Methods for Molecular Weight Determination

The molecular weight is an important parameter to describe the size of molecules, which is of great significance for research and applications in the field of biopharmaceuticals. Scientists have developed various methods for molecular weight determination to accurately measure the mass or size of molecules. This article will introduce the working principles of molecular weight determination methods, to help readers understand the basic principles and application ranges of these methods.

 

Gel Electrophoresis

Gel electrophoresis is a commonly used method for molecular weight determination, especially suitable for the analysis of nucleic acids and proteins. It is based on the principle that the migration speed of molecules in an electric field is inversely proportional to their molecular weight. By performing electrophoretic separation of the sample to be tested in the gel, the molecular weight of the sample can be inferred from the relationship between the migration distance of different molecules and the standard molecular weight.

 

Mass Spectroscopy

Mass Spectroscopy is a method for accurate determination of molecular weight, suitable for the analysis of various biomolecules. It is based on the principle of mass spectrometer, which ionizes and accelerates the sample to be tested. By measuring the deflection of ions in a magnetic field and flight time, the mass of the molecule can be calculated. Mass spectrometry can provide accurate results of molecular weight determination and is widely used in quality control and drug development in the field of biopharmaceuticals.

 

Light Scattering

Light scattering is a commonly used method for determining the molecular weight of large molecules, especially suitable for the determination of polymers. It is based on the principle that the intensity of light scattered by large molecules under a light beam is proportional to their molecular weight. By measuring the intensity and angle of scattered light, the molecular weight and size of the molecule can be estimated.

 

Chromatography

Chromatography is a common method for separation and analysis, and can also be used for molecular weight determination. The molecular weight can be inferred based on the retention time of different molecules in the chromatographic column. Common chromatographic methods include gas chromatography (GC) and liquid chromatography (LC), which can be used to determine the molecular weight of small molecule organic compounds.

 

Electrophoresis

Electrophoresis is a method for determination based on the principle that the migration speed of molecules in an electric field is related to their molecular weight. Electrophoresis can be used to determine the molecular weight of charged biomolecules such as proteins, peptides, and nucleic acids. Common electrophoresis methods include polyacrylamide gel electrophoresis, isoelectric focusing, and capillary electrophoresis.

 

The methods for molecular weight determination have important significance in research and applications in the field of biopharmaceuticals. Methods such as gel electrophoresis, mass spectrometry, light scattering, chromatography, and electrophoresis provide a variety of choices for accurately determining the molecular weight of different biomolecules. Scientists choose the appropriate determination method according to the nature of the sample to be tested and the research purpose, providing a reliable means for the analysis and quality control of biomolecules.