Derivative ultraviolet—visible region absorption spectrophotometry and its analytical applications

Rojas, F. Sánchez; Ojeda, C. Bosch; Pavón, José Manuel Cano

doi:10.1016/0039-9140(88)80179-6

Cited by 136 publications

(36 citation statements)

References 75 publications

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“…18,19) In this paper we examined the effect of PS content on the partition coefficients of the benzodiazepin drugs, diazepam (DZ) and flurazepam (FZ), between PC-PS bilayer membranes of small unilamellar vesicles (SUV) by using second derivative spectrophotometry.…”

mentioning

confidence: 99%

Effect of Phosphatidylserine Content on the Partition Coefficients of Diazepam and Flurazepam between Phosphatidylcholine-Phosphatidylserine Bilayer of Small Unilamellar Vesicles and Water Studied by Second Derivative Spectrophotometry.

Omran

Kitamura

Takegami

et al. 2002

CHEMICAL & PHARMACEUTICAL BULLETIN

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mentioning

confidence: 99%

Effect of Phosphatidylserine Content on the Partition Coefficients of Diazepam and Flurazepam between Phosphatidylcholine-Phosphatidylserine Bilayer of Small Unilamellar Vesicles and Water Studied by Second Derivative Spectrophotometry.

Omran

Kitamura

Takegami

et al. 2002

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…To perform derivative calculation via numerical differentiation, noise reduction should usually be performed. A differentiated signal has the following properties: peak maxima or minima give extrema in even derivatives and zero crossing in odd derivatives; inflection points give zero crossing in even derivatives and extrema in odd derivatives; as the derivative order increases, the number of extrema exceeds that of the input curve because each inflection gives an additional extreme by differentiation; as the derivative order increases, the width at half-height becomes smaller and the peak becomes sharper; the signal-tonoise ratio depends on the width or the number of points in the fwhm of the peak [127]. Commonly used methods of differentiation are Savitzky-Golay, ADPF, splines and WT.…”

Section: Separation Of Overlapping Signalsmentioning

confidence: 99%

“…The up-to-date review of the application of multivariate methods in the treatment of multicomponent overlapping signals are presented in [15]. Differentiation is one of the methods for increasing the information content of the analytical signal [127]. Derivatives are useful in processing poorly pronounced signals of low concentration.…”

Section: Separation Of Overlapping Signalsmentioning

confidence: 99%

Signal Processing in Electrochemistry

Jakubowska

2011

Electroanalysis

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This review presents and promotes preprocessing methods applied in electrochemistry prior to data exploration, calibration and classification. Smoothing by digital filtering, baseline correction, separation of overlapping signals, and also transformations to extract the relevant features of the curve are the algorithms of which the application, operation, and optimization of parameters are described. The presentation completes the description of the procedure enabling orthogonal correction of the signals. The theoretical consideration is demonstrated by examples of the practical application of the described algorithms in electrochemistry in recent years. Software packages useful in signal processing in electrochemistry are also listed. The paper underlines the point that particular methods show the different effects of signal processing and in the case of the improper selection of the algorithm or its parameters, undesirable distortions of the curves may be observed. Therefore a knowledge of signal processing methodology is necessary before its application.

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“…O aumento de sensibilidade observado na espectrometria derivativa é baseado na observação de que a amplitude da derivada n da absorvância em relação ao comprimento de onda (D n = d n A/dλ) é inversamente proporcional à largura de banda do espectro ordinário (W) 28,32 :…”

Section: Espectrofotometria Derivativaunclassified

Estratégias para aumento de sensibilidade em espectrofotometria UV-VIS

Rocha¹,

Teixeira²

2004

Quím. Nova

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Recebido em 6/5/03;aceito em 19/2/04; publicado na web em 17/6/04 STRATEGIES TO INCREASE SENSITIVITY IN UV-VIS SPECTROPHOTOMETRY. Spectrophotometry is one of the most widespread analytical techniques due to its simplicity, reliability, and low-cost instrumentation for both direct measurements and coupled to other techniques or processes such as chromatography, electrophoresis and flow analysis. However, the application is often limited by sensitivity. This article describes some advances that greatly improve the performance of spectrophotometric measurements, especially in order to increase sensitivity, including the employment of liquid-core waveguides and solid-phase spectrophotometry.Keywords: UV-VIS spectrophotometry; long-pathlength spectrophotometry; solid-phase spectrophotometry. INTRODUÇÃOEspectrofotometria na região UV-VIS do espectro eletromagnéti-co é uma das técnicas analíticas mais empregadas, em função de robustez, custo relativamente baixo e grande número de aplicações desenvolvidas 1 . Consultando-se o banco de dados do "Analytical Abstracts", verifica-se ca. 40000 ocorrências relacionadas à espectrofotometria 2 . Os procedimentos envolvem medidas diretas de espécies que absorvem radiação, medidas após derivação química e acoplamento a diversas técnicas ou processos, como cromatografia, eletroforese e análises em fluxo. Além disso, constitui-se em uma importante ferramenta para determinação de parâmetros fisico-quími-cos, tais como constantes de equilíbrio e de velocidade de reações.Apesar da extensa utilização, várias inovações recentes relacionadas às medidas espectrofotométricas ainda são pouco conhecidas. Com respeito ao aspecto instrumental, é notável a evolução desde os procedimentos baseados em comparações visuais e dos fotômetros empregando filtros para a seleção de comprimentos de onda até os equipamentos mais recentes, que empregam arranjos de fotodetectores. Esses permitem a aquisição de espectros de absorção em intervalos de tempo da ordem de milésimos de segundos e são disponíveis, inclusive, em versões miniaturizadas acopladas a computadores do tipo "palm-top" 3 . A espectrofotometria é fundamentada na lei de Lambert-Beer, que é a base matemática para medidas de absorção de radiação por amostras no estado sólido, líquido ou gasoso, nas regiões ultravioleta, visível e infravermelho do espectro eletromagnético. Para medidas de absorção de radiação em determinado comprimento de onda, temse: A= log(I o /I) = ε ε ε ε εbc, onde A é a absorvância, I o é a intensidade da radiação monocromática que incide na amostra e I é a intensidade da radiação que emerge da amostra. A absortividade molar (ε) é uma grandeza característica da espécie absorvente, cuja magnitude depende do comprimento de onda da radiação incidente. O termo c é a concentração da espécie absorvente e b, a distância percorrida pelo feixe através da amostra 4 . Muitas das inovações referentes à espectrofotometria consistem em estratégias para aumento de sensibilidade, visando ampliação da faixa de aplicação da técnica e permitin...

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Derivative ultraviolet—visible region absorption spectrophotometry and its analytical applications

Cited by 136 publications

References 75 publications

Effect of Phosphatidylserine Content on the Partition Coefficients of Diazepam and Flurazepam between Phosphatidylcholine-Phosphatidylserine Bilayer of Small Unilamellar Vesicles and Water Studied by Second Derivative Spectrophotometry.

Effect of Phosphatidylserine Content on the Partition Coefficients of Diazepam and Flurazepam between Phosphatidylcholine-Phosphatidylserine Bilayer of Small Unilamellar Vesicles and Water Studied by Second Derivative Spectrophotometry.

Signal Processing in Electrochemistry

Estratégias para aumento de sensibilidade em espectrofotometria UV-VIS

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