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# Quantitative Determination of Sugar Cane Sucrose by Multidimensional Statistical Analysis of their Mid-Infrared Attenuated Total Reflectance Spectra*

Applied Spectroscopy (Impact Factor: 1.94). 01/1991; 45(2):166-172. DOI: 10.1366/0003702914337470

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**ABSTRACT:**An instrumental method based on a chemometric model of the medium region of the infrared (MIR) was developed to analyse total sugar content and the proportions of glucose, fructose and sucrose. In order to construct the model, a set of 127 standard aqueous solutions of different sugars in the concentration range 0-20% (w/v) were prepared and analysed in the interval 4900-700 cm(-1). The MIR was transformed by normalisation, correction of baseline using the second derivative, and suppression of the signals of water and carbon dioxide. The region between 1150 and 950 cm(-1) showed the highest correlation between signal and concentration. The correlation coefficient for total sugar content was 0.956, whilst those for glucose, fructose and sucrose were 0.982, 0.972 and 0.992, respectively. The method was validated using a set of 28 samples of nectar which had been assayed by chromatographic and refractometric methods. The method shows potential utility for the prediction of nectar sugar components.Phytochemical Analysis 01/2003; 14(5):319-24. · 2.48 Impact Factor -
##### Article: Choice of a Particular Mathematical Distance for the Classification of Biological FTIR Spectra.

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**ABSTRACT:**Several methods have been proposed of improving the precision of quantitative measurements of biological components using Mid-Infrared spectra. Mid-FTIR spectra of natural products are often very similar and could contain an important number of absorbance values. It is necessary to emphasize on their differences by processing the data and by the application of a particular mathematical distance to measure the dissimilarities between spectra.Here, the most dissimilar individuals are obtained from a whole spectral collection constitutive of the calibration set: the other samples are then classified according to the mobile centres method. Multidimensional analysis and principal component regression are extensively used for the construction and classification methods. The sucrose content in samples from a verification set were predicted (i) before classification in which case a prediction equation was established by PCR on the whole calibration set, (ii) after classification using the euclidian distance, from the prediction equations established from each sub-class, (iii) after classification using the correlation distance, from the prediction equations established from each sub-class. The predicted values are improved after classification whether the euclidian or the correlation distance is used for the classification of the samples. The mean and standard deviation values of the difference between observed and predicted values are respectively 4.7×10 and 0.341 before classification, 1.7×10 and 0.272 after classification using the euclidian distance and 6×10 and 0.263 after classification using the correlation distance; the distribution of the individuals are not similar according to the mathematical distance used. When the correlation distance is used, 17.95% of the individuals initially classified using the euclidian distance undergo a change of sub-class. In fact 2 of the 3 sub-classes become more homogeneous with regard to the chemical values than when the euclidian distance is used for the classification.With the aim of measuring concentration of sucrose with a good precision, the correlation distance appear to be the more appropriate mathematical distance for the the classification of Mid-infrared spectra of the biological sampes studied here (sugar cane juices).Spectroscopy Letters 09/1996; 29:1103-1120. · 0.67 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**Complex-formation between carbohydrates and cations could have important biological implications.In this work, Mid-Infrared spectra of pure sucrose solutions and of biological solutions containing sucrose and potassium ions (K+) were investigated by Principal Component Analysis (PGA).By direct examination of the Mid-Infrared spectra of the biological solutions containing K ions, no interactions between the cations and sucrose molecules could be observed. However, when the spectral pattern obtained by PCA and which is associated with sucrose, was examined, splitting and shifts in the characteristic absorption bands were observed owing to interactions between sucrose molecules and K ions. The 997 cm-1 peak which had a visible shoulder at 991 cm-1 and that is observed in pure solutions, was decomposed in the biological solutions into 3 distinct peaks at 1004, 996 and 990 cm-1. The two peaks centered at 1053 cm-1 were split into 3 peaks: 1060, 1051, 1045 cm-1. Hence by PCA, shoulders were characterized in biological solutions and more distinct peaks could be observed. These split and shift phenomena are similar to those obtained when crystalline sugar salts were investigated. This type of interaction, involving potassium ions and sucrose molecules, would be responsible for the storage of this cation which role is essential in plant metabolism.Spectroscopy Letters 10/1996; 29:1353-1365. · 0.67 Impact Factor

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