Partial least-squares methods for spectral analyses. 1. Relation to other quantitative calibration methods and the extraction of qualitative information

Journal Article · Wed Jun 01 00:00:00 EDT 1988 · Anal. Chem.; (United States)

DOI:https://doi.org/10.1021/ac00162a020· OSTI ID:6862317

Haaland, D M; Thomas, E V

Partial least-squares (PLS) methods for spectral analyses are related to other multivariate calibration methods such as classical least-squares (CLS), inverse least-squares (ILS), and principal component regression (PCR) methods which have been used often in quantitative spectral analyses. The PLS method which analyzes one chemical component at a time is presented, and the basis of each step in the algorithm is explained. PLS calibration is shown to be composed of a series of simplified CLS and ILS steps. This detailed understanding of the PLS algorithm has helped to identify how chemically interpretable qualitative spectral information can be obtained from the intermediate steps of the PLS algorithm. These methods for extracting qualitative information are demonstrated by use of simulated spectral data. The qualitative information directly available from the PLS analysis is superior to that obtained from PCR but is not complete as that which can be generated during CLS analyses. Methods are presented for selecting optimal numbers of loading vectors for both the PLS and PCR models in order to optimize the model while simultaneously reducing the potential for overfitting the calibration data. Outlier detection and methods to evaluate the statistical significance of results obtained from the different calibration methods applied to the same spectral data are also discussed.

• Research Organization: Sandia National Labs., Albuquerque, NM (USA)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6862317
• Journal Information: Anal. Chem.; (United States), Journal Name: Anal. Chem.; (United States) Vol. 60:11; ISSN ANCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
CALIBRATION
CALIBRATION STANDARDS
CHEMICAL ANALYSIS
DATA
DATA ANALYSIS
INFORMATION
LEAST SQUARE FIT
MAXIMUM-LIKELIHOOD FIT
NUMERICAL DATA
NUMERICAL SOLUTION
OPTIMIZATION
QUALITATIVE CHEMICAL ANALYSIS
QUANTITATIVE CHEMICAL ANALYSIS
SPECTRA
SPECTROSCOPY
STANDARDS
THEORETICAL DATA