An automated flow-injection titrator for spectrophotometric determinations of total acidity in wines, using a single standard solution and gradient calibration

Gaião, Edvaldo N.; Honorato, Ricardo S.; Santos, Sônia Beatriz dos; Araújo, Mário César Ugulino de

doi:10.1039/a905188k

Cited by 28 publications

(12 citation statements)

References 27 publications

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“…De fato, fotômetros simples, portáteis e de baixo custo, que empregam LED como fonte de radiação, têm sido desenvolvidos e usados em diversas aplicações analíticas [1][2][3][4][5][6][7] . Entre os fotômetros descritos na literatura, existem alguns que usam dois ou mais LEDs com máximos de emissão em diferentes comprimentos de onda, o que os tornam potencialmente aplicáveis a análises multicomponentes 2,8 .…”

Section: Diodos Emissores De Luz (Leds)unclassified

Um fotômetro multi-led microcontrolado, portátil e de baixo custo

Gaião¹,

Medeiros²,

Lyra³

et al. 2005

Quím. Nova

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Section: Diodos Emissores De Luz (Leds)unclassified

Um fotômetro multi-led microcontrolado, portátil e de baixo custo

Gaião¹,

Medeiros²,

Lyra³

et al. 2005

Quím. Nova

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“…They are also endowed with high sample throughput (10-60 h−1) and capability for automation, thus making them suitable for winery requirements. Continuous methods for determination of total acidity in wines Gaiao et al, 1999;Rangel and Toth, 1998) without separation steps use photometric detection and acid-base colored indicators. These methods are simple, fast, accurate, and precise enough (average RSD < 5%) to accomplish OIV requirements.…”

Section: Continuous Methodsmentioning

confidence: 99%

Analytical Methods in Wineries: Is It Time to Change?

Castro

Pérez-Juan²

2005

Food Reviews International

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A review of the methods for the most common parameters determined in wine-namely, ethanol, sulfur dioxide, reducing sugars, polyphenols, organic acids, total and volatile acidity, iron, soluble solids, pH, and color-reported in the last 10 years is presented here. The definition of the given parameter, official and usual methods in wineries appear at the beginning of each section, followed by the methods reported in the last decade divided into discontinuous and continuous methods, the latter also are grouped in nonchromatographic and chromatographic methods because of the typical characteristics of each subgroup. A critical comparison between continuous and discontinuous methods for the given parameter ends each section. Tables summarizing the features of the methods and a conclusions section may help users to select the most appropriate method and also to know the state-of-the-art of analytical methods in this area. Keywords Parameters, Official methods, Usual methods, Non chromatographic methods, Chromatographic methodsWine is a product with a very complex composition. Among the large number of substances found in wine, many are at very low concentrations even though they play a main role in wine characteristics, evolution, and/or quality. A complete analysis of wine is a time-consuming process, but it yields the necessary information for both elaboration of a quality product and conservation under proper conditions. Usually, the number of parameters to be analyzed is simplified as a function of the aim, the commonest being either to know the evolution of the process or to fulfill food laws. The more detailed the analysis is, the better knowledge of the wine is achieved, but a compromise between time and information requirements must be established in order to guarantee a given quality with minimum cost. Therefore, only a few parameters are periodically checked. Between them, the most common are: soluble solids, reducing sugars, alcoholic degree, pH, total and volatile acidity, sulfur dioxide, color, polyphenol index, iron, and organic acids.Most analytical methods for monitoring wine composition recognized by the international community as official methods of analysis are manual methods with high robustness and precision, even though more recent methods may be based on modern automated instrumental techniques. Nevertheless, the manual methods are slow, tedious, and require a high level of human participation. Thus, their application is a balance between the number of parameters required for monitoring wine production, frequency of analysis, and cost of human and material resources. The new faster methods, which usually have the appropriate sensitivity, selectivity, and precision, can circumvent the problem created by the large number of samples to be analyzed in order to guarantee proper monitoring of wine production. In the last 10 years, rapid and high sample throughput methods of analysis have been developed. It is interesting to know the features of these new methods-mainly in terms of accuracy and preci...

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“…They are available in a large variety of wavelengths in the visible and near UV spectrum with a long lifetime, providing simple and inexpensive devices for photometric measurements. In the last decades, LEDs [1] have been used mainly for absorbance [2][3][4][5][6][7][8][9] and fluorescence [10,11] measurements. LEDs have been also employed in polarimetry [12], liquid-chromatography, and capillary electrophoresis [13].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of a Multicommuted Flow System for PhotometricEnvironmental Measurements

Ródenas‐Torralba

Rocha

Reis

et al. 2006

Journal of Analytical Methods in Chemistry

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A portable flow analysis instrument is described for in situ photometric measurements. This system is based on light-emitting diodes (LEDs) and a photodiode detector, coupled to a multipumping flow system. The whole equipment presents dimensions of 25 cm × 22 cm × 10 cm, weighs circa 3 kg, and costs 650 €. System performance was evaluated for different chemistries without changing hardware configuration for determinations of (i) Fe3+ with SCN-, (ii) iodometric nitrite determination, (iii) phenol with sodium nitroprusside, and (iv) 1-naphthol-N-methylcarbamate (carbaryl) with p-aminophenol. The detection limits were estimated as 22, 60, 25, and 60 ng mL -1 for iron, nitrite, phenol, and carbaryl at the 99.7% confidence level with RSD of 2.3, 1.0, 1.8, and 0.8%, respectively. Reagent and waste volumes were lower than those obtained by flow systems with continuous reagent addition. Sampling rates of 100, 110, 65, and 72 determinations per hour were achieved for iron, nitrite, phenol, and carbaryl determinations

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An automated flow-injection titrator for spectrophotometric determinations of total acidity in wines, using a single standard solution and gradient calibration

Cited by 28 publications

References 27 publications

Um fotômetro multi-led microcontrolado, portátil e de baixo custo

Um fotômetro multi-led microcontrolado, portátil e de baixo custo

Analytical Methods in Wineries: Is It Time to Change?

Evaluation of a Multicommuted Flow System for PhotometricEnvironmental Measurements

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