Attenuated total reflection fourier transform infrared spectroscopy based methods for identification of chromatography media formulations used in downstream processes

Abstract

Chromatographic media play a crucial role in the downstream processing of biotechnology products. The physical and chemical properties of these processing aids are mostly monitored by expensive and time-consuming preparative tests, but spectroscopic techniques may also be used to measure chromatographic media samples. In this study, chromatographic media formulations used in downstream processes were investigated using attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy. Samples were measured both in original suspension form and after drying to examine the possibilities of a potential spectroscopic method without sample preparation. Principal component analysis (PCA) was employed to identify the spectral differences among the formulations with distinct support matrices and functional groups and soft independent modeling of class analogy (SIMCA) was performed to creating classification models for identification of chromatography media. To increase the number of samples in the SIMCA, simulated spectra were generated based on the experimental spectra. PCA models indicated that spectra of samples in original suspension form and after drying contained similar information about the chemical properties of chromatographic media samples. Moreover, during the classification of spectra based on SIMCA, both measurement techniques gave high sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) results. These results show that ATR FT-IR could be applied as a simple alternative method for monitoring the chromatography media samples. This technique is also feasible without sample preparation. Thereby the multi-hours drying steps may be omitted, the measurements can be performed in a few minutes, and the potential effects of sample preparations can be eliminated.

Keywords: Chromatography media; Downstream process; Fourier transform infrared spectroscopy; Principal component analysis; Simulated spectra; Soft independent modeling of class analogy.