In 1964 , John C. Moore published a monograph on gel permeation chromatography ( GPC ) that has changed the way scientists study polymers and macromolecules. After nearly half a century, GPC 's theory, experimental technology and instrument performance have developed by leaps and bounds. GPC has also been widely used in various fields such as industry, agriculture, medicine, health, and national defense. In recent years, with the rapid development of biomedicine, GPC has become an indispensable tool for medical research and development .
Humans have a long history of using polymer materials, and they are ubiquitous in all aspects of life. As the demand for materials in human society continues to expand, polymer materials develop rapidly and play an important role in various fields of the national economy, especially in the field of biomedicine. Molecular materials are even more irreplaceable. If researchers want to develop polymer materials with unique functions, information such as molecular weight and molecular structure is a key factor.
Before the emergence of GPC technology, researchers mostly used the viscosity method, osmotic pressure method and ultracentrifugation to measure the molecular weight of high molecular polymers. However, these methods are not only time-consuming, but also cumbersome to operate, and the amount of solvent consumed is also large. With the advent and maturity of GPC technology, researchers can obtain the relative molecular weight and molecular structure of polymers without having to spend too much cost and simple operation, thus becoming biomedical polymers and synthetic polymer materials. The development provides strong support.
Under the background of the vigorous development of biomedicine, Shanghai Jiaotong University (hereinafter referred to as Jiaotong University), a well-known domestic university, started research on biomedical polymers and synthetic polymers in the 1980s. In the early stage of the research, the traditional GPC system was used to detect macromolecules and synthetic polymers. The system only contains differential RI or UV UV detectors, which have good precision and reproducibility, and can help researchers obtain relative molecular weight. information. But as the research progresses step by step, such detector combinations are no longer sufficient for their needs. In order to accurately depict the internal structure that contributes to the precise control of polymer properties, in addition to molecular weight, structural features such as polymer conformation, branching, and aggregation are also key parameters that cannot be obtained by differential RI and UV UV detectors. Out.
The detection limits of the instrument restrict the research progress of Jiaotong University in the field of biopharmaceuticals. In order to break through this bottleneck, they began to consider upgrading existing instruments. For them, the ideal equipment has more features to provide them with as much detailed molecular information as possible.
When seeking the right instrument, Jiaotong University and the British Malvern Instrument Co., Ltd. (hereinafter referred to as "Malvern") contacted. Malvern is a global leader in materials and biophysical characterization, providing a wide range of high performance physical analysis solutions. Since the 1990s, Jiaotong University has been working with Malvern. Over the years, Malvern products have been recognized and trusted by the University of Communications for their outstanding performance, ease of operation and high efficiency.
After the preliminary test and expert research, Jiaotong University finally selected Malvern's quadruple detector GPC system. In addition to the differential, viscosity and PDA UV detectors, the system also includes the latest Viscotek SEC-MALS20 multi-angle light scattering detector with 20 inspection angles. These detectors are integrated into a chromatographic temperature control system that collects all detector signals simultaneously during a single test, providing the absolute molecular weights of the polymers tested, Mw, Mn, Mz, molecular weight distribution, intrinsic viscosity IV of the polymer, The Mark-Houwink curve of the polymer, the size of the polymer coils, and the composition information of the copolymer greatly enrich the characterization means and provide powerful data support for scientific research work.
Figure: Malvern Quadruple Detector GPC System
Multi-detector GPC maximizes information flow
Currently, multi-detector GPC systems are favored in most polymer development projects. The combined advantages of multiple detectors maximize experimental efficiency, allowing researchers to obtain comprehensive information about polymer structures in a short period of time. The most widely detected and most comprehensive detector combination on the market is Malvern's four-detector gel chromatography. They support and complement each other to create a detailed picture of polymer properties and structure. Especially in this multi-detector gel chromatography, Malvern pioneered the use of several innovative technologies.
Viscotek SEC-MALS 20 Multi-Angle Light Scattering Detector
Light scattering detectors are currently the most direct method for detecting the absolute molecular weight of polymers, and have been widely introduced in most GPC systems. In recent years, the industry has developed a variety of different light scattering technologies, such as right angle light scattering (RALS), small angle light scattering (LALS) and multi-angle light scattering (MALS). Among them, MALS is particularly widely used in fields related to protein or biopharmaceuticals.
