Current location: JICS Archive > Vol. 8 > No. 1 > Articles : 21

# On-Line Monitoring of a Continuous Pharmaceutical Process Using Parallel Factor Analysis and Unfolding Multivariate Statistical Process Control Representation

*M. Kompany-Zareh*

### Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731, Iran

On-line high performance liquid chromatography (HPLC) was used to monitor steady state reactions in three reactors (*K *= 3) over 48.0 h. Different numbers of chromatograms, with *J* = 1981 retention time points, were recorded for each of the three reactors. Peaks for each chromatogram were baseline corrected and aligned using correlation optimized warping (COW). To make a complete three-way data set of *I* = 266 chromatograms a cubic Hermite interpolation was performed. The applied bilinear multivariate statistical process control (MSPC) method included the unfolding PCA and the trilinear technique was PARAFAC. Unfolding in reactor (*K*) mode was the most informative. D-charts and Q-charts were applied to the data to determine samples which were out of control. Confidence limits were then applied to the D and Q-charts and variables with different behaviours from that encapsulated within the reference data set were located. Both bilinear and trilinear methods were found to be useful for process analysis.

**Keywords:** Multiway on-line continuous process monitoring, Parallel factor analysis, Unfolding multivariate statistical process control, Fault detection, High performance liquid chromatography