Spectroscopy calibration

The -OH content of polymers was determined by IR spectroscopy. Calibration graphs were constructed by means of solutions of 1,4-butanediol in polydioxolane. It was ascertained that any ethylene glycol which could have been formed by hydrolysis of monomer or polymer would have been removed completely during the isolation and purification of the polymers. The smallest concentration of OH groups given here was at least twice as great as the lower detection limit. 

O. Elizalde, J.M. Asua and J.R. Leiza, Monitoring of emulsion polymerization reactors by Raman spectroscopy Calibration model maintenance, Appl. Spectrosc., 59, 1280-1285 (2005). 

Figure 12.27 (A) Scatter plot of the Hotelling P and Q residual statistics associated with the samples in the process spectroscopy calibration data set, obtained from a PCA model built on the data after obvious outliers were removed. The dashed lines represent the 95% confidence limit of the respective statistic. (B) The spectra used to generate the plot in (A), denoting one of the outlier samples.

Figure 12.29 Time-series plot of the y-residuals obtained from a PLS model developed using the process spectroscopy calibration data set (solid line), after removal of sample and variable outliers as discussed earlier. The measured y-values (dashed line) are also provided for reference.

Workman. NIR Spectroscopy Calibration Basics. In DA Burns and EW Ciurczak, eds. Handbook of Near Infrared Analysis. New York Marcel Dekker, 2001, pp. 91-128. 

The practice of weighting variables by the reciprocal of their standard deviation is common in many applications, especially where the variables have different units. In contrast this is seldom used in spectroscopy calibration, because the variable are of die same type and units, and information is usually considered to be related to broader peaks (4). A preliminary trial showed that X-variable standardization amplified e noise of the PLS model (data not shown). Since the 436 X-variables are all in the same units (ABS 520 nm) with presumably similar noise levels, they were not weighted. The Y-variables were also be kept unweighted, since the relative noise levels between X and Y variables are more or less irrelevant (S). 

Quantitative Analysis learning to use the WinLab software for furnace atomic absorption spectroscopy calibration based on standard addition no write-up required... 

Orman, B. A. and Schumann, R. A. Jr. (1991) Comparison of near-infrared spectroscopy calibration methods for the prediction of protein, oil, and starch in maize grain. J. Agric. Food Chem., 39, 883-6. 

W. Liu, W. Yang, L. Liu, and Q. Yu, Use of Artificial Neural Networks in Near-Infrared Spectroscopy Calibrations for Predicting Glucose Concentration in Urine, in 4th International Conference on Intelligent Computing, ICIC 2008, Shanghai, China, 2008, vol. 5226, p. 1040. 

The variance of the sample set used to produce NIR spectroscopy calibration equations determines both robustness and accuracy for a particular application. A calibration learning set that includes a wide variation of sample types and a large constituent range will allow a calibration... 

The pioneering works in chemometrics are summarized in some books. In a later phase chemometrics has been presented more fundamentally. Nowadays a series of books for the different aspects of chemometrics are available, such as in analytical chemistry, spectroscopy, calibration, quantitative structure-activity relationships, experimental design, chemical structures, organic synthesis, and neural networks. Research papers in chemometrics are widespread but some concentration occurs in journals of analytical chemistry, chromatography, spectroscopy, and computer chemistry. Two journals have the word chemometrics in their name Chemometrics and Intelligent Laboratory Systems and Journal of Chemometrics. Comprehensive reviews about chemometrics in analytical chemistry have appeared since 1980 every two years 1982, 1984, 1986, 1988, 1990, 1992, 1994, and 1996. ... 

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