Temat: Chemometrics - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Chemometrics as a tool for plant - inscet ecological studies
Autorzy:: Szafranek, J
Nawrot, J.
Szafranek, B.
Malinski, E.
Powiązania:: https://bibliotekanauki.pl/articles/65215.pdf
Data publikacji:: 2001
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: terpene
pine needle
sesquiterpene
ant
chemometrics
insect
plant
Opis:: The process of plant selection by insects is mediated by repellents and attractants. Several compounds may be involved in this interaction. Thus intraspecific variation of the compounds concentration play an important role in the herbivory. The best tool for the characteristic of this variation is chemometrics. The strategy of the analysis with the use of literature data on terpenes and sesquiterpenes variations in Pinus caribaea needles in relation to Atta laevigata herbivory is exemplified herein. Simple cluster analysis and principal components analysis were used for the data study. Two factors were found to be sufficient to describe total variation in more than 90%. Factor 1 is responsible for repellent properties. From factor loading, the relevant chemical compounds were identified.
Wiele różnych substancji chemicznych zawartych w roślinach wpływa na zachowanie owadów, pełniąc funkcje repelentów lub atraktantów. Często nie pojedyncze związki, lecz ich mieszaniny o określonym składzie są aktywne semiochemicznie. Zmienność składu lotnych roślinnych substancji semiochemiczych można oceniać metodami chemometrycznymi w celu znajdywania składników istotnych w ekologicznej interakcji. Przeprowadzono pełną analizę chemometryczną danych literaturowych dotyczących zmian składu terpenów i seskwiterpenów z igieł sosny Pinus caribaea w odniesieniu do żerowania mrówek Atta laevigata. Do klasyfikacji danych zastosowano metodę analizy wiązkowej i metodę głównych składników. Dla opisu ponad 90% zmienności składu wystarczyło zastosować dwa faktory opisujące dane dotyczące drzew defoliowanych i niedefoliowanych. Metodą analizy chemometrycznej z ładunków faktorów zidentyfikowano związki chemiczne istotne w oddziaływaniach ekologicznych.
Źródło:: Journal of Plant Protection Research; 2001, 41, 4
1427-4345
Pojawia się w:: Journal of Plant Protection Research
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Measurement data processing in spectrophotometric analysers of food. Review paper
Autorzy:: Morawski, R. Z.
Powiązania:: https://bibliotekanauki.pl/articles/221182.pdf
Data publikacji:: 2012
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: spectrophotometry
chemometrics
spectral data processing
food analysis
wine analysis
Opis:: Spectrometry, especially spectrophotometry, is getting more and more often the method of choice not only in laboratory analysis of (bio)chemical substances, but also in the off-laboratory identification and testing of physical properties of various products, in particular - of various organic mixtures including food products and ingredients. Specialised spectrophotometers, called spectrophotometric analysers, are designed for such applications. This paper is on the state of the art in the domain of data processing in spectrophotometric analysers of food (including beverages). The following issues are covered: methodological background of food analysis, physical and metrological principles of spectrophotometry, the role of measurement data processing in spectrophotometry. General considerations are illustrated with examples, predominantly related to wine and olive oil analysis.
Źródło:: Metrology and Measurement Systems; 2012, 19, 4; 623-652
0860-8229
Pojawia się w:: Metrology and Measurement Systems
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Comparison of five SVD-based algorithms for calibration of spectrophotometric analyzers
Autorzy:: Wagner, J.
Morawski, R. Z.
Miękina, A.
Powiązania:: https://bibliotekanauki.pl/articles/220564.pdf
Data publikacji:: 2014
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: spectrophotometry
chemometrics
singular value decomposition
regularisation
food analysis
edible oils analysis
Opis:: Spectrophotometry is an analytical technique of increasing importance for the food industry, applied i.a. in the quantitative assessment of the composition of mixtures. Since the absorbance data acquired by means of a spectrophotometer are highly correlated, the problem of calibration of a spectrophotometric analyzer is, as a rule, numerically ill-conditioned, and advanced data-processing methods must be frequently applied to attain an acceptable level of measurement uncertainty. This paper contains a description of four algorithms for calibration of spectrophotometric analyzers, based on the singular value decomposition (SVD) of matrices, as well as the results of their comparison - in terms of measurement uncertainty and computational complexity - with a reference algorithm based on the estimator of ordinary least squares. The comparison is carried out using an extensive collection of semi-synthetic data representative of trinary mixtures of edible oils. The results of that comparison show the superiority of an algorithm of calibration based on the truncated SVD combined with a signal-to-noise ratio used as a criterion for the selection of regularisation parameters - with respect to other SVD-based algorithms of calibration.
Źródło:: Metrology and Measurement Systems; 2014, 21, 2; 191-204
0860-8229
Pojawia się w:: Metrology and Measurement Systems
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: UV-Vis spectroscopic detection coupled with chemometrics for the measurement of mixed organic acids in water samples enriched by radial electric focusing solid phase extraction
Autorzy:: Guo, Y.
Liu, X.
Liu, J.
Bian, X.
Zhang, Q.
Pan, J.
Wan, D.
Powiązania:: https://bibliotekanauki.pl/articles/221808.pdf
Data publikacji:: 2018
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: chemometrics
UV-Vis spectrophotometer
radial electric focusing solid phase extraction
mixed organic acids
Opis:: Due to the difficulty of detecting traces of organic acid mixture in an aqueous sample and the complexity of resolving UV-Vis spectra effectively, a combinatory method based on a self-made radical electric focusing solid phase extraction (REFSPE) device, UV-Vis detection and partial least squares (PLS) calculation is proposed here. In this study, REFSPE was used to enhance the extraction process of analytes between the aqueous phase and the membrane phase to enrich the trace of mixed organic acid efficiently. Then, the analytes, which were eluted from the adsorption film by ethanol with the assistance of an ultrasonic cleaning machine, were detected with UV-Vis spectrophotometry. After that, the PLS method was introduced to solve the problem of overlapping peaks in UV-Vis spectra of mixed substances and to quantify each compound. The linearly dependent coefficients between the predicted value of the model and the actual concentration of the sample were all higher than 0.99. The limit values of detection for benzoic acid, phthalic acid and p-toluene sulfonic acid were found at 9.9 μg/L, 12.2 μg/L and 13.8 μg/L with the relative recovery values between 84.8% and 117.9%. The RSD (n = 20) values of each component are 1.17%, 1.11% and 0.86%, respectively. Therefore, the proposed combined method can determine traces of complex materials in an aqueous sample efficiently and has wonderful potential applications.
Źródło:: Metrology and Measurement Systems; 2018, 25, 2; 317-329
0860-8229
Pojawia się w:: Metrology and Measurement Systems
Dostawca treści:: Biblioteka Nauki

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