Improving Selectivity and Sensitivity of Protein Quantitation By Lc–Hr–Ms/Ms: Determination of Somatropin in Rat Plasma

Abstract

Aim: Protein quantitation by digestion of a biological sample followed by LC–MS analysis of a signature peptide can be a challenge because of the high complexity of the digested matrix. Results/methodology: The use of LC with high-resolution (quadrupole-TOF) MS detection allowed quantitation of the 22-kDa biopharmaceutical somatropin in 60μl of rat plasma down to 25ng/ml with minimal further sample treatment. Reducing the mass extraction window to 0.01Da considerably decreased the interference of tryptic peptides, enhanced sensitivity and improved accuracy and precision. Analysis with LC–MS/MS resulted in a less favorable limit of quantitation of 100ng/ml. Conclusion: HRMS is an interesting option for the quantitation of proteins after digestion and has the potential to improve sensitivity with minimal method development.

Keywords::

• digestion
• high-resolution mass spectrometry
• HRMS
• mass extraction window
• MEW
• rhGH
• somatropin

Financial & competing interests disclosure

Samenwerkingsverband Noord-Nederland (SNN) is gratefully acknowledged for financial support (grant T3041). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.

Supplementary data

To view the supplementary data that accompany this paper please visit the journal website at: https://www.tandfonline.com/doi/suppl/10.2144/000112170