Figure 5. (a ) Raman spectra for different antibody
types; (b ) plot of Qr versus Tr2 for a
principal component analysis (PCA) model developed using the spectra in
(a) 95% confidence level. Decision criterion: Qr ≤ 1.5, pass; Qr
> 1.5, fail.
4. Conclusion
The combination of Raman spectroscopy
and PCA achieved the level of specificity needed to differentiate the
activity of solution-based protein products. Handheld devices present
the advantage of providing quick results, with initial screening
possibly performed on the field by the end-user in a single step in less
than 5 min, rather than having to send the samples to the laboratory.
Furthermore, other CQAs, such as appearance, purity of SEC-HPLC, charge
heterogeneity of CEX-HPLC, and bioassay, verified the results of the mAb
identification by Raman spectroscopy. The results of the mAb
identification by Raman spectroscopy changed in response to the other
CQAs. Therefore, mAb identification by Raman spectroscopy based on the
PCA of multivariate algorithms can be used as a novel and reliable tool
for mAb identification. Different types of antibody identification can
be performed by Raman. A nondestructive measurement technique should
always be preferred.