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Monakhova Y.B.,Chernyshevsky Saratov State University | Goryacheva I.Y.,Spectral Service | Goryacheva I.Y.,Saint Petersburg State University
TrAC - Trends in Analytical Chemistry | Year: 2016

Due to diverse favorable physicochemical properties, luminescent quantum dots (QD) are widely used as labels or nanosensors for various analytical purposes. However, to the best of our knowledge there are not many reports applying chemometric approaches in nanoscience despite wide utilization of these methods in other research areas. The review addresses the usage of multivariate methods to resolve strongly overlapping signals for exploring different properties of QDs, as well as environmental characteristics. In particular, we discuss chemonetric applications for investigation of evolving luminescence signals of passive QD-based labels and active QD-based nanosensors, excitation-emission matrix (EEM) spectroscopic data and in vivo imaging of QD systems. Our review has shown that chemometrics plays an important role in the processing of luminescent nanoparticles signals and their role will definitely increase in the future. © 2016 Elsevier B.V.


Skiera C.,University of Wurzburg | Steliopoulos P.,Chemisches und Veterinaruntersuchungsamt Karlsruhe | Kuballa T.,Chemisches und Veterinaruntersuchungsamt Karlsruhe | Holzgrabe U.,University of Wurzburg | Diehl B.,Spectral Service
JAOCS, Journal of the American Oil Chemists' Society | Year: 2012

Within the course of lipid peroxidation, hydroperoxides are formed as primary products. They can be used as analytical markers to assess the deterioration status of oils and fats. Here a new 1H-NMR assay to determine the hydroperoxide amount in edible oils is presented. We were able to show that the analytical performance of the method is similar to that of the commonly used peroxide value (PV) according to Wheeler. A total of 290 edible oil samples were analyzed using both methods. For some oil varieties considerable discrepancies were found between the results obtained. In the case of black seed and olive oil, two substances could be identified that cause positive (black seed oil) and negative (olive oils) deviations from the theoretical PV expected from the NMR values. © 2012 AOCS.


Skiera C.,University of Wurzburg | Steliopoulos P.,Chemisches und Veterinaruntersuchungsamt Karlsruhe | Kuballa T.,Chemisches und Veterinaruntersuchungsamt Karlsruhe | Holzgrabe U.,University of Wurzburg | Diehl B.,Spectral Service
Lipid Technology | Year: 2012

Here we describe a novel 1H NMR assay for the determination of FFAs in edible oils. The analytical performance of the NMR assay is similar to that of the commonly used acid value (AV) method. A total of 120 edible oil samples were analysed by both approaches. Except for pumpkin seed oil, showing slight deviations, there was a good compliance between the results obtained from the two methods. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Hohmann M.,University of Wurzburg | Monakhova Y.,Spectral Service | Monakhova Y.,Chernyshevsky Saratov State University | Erich S.,Chemical and Veterinary Investigation Laboratory | And 3 more authors.
Journal of Agricultural and Food Chemistry | Year: 2015

Because the basic suitability of proton nuclear magnetic resonance spectroscopy (1H NMR) to differentiate organic versus conventional tomatoes was recently proven, the approach to optimize 1H NMR classification models (comprising overall 205 authentic tomato samples) by including additional data of isotope ratio mass spectrometry (IRMS, δ13C, δ15N, and δ18O) and mid-infrared (MIR) spectroscopy was assessed. Both individual and combined analytical methods (1H NMR + MIR, 1H NMR + IRMS, MIR + IRMS, and 1H NMR + MIR + IRMS) were examined using principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), linear discriminant analysis (LDA), and common components and specific weight analysis (ComDim). With regard to classification abilities, fused data of 1H NMR + MIR + IRMS yielded better validation results (ranging between 95.0 and 100.0%) than individual methods (1H NMR, 91.3-100%; MIR, 75.6-91.7%), suggesting that the combined examination of analytical profiles enhances authentication of organically produced tomatoes. © 2015 American Chemical Society.


Skiera C.,University of Wurzburg | Steliopoulos P.,Chemisches und Veterinaruntersuchungsamt Karlsruhe | Kuballa T.,Chemisches und Veterinaruntersuchungsamt Karlsruhe | Holzgrabe U.,University of Wurzburg | Diehl B.,Spectral Service
European Food Research and Technology | Year: 2012

Aldehydes, formed as secondary oxidation products during the autoxidation process of oils and fats, are analytical markers used to assess the lipid deterioration status. Generally, the level of aldehydes is expressed as the p-anisidine value (AV). This deterioration index is based on the reaction of the carbonyl group with p-anisidine leading to the formation of an intensively coloured Schiff base which is determined spectroscopically (UV/ViS). 1H NMR provides an alternative approach by enabling the quantification of individual aldehydes like n-alkanals, 2-alkenals or (E,E)-2,4-alkadienals. This work illustrates that the AV can be modelled as a linear combination of the NMR integrals of aldehydes. A functional relationship was derived on the basis of calibration experiments. The suitability of the model is shown by comparing the NMR-determined AVs with the classical AVs of 79 commercially available edible oils of different oil types. © 2012 Springer-Verlag Berlin Heidelberg.

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