Multivariate optimisation of the experimental conditions for determination of three methylxanthines by reversed-phase high-performance liquid chromatography

Aragão, Nádia Machado de; Veloso, Márcia C. C.; Bispo, Márcia Souza; Ferreira, Sérgio Luís Costa; Andrade, Jailson B. de

doi:10.1016/j.talanta.2005.04.066

Cited by 54 publications

(22 citation statements)

References 18 publications

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“…Optimization of the chromatographic conditions may be carried out by a traditional univariate approach, in which each factor is studied separately, or by multivariate experimental design strategy, which allows for simultaneous variation of all evaluated factors, making it possible to distinguish interactions among them that would not be detectable by classical univariate experimental design [21,22]. Multivariate optimization design also allows a reduction in the number of required experiments, without loss of information.…”

Section: Introductionmentioning

confidence: 99%

Multivariate optimization of a GC–MS method for determination of sixteen priority polycyclic aromatic hydrocarbons in environmental samples

Lopes

Rocha

Pereira

et al. 2008

J of Separation Science

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This paper describes the development and optimization, by using multivariate analysis, of a GC -MS-SIM method for evaluation of the 16 polyaromatic hydrocarbons considered as priority pollutants in atmospheric particulate material by the US EPA. In order to assure an adequate separation in the shortest analysis time, a multivariate design was used to set the conditions of the oven temperature program. The optimization process was carried out using factorial fractional design and BoxBehnken design. The following factors were evaluated: initial temperature, temperature rate #1, intermediary temperature, temperature rate #2, and final temperature. The optimized conditions were set at: 708C (2 min) 2008C (308C/min, 5 min) 3008C (58C/min, 1.67 min). Moreover, we have also optimized the injector temperature as 3108C and sampling time as 0.8 min. The total analysis time was 33 min. Validation of GC -MS-SIM yielded satisfactory results for repetitivity of the detector response and retention times, and linearity of calibration curves. LOD were established as 0.13 -0.34 ng/mL (peak area) and 0.18 -0.72 ng/mL (peak height). The method has been shown to be appropriate for the analysis of samples of atmospheric particulate material and/or other environmental matrices.

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Section: Introductionmentioning

confidence: 99%

Multivariate optimization of a GC–MS method for determination of sixteen priority polycyclic aromatic hydrocarbons in environmental samples

Lopes

Rocha

Pereira

et al. 2008

J of Separation Science

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“…O pH da fase móvel deve ser abaixo da constante de ionização, pois o aumento da forma ionizada do analito aumenta sua dissolução na fase aquosa e reduz seu tempo de retenção, já que a forma iônica passa através da coluna sem retenção (Ivanovic et al, 1995). O tamponamento é feito visando evitar variações de pH, visto que quando as metilxantinas e catequinas são expostas a pH superiores a 4,0 são protonadas e assim, não interagem com a fase estacionária, sendo eluídas sem sofrer detecção (Aragão et al, 2005).…”

Section: Resultsunclassified

Determinação de taninos e metilxantinas no guaraná em pó (Paullinia cupana Kunth, Sapindaceae) por cromatografia líquida de alta eficiência

Sousa¹,

Alves²,

Paula³

et al. 2010

Rev. bras. farmacogn.