When choosing a detection system, the most common concern is the number of detection points. Modern MALS technology tends to be equipped with a larger number of detection points to fit more complex scattering pattern curves, resulting in accurate molecular weight and Rg data. Viscotek SEC-MALS 20 is the most advanced static light scattering detector on the market. Malvern's detectors utilize up to 20 angles of scattered light intensity for optimum scattering angle extrapolation and accuracy for the most accurate molecular weight results. At the same time, it can also detect the molecular size Rg and provide data for the conformational study of polymers. It is worth mentioning that all of the information obtained using Malvern Viscotek SEC-MALS 20 is absolute molecular weight information, rather than the relative molecular weight information obtained by conventional molecular weight standard samples, thus further ensuring the reliability of the data.
Pioneering vertical flow cell design
An essential feature of the MALS system is its vertical flow cell design. The traditional MALS system adopts the transverse flow cell design and has the characteristics of simple structure, but the actual detection angle changes with the change of the solvent. For the mobile phase with different refractive index, the flow cell of two different materials may be needed to cope with the test, and has The disadvantage of the larger size of the pool.
For the ViscotekSEC-MALS 20 detector, Malvern opened the industry's first precedent with a vertical flow cell design that not only measures more angles, but also allows for smaller angles to measure larger physical spaces for higher accuracy. Malvern Viscotek SEC-MALS 20's flow cell is the smallest of its kind, effectively avoiding the chromatographic diffusion effects caused by large volumes. In addition, the vertical flow cell has another advantage in that its detection angle does not change with the change of the solvent refractive index, thereby avoiding the variation of the scattering angle in the horizontal flow cell design.
Second generation viscosity detector sensor
The differential viscometer detector provides a test for intrinsic viscosity to obtain information on molecular size, conformation, and structure. The viscosity detector used in Malvern's detector gel chromatography is its innovative second generation viscosity detector sensor. Compared to other sensor products in the market, it is more sensitive and resistant to acids and bases, allowing viscosity detectors to be tested in acidic mobile phases such as cation-bearing glycan samples.
Highly stable differential ( RI ) detector
Accurate detection of polymer or protein concentrations is critical to obtaining high quality molecular weight and molecular structure data. Malvern's highly stable Viscotek differential detector is suitable for multi-detector GPC systems. The Refractive Index Detector can be automatically cleaned using software control, and a carefully designed cleaning program eliminates major temperature changes and provides fast baseline recovery.
PDA detector provides a new perspective for understanding polymer composition
As an alternative concentration detector, the UV Absorption Detector is a tool that is ideally suited for analyzing the composition of polymers, such as copolymers or protein copolymerization. The Malvern PDA detector can obtain the UV absorption signal in the entire UV spectral range, thereby obtaining the effect of molecular weight change on the polymer composition from another perspective.
Practical application and feedback
The Malvern Viscotek Gel Permeation Chromatography Series detectors provide a comprehensive analytical approach to polymer structure and physical properties, enabling the industry to develop advanced polymer materials that help the biomedical industry grow and meet global sustainability. In terms of requirements, it is of great significance.
At present, Jiaotong University has applied the instrument to its biopharmaceutical-related research work. With the help of the four detectors of Malvern Viscotek, they obtained valuable molecular weight and molecular structure information of the polymer, establishing the relationship between the molecular weight and its molecular conformation and the physical properties of the polymer. Researchers at Jiaotong University can collect more data. In addition, thanks to the 100% automation control of the Malvern Viscotek GPC system, their work efficiency has also been greatly improved.
"Malvern is the leading provider of multi-detector gel permeation chromatography and has been developing new GPC detection technologies for many years, providing advanced instruments, techniques and application methods for polymer research. In this collaboration, in addition to products, Malvern also provided us with a very professional and comprehensive pre-sales application support and after-sales training to help us quickly become familiar with the instrument and ensure that it is always in the best working condition.†said Ning teacher of Shanghai Jiaotong University.
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