Column: Chemometrics in Spectroscopy

Jun 01, 2014
Spectroscopy
What are the techniques and mathematics used to compute uncertainty, and the optimum methods for maintaining wavelength accuracy within instrumentation over time, when considering measurement condition changes?
Feb 14, 2014
Spectroscopy
The data show that different units of measurement have different relationships to the spectral values, for reasons having nothing to do with the spectroscopy. This finding disproves the assumption that different measures of concentration are equivalent except, perhaps, for a constant scaling factor.
Oct 01, 2013
Spectroscopy
The statistical methods used for evaluating the agreement between two or more instruments (or methods) for reported analytical results are discussed, with an emphasis on acceptable analytical accuracy and confidence levels using two standard approaches, standard uncertainty or relative standard uncertainty, and Bland-Altman "limits of agreement."
Jun 01, 2013
Spectroscopy
Calibration transfer is a series of techniques used to apply a single spectral database, and the calibration model developed using that database, to two or more instruments. Here, we review the mathematical approaches and issues related to the calibration transfer process.
May 01, 2013
Spectroscopy
Part II of this series surveys the issues related to instrument measurement differences associated with the calibration transfer problem.
Feb 01, 2013
Spectroscopy
A definition for calibration transfer is proposed, along with a method for evaluating it, based on recent discoveries about the nature of light absorbance in spectroscopic analysis.
Oct 01, 2012
Spectroscopy
In the final installment of this series, the main problem is solved using the CLS algorithm to find that the spectroscopy is sensitive to the volume fractions of the various components in a mixture.
May 01, 2012
Spectroscopy
Here, the results are examined after repeating the original experiment in another laboratory.
Feb 01, 2012
Spectroscopy
The series on classical least squares continues with a comparison of experimental results and theoretical expectations.
Oct 01, 2011
Spectroscopy
Continued discussion of the classical least squares approach to calibration, with a focus on the reconstruction of mixtures
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