Abstract
The partitioning behavior of the pertechnetate anion was studied in aqueous biphasic systems (ABS) formed from (NH 4) 2SO 4 and four types of polymers – poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), Pluronic (a PEG/PPG block copolymer), and polyvinylpyrrolidone (PVP). Phase diagrams are reported for five (NH 4) 2SO 4-polymer ABS systems including the polymers PEG-2000, PEG-3400, PEG-12 000, Pluronic-L64 (average molecular mass ≈ 2900), and PVP-K15 (average M r≈10 000). Distribution ratios for the TcO 4 − anion in each of these ABS were investigated as a function of increasing salt concentration. In addition, the water-insoluble polymer PPG-2000 was studied. Pertechnetate partitions nearly quantitatively to the polymer-rich phase in each ABS, however, distribution ratios of near one were found for the PPG system. The relative ordering of the distribution ratios is PPG⪡PVP⪡-2000<PEG-3400≈PEG-12 000<Pluronic-L64. For the three PEG-ABS systems, distribution ratios of the sulfate of the sulfate anion decrease in the order PEG-2000>PEG-3400>PEG-12 000, exhibiting the expected increase in phase incompatibility with increasing polymer M r. Investigation of pertechnetate partitioning in two additional ABS based on K 3PO 4 and NaOH with Pluronic-L64 revealed trends similar to those reported for PEG-2000; the distribution ratio ( D) values increase in the order NaOH<(NH 4) 2SO 4<K 3PO 4. Despite the higher distribution ratios from Pluronic-L64 at lower concentrations than found for PEG, the limited useable range of salt concentrations available may limit the practical utilization of this polymer in ABS separations.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: Journal of Chromatography B: Biomedical Sciences and Applications
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.