An inexpensive, portable and microcontrolled near infrared LED-photometer for screening analysis of gasoline

Gaião, Edvaldo da Nóbrega; Santos, Sônia Beatriz dos; Santos, Vagner Bezerra dos; Nascimento, Elaine Cristina Lima do; Lima, Renato S.; Araújo, Mário César Ugulino de

doi:10.1016/j.talanta.2007.12.014

Cited by 40 publications

(21 citation statements)

References 19 publications

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“…In this sense, inexpensive, portable and microcontroled photometers based on light emitting diodes were proposed for measurements at near-infrared 284 and visible 285 spectral regions. The infrared photometer used a LED with maximum emission at 1550 nm and a PbSe photoresistor as radiation source and detector, respectively.…”

Section: Instrumentation and Automationmentioning

confidence: 99%

Analytical chemistry in Brazil: healthy and growing

Rocha

Pereira-Filho²,

Nóbrega³

2009

J. Braz. Chem. Soc.

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A química brasileira está crescendo rapidamente, sendo um dos principais alicerces para o contínuo desenvolvimento do país. Inspirados no 15º Encontro Nacional de Química Analítica, ENQA, com um número recorde de participantes e comunicações, decidiu-se revisar os recentes desenvolvimentos em química analítica no Brasil. Foram escolhidas as mesmas áreas de aplicação adotadas para a organização temática do ENQA e selecionados artigos publicados por autores brasileiros em 7 periódicos de ampla penetração na área. Os dois periódicos científicos editados pela Sociedade Brasileira de Química também foram pesquisados. Esta revisão não é exaustiva, porém os trabalhos selecionados após 2008 mostram uma significativa visão geral da área. Pode-se concluir que a química analítica brasileira está saudável, em crescimento e certamente atenderá as demandas do país como uma potência emergida.Chemical sciences in Brazil are growing fast and being one of the main supports for the continuous development of the country. Inspired on the 15 th Brazilian Meeting on Analytical Chemistry, ENQA, with a record number of participants and communications, we have decided to review recent developments in analytical chemistry in Brazil. We have chosen the same application areas used for the thematic organization of the ENQA and have searched papers published by Brazilian authors in 7 major and general journals in analytical chemistry. The two scientific journals published by the Brazilian Chemical Society were also searched. This review is not comprehensive, but the selected papers published after 2008 shown an impressive overview of the area. We may conclude that analytical chemistry is healthy and growing in Brazilian scenario and certainly will attend the demands of Brazil as an emerged power.

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Section: Instrumentation and Automationmentioning

confidence: 99%

Analytical chemistry in Brazil: healthy and growing

Rocha

Pereira-Filho²,

Nóbrega³

2009

J. Braz. Chem. Soc.

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“…[6][7][8] However, such method presents some disadvantages, including high cost of the instrumentation, low analytical throughput, high consumption of reagents and samples and generation of harmful residues. 5,9 These limitations have motivated the development of spectrophotometric techniques for screening analysis [10][11][12][13][14][15][16][17][18][19] with the aim of reducing the number of samples that need to be analyzed by chromatographic methods. In this context, chemometrics plays a key role in the achievement of good screening results.…”

Section: Introductionmentioning

confidence: 99%

A flow-batch analyzer for UV-Vis spectrophotometric detection of adulteration in distilled spirits

Nascimento¹,

Araújo²,

Galvão³

2011

J. Braz. Chem. Soc.

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Um analisador flow-batch é proposto para detecção de adulterações em bebidas destiladas (uísque, conhaque, cachaça, rum e vodca) usando espectrofotometria UV-Vis. O analisador foi empregado para diluir as amostras não-adulteradas e para simular adulterações com adição de 5 e 10% (v/v) de água, etanol ou metanol. Modelos de classificação SIMCA (soft independent modelling of class analogies) foram construídos empregando espectros de amostras adulteradas e não-adulteradas na faixa de 235-355 nm. Aplicando-se os modelos SIMCA a um conjunto de teste, todas as amostras adulteradas e não-adulteradas foram corretamente discriminadas com um nível de confiança de 95% e uma frequência analítica superior a 120 amostras por hora.An automatic flow-batch analyzer is proposed for detection of adulteration in distilled spirits (whiskey, brandy, cachaça, rum and vodka) using UV-Vis spectrophotometry. The analyzer was employed to dilute the non-adulterated samples and to simulate adulteration with addition of 5 and 10% (v/v) of water, ethanol or methanol. SIMCA (soft independent modelling of class analogies) classification models were built using spectra of non-adulterated and adulterated samples in the region of 235-355 nm. By applying the SIMCA models to a test set, all adulterated and non-adulterated samples were correctly discriminated at a confidence level of 95% with an analytical throughput larger than 120 samples per hour.Keywords: flow-batch analyzer, SIMCA, UV-Vis spectrophotometry, adulteration of distilled spirits, screening analysis IntroductionThe adulteration of distilled spirits with water, ethanol or methanol is a problem with serious repercussions, which compromises the product quality, leads to loss of tax revenue and may constitute a public health threat. [1][2][3][4][5] In a study concerning the chemical composition of 608 beverage samples retailed in Brazil over the period [1993][1994][1995][1996][1997][1998][1999] 391 samples were found to be out of quality standards. 5 In two cases, the methanol levels were above the tolerance limit stated in Brazilian legislation. In that study, the analyses were carried out by chromatography in gaseous phase with a flame ionization detector.Chromatography is a powerful analytical method, which has been used in several works to detect adulteration in distilled spirits.6-8 However, such method presents some disadvantages, including high cost of the instrumentation, low analytical throughput, high consumption of reagents and samples and generation of harmful residues. 5,9 These limitations have motivated the development of spectrophotometric techniques for screening analysis [10][11][12][13][14][15][16][17][18][19] with the aim of reducing the number of samples that need to be analyzed by chromatographic methods. In this context, chemometrics plays a key role in the achievement of good screening results. [10][11][12] A previous work 10 proposed the use of near-infrared spectroscopy (NIR) and chemometrics to classify 69 samples of distilled spirits with respect to type (whi...

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“…Those are categorized according to the type of radiation source used (LASER, incandescent light (tungsten filament lamp) and light emitting diode (LED)), angle between the detector and the radiation source (30°, 90°, 180°, and 90° < θ < 180°) and the presence of multiples detectors (multibeams). Optical instruments based on LED as a radiation source have been described in the literature; [7][8][9][10][11][12][13][14][15][16] however, a few were dedicated to the construction of either turbidimeters or nephelometers. 12 Besides, with the use of microcontrollers, the analytical instrumentation becomes portable and presents a lower cost, lower power consumption and higher stability.…”

Section: Introductionmentioning

confidence: 99%