Multicomponent Determination of Chlorinated Hydrocarbons Using a Reaction-based Chemical Sensor. Part 2. Chemical Speciation Using Multivariate Curve Resolution

Tauler, Romà; Smilde, Age K.; Henshaw, John M.; Burgess, Lloyd W.; Kowalski, Bruce R.

doi:10.1021/ac00092a009

Cited by 75 publications

(37 citation statements)

References 25 publications

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“…The application of multivariate calibration techniques to near-infrared (NIR) spectroscopic measurements to extract information about chemical species in a system has been widely reported [1][2][3]. In those cases where the scattering effects are negligible, such as in mixtures of liquids, chemical characterization requires resolving the problem of overlapping absorption peaks.…”

Section: Introductionmentioning

confidence: 99%

Empirical preprocessing methods and their impact on NIR calibrations: a simulation study

Thennadil

Martin

2005

Journal of Chemometrics

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The extraction of chemical information from dense particulate suspensions, such as industrial slurries and biological suspensions, using near-infrared (NIR) spectroscopic measurements is complicated by sample-to-sample path length variations due to light scattering. Empirical preprocessing techniques such as multiplicative scatter correction (MSC), extended MSC and derivatives have been applied to remove these effects and in some cases have shown promise. While the performance of these techniques and other related approaches is known to depend on the nature and extent of the variations and on the measurement configuration, detailed investigations into the efficacy of these approaches under various conditions have not been previously undertaken. The main obstacle to carrying out such investigations has been the lack of, and the difficulty in obtaining, an accurate and comprehensive experimental data set. In this work, simulations that generate 'actual' measurements were carried out to obtain 'experimental' spectroscopic data on particulate systems. This was achieved by solving the exact transport equation for light propagation. A model system comprising four chemical components with one consisting of spherical submicron particles was considered. Total diffuse transmittance and reflectance data generated through simulations for moderate particle concentrations were used as the basis for examining the effect of particle size variations and measurement configurations on the efficacy of a number of preprocessing techniques in enhancing the performance of partial least squares (PLS) models for predicting the concentration of one of the non-scattering chemical species. Additionally, a form of extended multiplicative signal correction based on considerations arising from fundamental light scattering theory is proposed and found to perform better than the other techniques for the cases considered in the study.

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Section: Introductionmentioning

confidence: 99%

Empirical preprocessing methods and their impact on NIR calibrations: a simulation study

Thennadil

Martin

2005

Journal of Chemometrics

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“…The analysis of the absorbance changes as a function of time was carried out utilizing two chemometric techniques: evolving factor analysis and multivariate curve resolution (MCR) [48]. The first approach, (window) evolving factor analysis, is a useful technique for determining the number of absorbing components present at any time during the experiment.…”

Section: Kinetic Study Of the Reduction Of Fe III (P)(cl) By Thiosulfatementioning

confidence: 99%

Electrochemistry and spectroscopy of sulfate and thiosulfate complexes of iron porphyrins

Crawford

2002

Inorganica Chimica Acta

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Abstract:The electrochemical and spectroscopic properties of the complex formed by the addition of thiosulfate to ferric porphyrins were examined. The NMR spectrum of the thiosulfate-ferric porphyrin complex was consistent with a high-spin ferric complex, while the EPR spectrum at liquid nitrogen temperatures indicated that the complex under these conditions was low-spin. Such behavior has been previously observed for other ferric-porphyrin complexes. The visible spectra were characterized by a shift in the Soret band to higher energies, with smaller changes in the longer wavelength region. The complex was reasonably stable in DMF, but slowly reduced over several hours to Fe II (TPP) and S4O6 2-. The voltammetric behavior of the thiosulfate complex in DMF consists of two waves, the first of which was irreversible. The

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“…For the first implementation of the MLE with these spectra we let a = [ : k.:p],withk=l. Figures10,11,and12 exhibit the estimates of the pure components (averaged over 1 0 independent realizations of sample spectra) obtained by both versions of the MLE along with the pure components obtained SIMPLISMA and MCR. It is interesting to note that the MLE estimates (given SIMPLISMA as initial estimates) are significantly different than the SIMPLISMA estimates.…”

Section: Aged Neoprene Imagementioning

confidence: 99%

Improved Materials Aging Diagnostics and Mechanisms through 2D Hyperspectral Imaging Methods and Algorithms

Haaland¹,

Wehlburg²,

Martin³

et al. 2002

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The availability of new commercial hyperspectral imaging infrared spectrometers makes possible the quantitative analysis of materials without the need for standards. In the course of achieving this goal, we have developed a new family of augmented classical least-squares (ACLS) algorithms that have important improvements over other quantitative multivariate calibration methods. The new ACLS methods are described and their application to hyperspectral image analysis is presented. Demonstration is given for the use of ACLS methods to improve the quantitative analysis of hyperspectral image data when chromatic aberrations are present in the system. A comparison of several multivariate curve resolution methods to estimate purecomponent spectra without standards is presented. Finally, improvements to the multivariate curve resolution methods used to perform quantitative spectral analysis without standards are also presented. This report is a compilation of unpublished works describing these methods. Along with reference published and accepted journal papers, this body of work demonstrates the successful completion of the goals of this project. INTRODUCTIONIn this three-year research project, we set out to develop new methods of analysis of twodimensional hyperspectral Fourier transform infrared (FT-IR) images collected from a new generation of commercial FT-IR imaging spectrometers. The goal was to develop and apply new hyperspectral image analysis methods to the investigation of the aging of polymeric materials. We have accomplished this goal and have developed a whole new family of multivariate calibration methods that significantly improve the qualitative and quantitative analysis of spectral data whether the data are from hyperspectral images or from other sources. This report is a compilation of appendices from journal preprints, a patent specification, and another report that were all generated in part or in whole from this Laboratory Directed Research and Development (LDRD) project. Patent applications, published journal papers, and submitted journal papers related to this project are referenced but not included in this report.Because hyperspectral image data were not available at the beginning of this project, we initiated the development of a new classical least squares/ partial least squares (CLSPLS) hybrid multivariate analysis algorithm that was to create the basis of our hyperspectral image analyses. This hybrid algorithm was developed and programmed into several software codes. Celeste Drewien documented the implementation of the CLS/PLS hybrid algorithm for parallel processing computers.[l] The theory of the hybrid algorithm and an application to updating multivariate calibration models for the presence of unmodeled sources of near-infrared spectral variation in dilute aqueous solutions has also been published. [2] In the course of developing the hybrid algorithm, a significant improvement to the original CLS multivariate analysis algorithm[3-51 was developed. The improvement was called pre...

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Multicomponent Determination of Chlorinated Hydrocarbons Using a Reaction-based Chemical Sensor. Part 2. Chemical Speciation Using Multivariate Curve Resolution

Abstract: Multicomponent determination of chlorinated hydrocarbons using a reaction-based chemical sensor.2. Chemical speciation using multivariate curve resolution. Tauler, R.; Smilde, A.K.; Henshaw, J.M.; Burgess, L.W.; Kowalski, B.R.

Cited by 75 publications

References 25 publications

Empirical preprocessing methods and their impact on NIR calibrations: a simulation study

Empirical preprocessing methods and their impact on NIR calibrations: a simulation study

Electrochemistry and spectroscopy of sulfate and thiosulfate complexes of iron porphyrins

Improved Materials Aging Diagnostics and Mechanisms through 2D Hyperspectral Imaging Methods and Algorithms

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