YMC i-Mail October 2023

New Application Note

Charge variant analysis of an IgG4 type mAb via AEX-MS

Cation exchange chromatography (CEX) is commonly used to characterise the charge heterogeneity of monoclonal antibodies (mAbs) with a high isoelectric point (pI). More and more IgG4-based mAbs with lower pIs are now being developed. Therefore, anion exchange chromatography (AEX) is an alternative approach.

This application demonstrates that the charge heterogeneity of an IgG4-based mAb can be successfully evaluated using a strong anion exchange column, BioPro IEX QF, in conjunction with MS detection.

Download the Application Note for full method details.

Please visit our homepage or download the YMC Biochromatography Columns catalogue for more information on YMC’s BioLC solutions.

Tech Note

Analysis of non-denatured and denatured siRNA using AEX

siRNAs are typically analysed by ion pair reversed phase chromatography (IP-RP) or anion exchange chromatography (AEX). Different chromatographic conditions allow the analysis of double-stranded duplexes (non-denaturing) or single strands (denaturing conditions).

This technical note describes the method development for non-denatured and denatured siRNA using a non-porous BioPro IEX QF column.

Various method parameters are considered:

  • Influence of pH, salts and temperature
  • Organic solvents
  • Additives to the mobile phase

In addition, various method parameters for purification are also described.

Please refer to the Technical Note for full details.

Please visit our homepage or download the YMC Oligonucleotide columns brochure for more information on YMC’s oligonucleotide solutions.

Figure: Analysis of the siRNA duplex, sense strand and antisense strand with optimal gradient slope at denaturing conditions.

Expert tipp

How to calculate the molecular weight of nucleic acids

Choosing the correct particle pore size in SEC for oligonucleotide analysis is challenging. Usually only the length of the nucleic acid is provided. However, the molecular size suitable for an SEC stationary phase is usually molecular weight (MW) dependent.

Therefore, this Expert Tip provides formulae for calculating the MW of single-stranded (ss) or double-stranded (ds) DNA/RNA. It also includes typical MWs of poly(dT) oligonucleotides and naturally occurring RNAs.

Download the full Expert Tip for all the formulas you need to calculate the MW of your oligonucleotides.