Multivariate Curve Resolution With Alternating Least Squares: Description, Operation and Aplications

Março, Paulo Henrique; Valderrama, Patrícia; Alexandrino, Guilherme L.; Poppi, Ronei J.; Tauler, Romà

doi:10.5935/0100-4042.20140205

Cited by 11 publications

(17 citation statements)

References 1 publication

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“…The number of components is estimated using the singular value decomposition algorithm (SVD). 21,23 Initial estimates in MCR-ALS can be concentration profiles or spectra. They can be obtained from previous knowledge about the system if available, such as the pure spectra of some of the components in the system.…”

Section: Chemometric Analysismentioning

confidence: 99%

Application of a Chemometric Method to Interpret Spectrophotometric Data Obtained for Degradation of an Organic Dye in Water Using Manganese Oxide

Cosendey

Neves

Miranda

et al. 2020

J. Braz. Chem. Soc.

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Birnessite type manganese oxide (δ-MnO 2) was synthesized for use in degradation of the cationic dye methylene blue in aqueous solution. The material was characterized using infrared spectroscopy, X-ray diffraction, and Brunauer-Emmett-Teller (BET) surface area calculations. The removal of the dye from aqueous solutions was evaluated considering the effects of the following variables: pH, manganese oxide concentration, contact time, and temperature. UV-Vis spectroscopy analyses indicated achievement of 99 and 95% removal of methylene blue (7 mg L −1) at pH 2.0 and 4.0, respectively, after 120 min of contact with the birnessite (100 mg L −1). At higher pH of 6.0 and 8.0, removals of around 99 and 80%, respectively, were obtained after a longer time of 1860 min. Analyses of total organic carbon (TOC) revealed that 80% reduction of organic matter was obtained at pH 4.0. The method of multivariate curve resolution-alternating least squares (MCR-ALS) was used together with UV-Vis spectroscopy to evaluate the removal process, confirming the degradation of methylene blue. Thionine (λ max = 601 nm) was identified as one of the byproducts of N-demethylation of methylene blue. The results indicated that the degradation process started with N-demethylations of the methylene blue molecule.

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Section: Chemometric Analysismentioning

confidence: 99%

Application of a Chemometric Method to Interpret Spectrophotometric Data Obtained for Degradation of an Organic Dye in Water Using Manganese Oxide

Cosendey

Neves

Miranda

et al. 2020

J. Braz. Chem. Soc.

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“…Curve resolution is a chemometric tool that has been employed for pseudo univariate calibration [2,9,10]. This tool promotes the separation of the analyte signals without the need for physical separations [11]. MCR-ALS is a curve resolution chemometric tool that aims to resolve signal mixtures by recovering pure spectra and its relative intensity for the analytes in a sample [11][12][13].…”

Section: Technical Notementioning

confidence: 99%

“…This tool promotes the separation of the analyte signals without the need for physical separations [11]. MCR-ALS is a curve resolution chemometric tool that aims to resolve signal mixtures by recovering pure spectra and its relative intensity for the analytes in a sample [11][12][13]. Then, this chemometric tool can be applied for quantification when that relative intensity profile for the analyte of interest is employed in the construction of a pseudo univariate calibration curve [11].…”

Section: Technical Notementioning

confidence: 99%

Pseudo-univariate calibration as an analytical tool to determine antioxidant activity: An alternative to DPPH method applied to the evaluation from extracts of turmeric powder

Valderrama¹,

Laczkowski²,

Gonçalves³

et al. 2019

Br J Anal Chem

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A pseudo-univariate calibration model was proposed as an alternative method to determine the antioxidants activity (%RSA) in extract from turmeric powder by using the relative intensity from multivariate curve resolution with alternating least squares (MCR-ALS) from near-infrared (NIR) spectra. An extraction was performed by using an ultrasound with probe, ethanol 70% and time 15 minutes. For pseudo-univariate calibration, eight independent samples were prepared from the curcuminoid extracts. NIR spectra were collect from 900 to 1700 nm, and to these samples the percentage of inhibition of DPPH was determined with reference method. The signal for antioxidants was isolated from the signal to the other analytes in the sample by applying MCR-ALS to the NIR spectra. The relative intensity profile related to the antioxidants was employed in a pseudo-univariate calibration against the %RSA obtained by the reference conventional method based on DPPH. The results of the %RSA determination in four independent samples with mean %RSA (obtained by the reference method) of 90.26% show a mean %RSA of 87.5%, showing the possibility of %RSA determination directly from NIR spectra of turmeric powder extracts by using the multivariate resolution method MCR-ALS.

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“…A forma de calcular a porcentagem da variância explicada é descrita na Equação 5 e o ideal é que 100% da informação original seja expressa pelo modelo, sendo portanto desejado um valor para R 2 próximo a esse. 37,38 (…”

Section: Resolução Multivariada De Curvas Com Mínimos Quadrados Alterunclassified

“…Essa ferramenta foi sendo aperfeiçoada e hoje conta com uma atualização, que oferece opções adicionais de restrições, como a restrição de correlação e a inclusão de modelos pré-definidos (hard-modeling), além de formas mais eficientes de apresentação dos resultados. 39 Em 2014, Março et al 37 publicaram uma completa revisão, em língua portuguesa, descrevendo os aspectos teóricos e os avanços do método até então. São discutidos pontos como o uso de estimativas iniciais, a otimização pelo ALS e o uso de restrições para minimizar o efeito de ambiguidade rotacional e sua leitura é recomendada para aqueles que desejarem se aprofundar no tema.…”

Section: Resolução Multivariada De Curvas Com Mínimos Quadrados Alterunclassified

Experimento Didático De Quimiometria Para O Mapeamento De Pellets Farmacêuticos Utilizando Espectroscopia De Imagem Na Região Do Infravermelho Próximo E Resolução Multivariada De Curvas Com Mínimos Quadrados Alternantes: Um Tutorial, Parte Iv

2017

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A TUTORIAL, PART IV. The aim of this manuscript is to present a didactic experiment based on the combination of Near Infrared chemical imaging and Multivariate Curve Resolution for beginners, undergraduate and graduate students. In this tutorial, using MATLAB environment, the instrumental signals will be separated into two matrices, of spectral profiles and relative concentrations in the samples. Then, chemical images were generated to identify and verify the distribution of the components in the pellet samples. Chemical imaging was obtained from the mapping of predetermined area and the results for relative concentrations obtained in the ALS optimization for the analyzed area. This approach was successfully tested in chemistry undergraduate course at the Chemistry Institute of Campinas State University.

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Multivariate Curve Resolution With Alternating Least Squares: Description, Operation and Aplications

Cited by 11 publications

References 1 publication

Application of a Chemometric Method to Interpret Spectrophotometric Data Obtained for Degradation of an Organic Dye in Water Using Manganese Oxide

Application of a Chemometric Method to Interpret Spectrophotometric Data Obtained for Degradation of an Organic Dye in Water Using Manganese Oxide

Pseudo-univariate calibration as an analytical tool to determine antioxidant activity: An alternative to DPPH method applied to the evaluation from extracts of turmeric powder

Experimento Didático De Quimiometria Para O Mapeamento De Pellets Farmacêuticos Utilizando Espectroscopia De Imagem Na Região Do Infravermelho Próximo E Resolução Multivariada De Curvas Com Mínimos Quadrados Alternantes: Um Tutorial, Parte Iv

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