Absolute quantification of proteins by ICP/MS

Although drug products issued from biotechnology have been on the market for many years, accurate protein quantification remains a challenge. Commonly used colorimetric methods such as Lowry, Bradford or BCA lack precision and are affected by interferences and matrix effects, while their accuracy strongly depends on the protein used for calibration. LC‑MS/MS quantification of specific tryptic peptides also shows limited reproducibility due to digestion variability.

To address the need for a fast and accurate analytical method capable of quantifying a protein or peptide without the use of a specific reference substance, we have developed and validated an isotope dilution ICP‑MS method based on sulphur determination.

The full study sheet is available for download.