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RESUMO:As sementes de guaraná (Paullinia cupana Kunth, Sapindaceae) são utilizadas como estimulante e os principais constituintes químicos são as metilxantinas e os taninos, tais como catequina e epicatequina. Este trabalho teve por objetivo investigar um método por cromatografia líquida de alta eficiência (CLAE) para quantificar, simultaneamente, cafeína, teofilina, teobromina, catequina e epicatequina em pó de guaraná. Os valores obtidos foram comparados com os resultados encontrados no método espectrofotométrico da Farmacopéia Brasileira IV ed. Pelo método cromatográfico, os teores de metilxantinas e taninos totais foram de 4,04% e 1,48%, respectivamente. Os teores de metilxantinas e taninos totais, obtidos pelo método espectrofotométrico, foram de 4,88% e 4,05%, respectivamente. Acredita-se que, nas condições experimentais empregadas, o método espectrofotométrico não foi específico, quantificando outras substâncias fenólicas presentes no guaraná. Portanto, sugere-se o emprego desse método cromatográfico no controle de qualidade do guaraná em pó, por ser preciso, sensível, específico e rápido. Unitermos:Controle de qualidade, planta medicinal, guaraná, cafeína, catequina, CLAE.ABSTRACT: "Determination of tannins and methylxanthines in powdered guarana (Paullinia cupana Kunth, Sapindaceae) by high performance liquid chromatography". The seeds of Paullinia cupana Kunth, Sapindaceae, are used as a stimulant and the main chemical constituents are the methylxanthines and tannins, as catechin and epicatechin. This study aimed to investigate a method by high performance liquid chromatography (HPLC) to quantify both caffeine, theophylline, theobromine, catechin and epicatechin in powdered of P. cupana. The values obtained were compared with the results of the spectrophotometric method of the Brazilian Pharmacopoeia IV ed. For the chromatographic method, the levels of methylxanthines and total tannins were 4.04% and 1.48%, respectively. The levels of methylxanthines and total tannins obtained by the spectrophotometric method, were 4.88% and 4.05%, respectively. It is believed that, under our experimental conditions, the spectrophotometric method was not specific and quantified others phenolic substances present in the P. cupana. Therefore we suggest the use of this chromatographic method in quality control of P. cupana powder, to be accurate, sensitive, specific and fast. INTRODUÇÃOO guaraná, Paullinia cupana Kunth é uma planta da família Sapindaceae, originária da região Amazônica, a qual possui clima tropical, quente e úmido. É amplamente utilizado na medicina tradicional brasileira, sendo empregada em bebidas caseiras e industriais, como tônico e estimulante. A parte utilizada é a semente seca e

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“…In the Brazilian Pharmacopoeia 5 , AntoneliUshirobira et al, 1 , Pelozo et al, 15 and Sousa et al, 2 describe methods using UV spectroscopy to quantify methylxanthines and UV-Vis spectroscopy to quantify tannins. We also found several quantification methods using high performance liquid chromatography (HPLC) 1,2,4,7,16,17 . However, this technique requires expensive equipment and has a high cost of maintenance and operation 17 .…”

Section: Fig 1: Chemical Structure Of (A) Caffeine (Caf) and (B) Catmentioning

confidence: 99%

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2016

IJPSR

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ABSTRACT:A method using derivative UV spectrophotometry was developed and validated for the determination of methylxanthines and tannins in guarana bulk, using caffeine and catechin as markers. The spectra were obtained using first order derivatization, Δλ=20.000, and scale factor of 10. The quantification of actives was performed using wavelengths of 244 and 277 nm for catechin and caffeine, respectively. The parameters of specificity, linearity, precision, accuracy, robustness, limits of detection (LOD) and quantification (LOQ) were established to validate the method. The method was shown to be specific for quantification of methylxanthines and tannins, and linear over the concentration range 5-35 µg mL -1 , with a correlation coefficient of r=1(caffeine) and r=0.9993 (catechin). The results indicated good intra-day and inter-day precision with RSDs less than 2%. The method was accurate, exhibiting recoveries between 98 and 102%. The LODs were 0.184 µg mL -1 (caffeine) and 0.368 µg mL -1 (catechin), and the LOQs were 0.552 µg mL -1 (caffeine) and 1.104 µg mL -1 (catechin). Methylxanthines and tannins were quantified, and contents of 10 µg mL -1 and 20 µg mL -1 , respectively, were observed.

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Multivariate optimisation of the experimental conditions for determination of three methylxanthines by reversed-phase high-performance liquid chromatography

Cited by 54 publications

References 18 publications

Multivariate optimization of a GC–MS method for determination of sixteen priority polycyclic aromatic hydrocarbons in environmental samples

Multivariate optimization of a GC–MS method for determination of sixteen priority polycyclic aromatic hydrocarbons in environmental samples

Determinação de taninos e metilxantinas no guaraná em pó (Paullinia cupana Kunth, Sapindaceae) por cromatografia líquida de alta eficiência

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