Development of sequential injection methodologies for the spectrophotometric direct and kinetic determination of aluminium in natural and waste waters

Abstract

Neste artigo propõem-se duas metodologias de análise por injeção seqüencial para a determinação de alumínio reativo em águas, baseadas na reação entre o "chrome azurol S" (CAS) e o alumínio. Os métodos desenvolvidos incluem uma determinação direta e uma metodologia cinética (para aplicação a águas residuais com coloração), implementadas na mesma montagem. Os intervalos dinâmicos de trabalho são: 0,040-0,500 mg Al L -1 para o método direto e 0,050-0,300 mg Al L -1 para o método cinético. O sistema descrito tem um elevado grau de automatização e permite uma freqüência de amostragem de 31 e 57 h -1 para a metodologia cinética e direta, respectivamente. O consumo de reagentes por determinação é baixo: 46 µg de CAS, 3,75 mg de acetato de sódio e 25 µg de ácido ascórbico. O volume de efluente produzido por determinação é de apenas cerca de 2,8 mL para o método direto e 3,4 mL no método cinético.Two sequential injection methodologies for the spectrophotometric determination of reactive aluminium in water samples are proposed, based on the reaction between chrome azurol S (CAS) and aluminium. The two methods involve a direct and a kinetic methodology (for its application to coloured waste waters), both accommodated within the same manifold. The working ranges obtained were: 0.040-0.500 mg Al L -1 for direct method and 0.050-0.300 mg Al L -1 for the kinetic method. The described system has high degree of automation, enabling sampling throughputs of 31 and 57 h -1 for the kinetic method and direct methods, respectively. The reagents consumption per determination is low: 46 µg of CAS, 3.75 mg of sodium acetate and 25 µg of ascorbic acid. The volume of effluent produced per determination is only around 2.8 mL in the direct method and 3.4 mL in the kinetic method.

A Green Sequential Injection Spectrophotometric Approach Using Natural Reagent Extracts from Heartwood of Ceasalpinia sappan Linn. for Determination of Aluminium

“…The relative standard deviations for eleven replicate determinations of 0.1 and 0.25 mg L -1 were 3.2 and 2.4%, respectively. A comparable analytical performance of the proposed method with other flowbased methods for the spectrophotometric determination of aluminium, using various synthetic dyes, such as chrome azurol S (CAS), 11,32,33 eriochrome cyanine R (ECR), 34,35 and quercetin 36 was obtained, although, the developed method used only natural dye as a chromogenic reagent. In addition, the developed method provided a higher sensitivity than the previous flowbased methods using other natural reagents such as Morinda citrifolia root extract, 24 and Terminalia catappa L. leaf extract.…”

To the question about the definition of a stationary temperature field in the capillary during the passage of electric current and the change in water concentration of impurities in the temperature field

“…В этих случаях, как правило, речь идет о проточных методах анализа off-line водных вытяжек из соответствующих объектов, полученных в независимом эксперименте [2]. Наиболее часто применяемыми методами детектирования в проточном анализе объектов окружающей среды являются спектрофотометрия [95,96], флуориметрия [97,98] и ИК-спектроскопия [68], позволяющие обеспечить простое, надежное, чувствительное, а в некоторых случаях и достаточно селективное определение аналитов. Также широко используются электрохимические методы детектирования: потенциометрия [99,100] и вольтамперометрия [101], основными преимуществами которых являются простота и портативность детекторов и обеспечение возможности выполнения анализов в широком диапазоне концентраций.…”

A sensitive flow-injection analysis method with iminodiacetate chelation and spectrophotometric detection for on board determination of trace dissolved aluminum in seawater

“…Because of the automaticity, preciseness, robustness, simplicity and low risk of contamination, ow injection analysis (FIA) is widely used for the determination of trace metals and nutrients. [27][28][29] By coupling spectrophotometry and an SPE technique, FIA has become a widespread method for the long term on-line monitoring of trace metals (Fe, Mn, Al). 14,30,31 In our work, a exible FIA method with an SPE technique based on a classic spectrophotometric method has been developed for the determination of trace dAl in seawater.…”