Molecular Weight Cut-Off Determination for Polysulfone Membranes

Importance of the Topic

Polysulfone membranes play a critical role in applications such as haemodialysis wastewater recovery and food and beverage processing offering high flow rates at low pressures and tunable pore sizes.

Objectives and Study Overview

This study aims to determine the molecular weight cut off MWCO of polysulfone membranes by combining filtration experiments with GPC SEC analysis of dextran samples covering the full pore size distribution.

Applied Methodology and Instrumentation

Filtration of a broad MW dextran stock solution through membrane cartridges was followed by analysis of the stock solution filtrates and optional retentates on a GPC SEC system equipped with a refractive index detector.

• Isocratic pump mobile phase water with 0.1 M sodium chloride flow rate 1 mL per minute
• Autosampler injection volume 100 μL
• Columns Agilent SUPREMA precolumn and separation columns 30 Å and two 1000 Å 5 μm
• Temperature 23 °C sample concentration 2 to 3 mg per mL
• Calibration with dextran calibration kit
• Refractive index detector WinGPC software for data evaluation

Main Results and Discussion

Overlaid GPC SEC RI traces revealed clear differences between membranes A and B with reduced passage of high molecular weight species and a defective membrane C showing no discrimination across the dextran distribution.
Sieve curves were calculated from the ratio of filtrate to stock signal and MWCO values were extracted at defined retention percentages demonstrating membrane selectivity and pore size distribution.

Benefits and Practical Applications of the Method

GPC SEC based MWCO determination provides a rapid robust and cost efficient approach to membrane characterization enabling quality control compliance with regulated laboratory standards and minimizing sample handling steps.

Future Trends and Potential Applications

• Development of advanced membrane materials with tailored pore architectures
• Integration of multi detector GPC SEC setups for improved accuracy
• Use of real time inline monitoring and automation for manufacturing control
• Implementation of AI driven data analysis for predictive membrane performance

Conclusion

The combination of filtration experiments and GPC SEC analysis with refractive index detection offers a reliable tool for determining the molecular weight cut off of polysulfone membranes enabling detailed characterization of pore size distribution and membrane selectivity.

Reference

• Kilz P Viktorin M Quality Control and Advanced Characterization of Membranes LC GC Europe 2007 20 4 224 230
• Kilz P Characterization of Membranes by SEC Polymer Science and Materials Engineering 1997 77 56