Molecular Weight Determination Service

Molecular Weight Determination Service

Service Details


Molecular Weight Determination Service

The molecular weight of biopharmaceuticals such as proteins is a direct indicator of product performance and activity. Accurate molecular weight determination allows us to assess the correctness of the primary protein sequence, the presence of mutations and post-translational modifications, possible degradation, homogeneity, and the extent of isotope incorporation during labeling. Various regulatory guidelines require accurate measurement of the intact molecular weight of biopharmaceuticals. Therefore, it is necessary to determine the molecular weight of recombinant proteins and key subunits by fast and accurate methods. Currently, there are two types of mass spectrometry used for molecular weight analysis: matrix-assisted laser desorption/ionization (MALDI-TOF) and electrospray ionization (ESI-MS). These two methods have their own advantages and applications, and can be used to determine the molecular weight of various protein samples, meeting the needs of various protein molecular weight analysis including peptide fingerprint analysis and protein identification.

Our Services

Since primary structure is the most basic level of protein drugs, molecular weight is a key parameter to determine. Gaining insight into the molecular weight of unmodified proteins is helpful for the initial assessment of the function of biopharmaceutical molecules.

As a competent partner for the biopharmaceutical industry, Creative Proteomics provides a complete and professional molecular weight determination service on the basis of advanced mass spectrometry experience. Whether you need protein spectrum confirmation or peptide fingerprinting analysis, protein identification and various protein molecular weight analysis, Creative Proteomics can provide customized solutions to meet your needs.

At Creative Proteomics, our team of experts has established advanced platforms with both MALDI-TOF and ESI-MS technologies, which can be used to determine the molecular weight of various biopharmaceuticals, including antibodies, vaccines, protein drugs and peptides.

  • Using MALDI-TOF-MS for Molecular Weight Analysis

MALDI-MS analysis allows determination of the intact molecular weight of by providing an average molecular weight. Creative Proteomics uses matrix-assisted laser desorption ionization time-of-flight mass spectrometry ( MALDI-TOF-MS ) to perform intact molecular weight analysis of heterogeneous glycoproteins, which is suitable for intact mass determination of biopharmaceuticals with molecular weights below 25kDa.

It is worth noting that online liquid chromatography and electrospray mass spectrometry detection (LC/ES-MS, Q-TOF) cannot assess the intact molecular weight of highly heterogeneous glycoproteins in fully glycosylated form. This is due to the presence of glycoforms that cannot be resolved within the mass spectrometer, making it impossible to perform a complete molecular weight deconvolution of the data.

  • Using ESI-MS for Molecular Weight Analysis

Unlike MALDI-TOF-MS analysis, ESI-MS analyzes multiple charge signals obtained by electric spray, and speculates the precise molecular weight through deconvolution, which is recommended for molecular weight identification of protein substances with molecular weight of larger than 25kDa.

Advantages of Our Molecular Weight Determination

  • Comprehensive analytical techniques ensure reliable determination of every element of intact protein analysis.
  • Ionization and accurate mass analysis of proteins can reach more than 100,000 Da at low with the accuracy more than 0.1%.
  • For mass spectrometry with a mass accuracy of 5-10 ppm, more accurate molecular mass measurements can be obtained.
  • Quick turnaround time.
  • Customized service.

Creative Proteomics is a reliable biopharmaceutical partner. Our professional team can provide customers with professional molecular weight determination service, Additionally, we will assist you in designing the research program that best suits your purpose and advances your research. Please contact us immediately if you are interested in our services.


  1. Strupat K. (2005) Molecular weight determination of peptides and proteins by ESI and MALDI. Methods Enzymol. 405:1-36.

For research use only, not intended for any clinical use.

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