Chemometric Methods for GC-MS and LC-MS
Chemometric Methods for GC-MS and LC-MS covers methods for dealing with the discontinuous spectra produced by mass spectrometry coupled with preseparation by gas or liquid chromatography. Participants will learn how overlapping peaks can be resolved into separate peaks for each of the components and their associated single component spectra using a number of methods including Multivariate Curve Resolution (MCR) and Parallel Factor Analysis (PARAFAC). Methods for extracting high quality mass chromatograms from complex data such as resulting from LC-MS with electro spray will also be covered. Methods that extract small differences between very similar samples, such as different batches of the same material, will also be discussed. Methods for dealing with retention time variations will be discussed, including alignment methods and PARAFAC2. The course includes hands-on computer time for participants to work example problems using PLS_Toolbox.
- Self-modeling Mixture Analysis and Self-modeling Curve Resolution
- Pure variable method
- Pure spectrum method
- Analysis of multiple samples simultaneously with PARAFAC
- the PARAFAC model
- interpreting results
- potential problems due to retention shifts, etc.
- CODA (COmponent Detection Algorithm)
- the Durbin and Watson criterion
- extracting high quality mass chromatograms
- COMPARELCMS for Extracting Differences Between Similar Samples
- A new simpler algorithm
- Handling Retention Time Shifts
- Methods for alignment, COW, DTW, etc.
- Homework and Example Problems