MtoZ Biolabs has launched the SEC-MALS based molecular weight service to provide comprehensive determination of the absolute molecular mass of proteins. This service is widely used in studies of molecular size and mass characteristics, forming a data foundation for downstream experimental design.

Principle of SEC-MALS

SEC-MALS means SEC enables non-denaturing separation according to molecular hydrodynamic volume, and MALS calculates absolute molecular mass using multi-angle measurements of scattering intensity. This strategy is broadly applied to confirm the true molecular weight and oligomeric state of proteins while eliminating bias caused by nonspecific adsorption or abnormal retention behavior. SEC-MALS is essential for molecular weight assignment under native conformations and for evaluation of protein association, dissociation, and aggregation states, serving as a dependable analytical approach for quality characterization in structural biology and protein research.

Moraes, I. et al. Methods in Molecular Biology, 2015.

Figure 1. Diagram of an SEC-MALLS System.  

SEC-MALS Based Molecular Weight Service at MtoZ Biolabs

MtoZ Biolabs enables clients to obtain protein molecular mass analysis services centered on accurate neutral molecular weight using SEC-MALS.

• Determines the absolute molecular weight of intact proteins

• Characterizes molecular weight distribution and polydispersity

• Monitors and quantifies mass shifts of protein aggregates

• Evaluates molecular weight consistency across production batches

Our analysis delivers systematic insights into accurate neutral molecular weight and polymeric states of proteins, providing researchers with high-confidence evidence to define proteoforms and molecular properties.

Workflow of SEC-MALS Based Molecular Weight Service

1. Sample Inspection and Buffer Check

Verify protein solubility and clarity, and confirm buffer compatibility.

2. SEC Separation and Peak Quality Control

Stably separate monomeric proteins and higher-order forms using size-exclusion chromatography, controlling matrix interference and peak tailing.

3. MALS Scattering Signal Acquisition

Continuously record static light scattering signals at multiple detection angles and establish synchronized alignment with online UV/RI traces for absolute molecular mass calculation.

4. Molecular Weight and Mass Error Envelope Control

Integrate the concurrent SEC and MALS signals, input the correction factor dn/dc, and output absolute molecular mass and MW distribution signatures.

5. Interpretation and Delivery

Provide a complete molecular weight analysis report, including protein molecular weight tables, light scattering spectra, molecular weight distribution, and others.

Why Choose MtoZ Biolabs?

• High Accuracy Measurement: Confirms intact protein and subunit molecular mass with ppm-level error control.
• High Sensitivity Analysis: Captures low-abundance proteins and weak signals from aggregated states.
• Standardized Workflow: Systematic QC and mass calibration ensure comparable results across samples and batches.
• Customized Analysis: Tailored MS acquisition and data processing strategies based on sample type and study goal.
• One Stop Service: Integrates sample assessment, chromatographic separation when required, molecular mass calculation, and formal report generation.

Deliverables

• Comprehensive Experimental Details
• Materials, Instruments, and Methods
• Protein Molecular Weight Confirmation List
• Mass Spectra, Light Scattering Images
• Bioinformatics Analysis
• Raw Data Files

FAQ

Q1: What types of samples are most suitable?

A1: Soluble, clear, and high-purity protein samples are highly suitable, including recombinant proteins, antibodies, fusion proteins, and purified protein complexes. For samples containing complex matrices, high salt, or surfactants, desalting or buffer exchange is recommended to ensure stable scattering main peaks and reliable MWD calculation.

Q2: What is the service general workflow?

A2:

Q3: What data formats are provided?

A3: Standardized outputs are available in multiple formats, including

• Raw acquisition files compatible with instrument platforms

• Deconvoluted molecular weight result tables (XLSX/CSV)

• Analytical conclusion reports covering protein polymeric state, molecular weight distribution, and mass error assessments (PDF)

• Key spectra and light-scattering images (PNG/TIFF/TIFF)

If special analytical requirements exist, data formats can be customized according to project specifications.

Q4: How should I prepare and submit my samples?

A4: To ensure optimal identification results, it is recommended to prepare samples from the following aspects:

• Sample Purity: Samples should be free of turbidity or precipitation with minimized non-volatile salts and detergents. If necessary, MS-compatible desalting or buffer exchange should be performed.
• Sample Storage: Short-term at 4℃, long-term at -80℃, limiting repeated freeze-thaw cycles to reduce protein degradation.
• Sample Transport: Cold-chain shipping using ice packs or dry ice with leak-proof sealed packaging, ensuring protein solutions remain stable.
• Additional Information: Clearly annotate protein source, estimated concentration, buffer composition, and theoretical molecular weight to support light-scattering-based mass calculation and cross-batch comparability evidence.

For more information, please refer to Sample Submission Guidelines for Proteomics, Sample Submission Guidelines for Metabolomics.

Start Your Project with MtoZ Biolabs    

Contact us to discuss your experimental design or request a quote. Whether you are resolving accurate molecular weight of proteins or validating comparability across multiple protein batches, MtoZ Biolabs provides high-confidence analytical support for your research.