HPCPC separation of proteins using polyethylene glycol-potassium phosphate aqueous two-phase

A new aqueous biphasic system containing polypropylene glycol and a water-miscible ionic liquid

In this work, we proposed a novel aqueous biphasic system (ABS) composed of polypropylene glycol P400 (PPG P400) and hydrophilic ionic liquids (IL), 1-alkyl-3-methylimidazolium bromide (alkyl = ethyl or butyl), forming an upper polymer-rich phase and a lower IL-rich phase at ambient temperature. This new ABS can present interesting characteristics shared by ILs and polymers such as low volatility, good solvation ability, tunable physical properties, and high design capacity for achieving task-specific phase components to enhance the partitioning of target species. Ternary phase diagram of the novel ABS formed by PPG 400 and [C(2) mim]Br in water was measured at T = 298.15 K. Factors affecting the binodal curves such as the cation side alkyl chain length and the temperature were also evaluated. The results were successfully interpreted in terms of the kosmotropic/chaotropic nature of ILs. Furthermore, the phase behavior of the PPG-[C(2) mim]Br ABS is described by the NRTL model. Finally, the extraction potential of the proposed ABS was evaluated through its application to the extraction of the essential amino acids such as L-tryptophan and L-tyrosine. The partition coefficients here obtained demonstrated the fine potential of the proposed ABS for biomolecules separation.

Separation Strategies for Processing of Dilute Liquid Streams

Processing of dilute liquid streams in the industries like food, agro-, biotechnology, pharmaceuticals, environment, and so forth needs special strategy for the separation and purification of the desired product and for environment friendly disposal of the waste stream. The separation strategy adopted to achieve the goal is extremely important from economic as well as from environmental point of view. In the present paper we have reviewed the various aspects of some selected universal separation strategies such as adsorption, membrane separation, electrophoresis, chromatographic separation, and electroosmosis that are exercised for processing of dilute liquid streams.

Extraction of trace acetylspiramycin in real aqueous environments using aqueous two-phase system of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate and phosphate

The partitioning of acetylspiramycin was carried out in an aqueous two-phase system (ATPS) formed by a hydrophilic ionic liquid (1-butyl-3-methylimidazolium tetrafluoraborate, [Bmim]BF4) and NaH2PO4. This ATPS is a simple, non-toxic and effective sample pretreatment technique, which was developed for the simultaneous separation, enrichment and rapid analysis of acetylspiramycin coupled with molecular fluorescence spectrophotometry. Analysis of the liquid-liquid equilibrium of [Bmim]BF4-salt ATPS demonstrated that the salting-out ability of different salts may be related to the Gibbs energy of hydration of the ions. The effects of types of salts, concentration of NaH2PO4, and temperature were analysed. Under optimum conditions, the average extraction efficiency and partition coefficient were 90.14% and 91.1, respectively. Thermodynamic functions provide some information about the molecular mechanism involved in acetylspiramycin transfer to the top phase, suggesting an important acetylspiramycin-[Bmim]BF4 interaction. The method yielded a linear range in the concentration from 1.0 to 10.0 µg mL−1 of acetylspiramycin, and the limit of detection was 0.02 µg mL−1. This method could be successfully applied for the analysis of acetylspiramycin in lake water, river water and groundwater. The proposed extraction technique appears to be suitable as a first step for the separation of macrolide antibiotics from real aqueous environments.

The effect of KSCN on the partition of proteins in polyethylene glycol/(NH4)2SO4 aqueous two-phase system

The effect of potassium thiocyanate on the partitioning of lysozyme and BSA in polyethylene glycol 2000/ammonium sulfate aqueous two-phase system has been investigated. As a result of the addition of potassium thiocyanate to the PEG/ammonium sulfate system, the PEG/mixed salts aqueous two-phase system was formed. It was found that the potassium thiocyanate could alter the pH difference between the two phases, and, thus, influence the partition coefficients of the differently charged proteins. The relationship between partition coefficient of the proteins and pH difference between two phases has been discussed. It was proposed that the pH difference between two phases could be employed as the measurement of electrostatic driving force for the partitioning of charged proteins in polyethylene 2000/ammonium sulfate aqueous two-phase system.