase behavior and transfer of this information to other organic salt−polymer ATPSs to improve their extraction performance.

Temperature Effect on the Phase Equilibrium of Polyethylene Glycol 2000 + Trilithium Citrate + Water Aqueous Two-Phase Systems at T = 288.15, 298.15, 308.15, and 318.15 K

“…Wessner et al used NaCl and LiBr to study the ATPS of PEG 2000 –citrate salts at room temperature and specific pHs. It was observed that the addition of NaCl and LiBr salts increased and decreased the length of the tie-lines, respectively …”

“…It was observed that the addition of NaCl and LiBr salts increased and decreased the length of the tie-lines, respectively. 34 Studies of the ATPSs of PEG + sulfate salts + water have also received extensive attention in the separation processes. Pirdashti et al measured the effect of the polymer molecular mass, pH, and temperature on the phase equilibrium of ATPSs of the ternary systems of PEG 2000 , PEG 3000 , and PEG 8000 + zinc sulfate or ammonium sulfate + water at T = 298.15, 303.15, and 308.15 K. The results proved that the two-phase region has been extended by increasing the temperature.…”

Attomolar Sensitivity in Single Biomarker Counting upon Aqueous Two-Phase Surface Enrichment

“…To test the performance of an ATPS in enhancing the mass transport of target molecules for capture on detection surfaces of bioassays, we aimed to improve the sensitivity of a SiMREPS assay of a cancer-related DNA mutation using an ATPS composed of PEG (average molecular weight, MW ∼ 3350 Da), sodium citrate, and sodium chloride to enrich the target molecules in a small volume near the assay surface during the capture step. In the PEG-citrate ATPS, a second salt, sodium chloride, is added to enhance the partitioning of nucleic acids into the salt-rich phase . First, to better understand what bulk compositions would promote the formation of an ATPS, a binodal curve with a constant mass of sodium chloride and varying PEG (MW 3350) and sodium citrate was measured using the cloud-point titration method (Supporting Information, Figure S1).…”

Liquid–Liquid Extraction of Some Biomolecules in the ATPS {Ethyl Lactate (1) + Sodium Potassium Tartrate (2) + Water (3)} at 298.15 K and 0.1 MPa

“…The replacement of traditional catalytic processes by enzymatic approaches, together with the surge in the use of biopharmaceuticals such as antioxidant-rich food supplements and monoclonal antibodies, has been increasing the demand for biomolecules and sharpening the need for more sustainable and cost-effective methodologies concerning their extraction . However, biomolecules are extremely sensitive to factors such as temperature, ionic strength, interfacial stress, and pH, so the operative conditions of extractive processes must be optimized to avoid denaturation, sterilization, and loss of activity, and to control the characteristic lability of these species …”

“…The replacement of traditional catalytic processes by enzymatic approaches, together with the surge in the use of biopharmaceuticals such as antioxidant-rich food supplements 1 and monoclonal antibodies, 2 has been increasing the demand for biomolecules and sharpening the need for more sustainable and cost-effective methodologies concerning their extraction. 3 However, biomolecules are extremely sensitive to factors such as temperature, ionic strength, interfacial stress, and pH, so the operative conditions of extractive processes must be optimized to avoid denaturation, sterilization, and loss of activity, and to control the characteristic lability of these species. 4 One of the biggest challenges for the extraction and purification of biomolecules such as amino acids, enzymes, antioxidants, hormones, antibodies, and vitamins is the preservation of their bioactivity and intrinsic value (biocompatibility), which makes processes with green solvents and mild extractive conditions almost mandatory.…”