Gel Permeation Chromatography (GPC)
Gel Permeation Chromatography (GPC), also known as size exclusion chromatography (SEC), is based on the separation mechanism of volume exclusion. Through the stationary phase with molecular sieve properties, it is used to separate substances with low molecular weight, and can also analyze polymer homologues with different molecular volumes and the same chemical properties. Gel Permeation Chromatography is mainly used to measure the molecular weight and molecular weight distribution of polymeric materials.
The principle of GPC
The measured polymer solution passes through a chromatographic column containing gel particles of different pore sizes, and the paths available for molecules in the column are interparticle gaps and intra-particle through-pores.
When the polymer solution flows through the chromatographic column, the larger molecules are excluded from the pores of the particles and can only pass through the gaps between the particles at a faster rate, while smaller molecules can enter the pores in the particles at a much slower rate; medium-volume molecules can infiltrate into larger pores, but are blocked by smaller pores, between the above two cases.
After a certain length of chromatographic column, the molecules are separated according to the relative molecular weight, with the high molecular weight in the front and the small molecular weight in the back.
- All components are eluted before the solvent molecules are eluted, and the separation time is short.
- The elution time can be predicted, and the sample can be continuously injected.
- The separation process of gel chromatography does not rely on intermolecular forces. Generally, molecules that are not strongly retained accumulate on the chromatographic column, so the sample components will not be lost during separation, and the service life of the column will be prolonged.
- The retention time is short, the chromatographic peak is narrow, and it is easy to detect.
- Substances with similar relative molecular weights but different chemical structures cannot be completely separated and purified by gel permeation chromatography.
- Gel chromatography cannot distinguish compounds with similar molecular sizes, and the relative molecular mass difference must be more than 10% in order to be separated.
- Testing the relative molecular weight and distribution of polymer compounds;
- Testing the molecular weight and distribution breadth index of polymer compounds;
- Identifying the differences between various molecular products.
- Number average molecular weight Mn
- Weight average molecular weight Mw
- Viscosity average molecular weight Mv
- Molecular weight distribution curve
- Sample status can be liquid, powder, or block samples.
- The sample is required to have good solubility in the designated mobile phase, and the sample amount is required to be about 20 mg.
- If the sample has poor solubility, it is required to dissolve it well in advance, the concentration is required to be around 2-5 mg/ml, or provide a reasonable dissolution method, if the method is too complicated, the cost issue needs to be consulted in advance.
In conclusion, T,C&A Lab can offer GPC services that can solve materials testing related problem. Finally, please complete the form to have an expert discuss your needs.
- Dragostin, O.; etc. Molecular weight of polymers used in biomedical applications. Characterization of Polymeric Biomaterials. Woodhead Publishing, 2017. 101-121.
Note: this service is for Research Use Only and Not intended for clinical use.
- Atomic Absorption Spectroscopy (AAS)
- Atomic Force Microscope
- Auger Electron Spectroscopy
- Electron Backscatter Diffraction
- Energy Dispersive Spectrometer (EDS)
- Focused Ion Beam (FIB)
- Fourier Transform Infrared Spectroscopy (FTIR)
- Gas Chromatography - Mass Spectrometry (GC-MS)
- Gel Permeation Chromatography (GPC)
- Glow Discharge-Mass Spectrometry (GD-MS)
- IGA Gas Adsorption System
- Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)
- Ion Chromatography (IC)
- Laser Ablation-Inductively Coupled Plasma Mass Spectrometer (LA-ICP-MS) System
- Nuclear Magnetic Resonance (NMR)
- Raman Spectrometer
- Rutherford Backscattering Spectrometry (RBS)
- Scanning Electron Microscope (SEM)
- Secondary Ion Mass Spectroscopy (SIMS)
- Thin-Layer Chromatography (TLC)
- Time of Flight Secondary Ion Mass Spectrometry (TOF-SIMS)
- Total Reflection X-ray Fluorescence
- X-Ray Diffraction (XRD)
- X-Ray Fluorescence (XRF)
- X-ray Reflectivity (XRR)