Showing posts with label Josette EL HADDAD. Show all posts
Showing posts with label Josette EL HADDAD. Show all posts

Thursday, May 1, 2014

Abstract-Chemometrics Applied to Quantitative Analysis of Ternary Mixtures by Terahertz Spectroscopy



Université de Bordeaux, CNRS, LOMA, UMR 5798, Talence, F-33400, France
Anal. Chem., Article ASAP
DOI: 10.1021/ac500253b
Publication Date (Web): April 16, 2014
Copyright © 2014 American Chemical Society
*E-mail: bruno.bousquet@u-bordeaux.fr. Tel:+33 (0)5 40 00 28 70. Fax: +33 (0)5 40 00 69 70

Chemometrics was applied to qualitative and quantitative analyses of terahertz spectra obtained in transmission mode. A series of mixtures of three pure analytes, namely, citric acid, d-(−)fructose, and α-lactose monohydrate under various concentrations, was prepared as pressed pellets with polyethylene as binder. Then, terahertz absorbance spectra were recorded by terahertz time domain spectroscopy and analyzed. First, principal component analysis allowed one to correctly locate the samples into a ternary diagram. Second, quantitative analysis was achieved by partial least-squares (PLS) regression and artificial neural networks (ANN). The concentrations were predicted with values of relative mean square error lower than 0.9% for the three constituents. As a conclusion, chemometrics was demonstrated to be very efficient for the analysis of the ternary mixtures prepared for this study.

Wednesday, April 16, 2014

Abstract- Chemometrics applied to quantitative analysis of ternary mixtures by Terahertz spectroscopy



Josette EL HADDAD Frederick De Miollis Joyce 
Anal. Chem., Just Accepted Manuscript
DOI: 10.1021/ac500253b
Publication Date (Web): April 16, 2014
Copyright © 2014 American Chemical Society
http://pubs.acs.org/doi/abs/10.1021/ac500253b
Chemometrics was applied to qualitative and quantitative analyses of terahertz spectra obtained in transmission mode. A series of mixtures of three pure products, namely citric acid, D-(-) fructose and α-lactose monohydrate under various concentrations were prepared as pressed pellets with polyethylene as binder. Then terahertz absorbance spectra were recorded by terahertz time domain spectroscopy and analyzed. Firstly, principal component analysis allowed to correctly locating the samples into a ternary diagram. Secondly, quantitative analysis was achieved by partial least square (PLS) regression and artificial neural networks (ANN). The concentrations were predicted with values of relative mean square error lower than 0.9 % for the three constituents. As a conclusion, chemometrics was demonstrated to be very efficient for the analysis of the ternary mixtures prepared for this study.