scholarly journals CHEMOMETRY IN UNDERGRADUATE CHEMISTRY COURSES: A PROPOSAL FOR THE USE OF MULTIVARIATE ANALYSIS IN THE DETERMINATION OF pKa

Química Nova ◽  
2014 ◽  
Author(s):  
Paulo Cesar de Souza Pereira ◽  
Camila Fabiano de Freitas ◽  
Cristiane Santi Chaves ◽  
Bianca Martins Estevão ◽  
Diogo Silva Pellosi ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Undergraduate Chemistry

Determination of the formaldehyde-to-phenol molar ratios of resol resins by infrared spectroscopy and multivariate analysis

2003 ◽  
Vol 89 (13) ◽  
pp. 3582-3586 ◽  
Author(s):  
Hilkka Holopainen ◽  
Leila Alvila ◽  
Tuula T. Pakkanen ◽  
Jouni Rainio
Keyword(s):  
Multivariate Analysis ◽  
Infrared Spectroscopy ◽  
Molar Ratios

scholarly journals Determination of the bruise degree for cherry using Vis-NIR reflection spectroscopy coupled with multivariate analysis

PLoS ONE ◽  
2019 ◽  
Vol 14 (9) ◽  
pp. e0222633 ◽  
Author(s):  
Yuanyuan Shao ◽  
Guantao Xuan ◽  
Zhichao Hu ◽  
Zongmei Gao ◽  
Lei Liu
Keyword(s):  
Multivariate Analysis ◽  
Reflection Spectroscopy

scholarly journals Multivariate Analysis of Photoacoustic Spectra for the Detection of Short-Chained Hydrocarbon Isotopologues

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2266 ◽  
Author(s):  
Alain Loh ◽  
Marcus Wolff
Keyword(s):  
Multivariate Analysis ◽  
Continuous Wave ◽  
Light Sources ◽  
Least Squares Regression ◽  
Detection Scheme ◽  
Concentration Determination ◽  
Multiple Measurements ◽  
Interband Cascade Lasers ◽  
Cascade Lasers

We report, to our knowledge, the first optical detection scheme for short-chained hydrocarbon isotopologues. The sensor system is based on photoacoustic spectroscopy (PAS). Two continuous wave, thermoelectrically cooled, distributed feedback interband cascade lasers (DFB-ICLs) with emission wavelengths around 3.33 and 3.38 μm, respectively, served as light sources. The investigations comprised the main stable carbon isotopologues of methane (12CH4, 13CH4), ethane (12CH3-12CH3, 13CH3-12CH3, 13CH3-13CH3), and propane (12CH3-12CH2-12CH3, 13CH3-12CH2-12CH3). They were selected because of their importance for numerous applications from climate and planetary research to natural gas exploration. Multiple measurements of single components in nitrogen and synthetic mixtures were conducted at room temperature and atmospheric pressure. Depending on the investigated hydrocarbon isotopologue, detection limits ranging from 0.043 ppmv to 3.4 ppmv were achieved. For a selective concentration determination, multivariate analysis (MVA) was applied. Partial least-squares regression (PLSR) was used to calculate concentrations from the PA spectra. The implementation of MVA has shown that the PA setup in principle works reliably and that the selective concentration determination of short-chained hydrocarbon isotopologues is possible.

scholarly journals In situ analysis of LiFePO4 batteries: Signal extraction by multivariate analysis

2010 ◽  
Vol 25 (2) ◽  
pp. 143-148 ◽  
Author(s):  
Mark A. Rodriguez ◽  
Mark H. Van Benthem ◽  
David Ingersoll ◽  
Sven C. Vogel ◽  
Helmut M. Reiche
Keyword(s):  
Multivariate Analysis ◽  
Neutron Diffraction ◽  
Electrochemical Reaction ◽  
Graphite Phase ◽  
Data Set ◽  
Reaction Behavior ◽  
Electrochemical Cycling ◽  
Li Ion

The electrochemical reaction behavior of a commercial Li-ion battery (LiFePO4-based cathode, graphite-based anode) has been measured via in situ neutron diffraction. A multivariate analysis was successfully applied to the neutron diffraction data set facilitating in the determination of Li bearing phases participating in the electrochemical reaction in both the anode and cathode as a function of state-of-charge (SOC). The analysis resulted in quantified phase fraction values for LiFePO4 and FePO4 cathode compounds as well as the identification of staging behavior of Li6, Li12, Li24, and graphite phases in the anode. An additional Li-graphite phase has also been tentatively identified during electrochemical cycling as LiC48 at conditions of ∼5% to 15% SOC.

scholarly journals Simultaneous Determination of Caffeine and Taurine in Energy Drinks by FT-MIR Spectroscopy Coupled with Multivariate Analysis

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Marcela González-Vázquez ◽  
Ofelia Gabriela Meza-Márquez ◽  
Tzayhri Gallardo-Velázquez ◽  
Guillermo Osorio-Revilla ◽  
José Luis Velázquez Hernández ◽  
...  
Keyword(s):  
Multivariate Analysis ◽  
Fourier Transform ◽  
Standard Error ◽  
Energy Drinks ◽  
Mid Infrared ◽  
Determination Coefficient ◽  
Caffeine Content ◽  
Mir Spectroscopy ◽  
Validation Stage

Energy drinks have been studied due to their damaging side effects on the health of their consumers when consumed in excess or when combined with alcohol. Our objective was to develop chemometric models, based on Fourier-transform mid-infrared (FT-MIR) spectroscopy, to quantify the taurine and caffeine content in energy drinks rapidly and simultaneously. The taurine and caffeine content in the 50 samples ranged between 0 and 69.51 mg/100 mL and 14.92 and 1126.17 mg/100 mL, respectively. The best prediction model was obtained with the partial least squares (PLS1) algorithm; for taurine, the following values were obtained: determination coefficient of calibration (Rc2) = 0.9999, standard error of calibration (SEC) = 0.15, determination coefficient of validation (Rv2) = 0.9997, and standard error of prediction (SEP) = 0.16; for caffeine, Rc2 = 0.9999, SEC = 0.26, Rv2 = 0.9999, and SEP = 0.32. The model developed with PLS1 showed certainty in predictions during the validation stage and during application to external samples. FT-MIR coupled to chemometrics is a reliable and fast technique (compared to conventional techniques) to quantify taurine and caffeine in energy drinks simultaneously.

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