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Titre du Document
Quantitative determination of hydroperoxides by Fourier transform infrared spectroscopy with a disposable infrared card
Auteur(s)
MA K. ; DE VOORT F. R. V. ; ISMAIL A. A. ; ...
Résumé
Disposable polyethylene infrared cards (3M IR cards) were investigated for their suitability for the quantitative determination of peroxide value (PV) in edible oils relative to a conventional transmission flow cell. The analysis is based on the stoichiometric reaction of triphenylphosphine (TPP) with hydroperoxides to produce triphenylphosphine oxide (TPPO). Preliminary work indicated that the cards, although relatively consistent in their pathlength (±1%), had an overall effective pathlength variation of ±∼5%, caused by variability in loading of the oil onto the cards. This loading variability was reduced to <0.5% by developing a normalization protocol that is based on the peak height of the ester linkage carbonyl overtone band at 3475 cm-1, which allowed one to obtain consistent and reproducible spectra. The standard PV calibration approach, based on the TPPO peak height at 542 cm-1, failed because of unanticipated card fringing in the region where the measurements were being made. However, the development of a partial-least-squares (PLS calibration provided a means of eliminating the interfering effect of the fringes and allowed the TPPO band to be measured accurately. An alternate approach to the standardized addition of TPP reagent to the oil was also investigated by impregnating the 3M IR cards with TPP, thus allowing the reaction to take place in situ. The spectral analysis protocols developed (normalization/calibration) were programmed to automate the
Editeur
Springer
Identifiant
ISSN : 0003-021X
Source
Journal of the American Oil Chemists' Society A. 1998, vol. 75, n° 9, pp. 1095-1101 [bibl. : 15 ref.]
Langue
Anglais
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