Speciation of chromium in natural waters by micropumping multicommutated light emitting diode photometry

Pires, Cherrine K.; Reis, Boaventura F.; Morales‐Rubio, Ángel; Guárdia, Miguel de la

doi:10.1016/j.talanta.2007.01.044

Cited by 28 publications

(15 citation statements)

References 22 publications

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“…Many reliable methods about Cr speciation that propose alternatives offering low-cost, high sensitivity and waste reduction are observed in the literature [12][13][14][15][16]. Digital image analyses are found for analytical methods in different matrices [17][18][19][20][21][22][23][24][25][26][27][28][29][30] and also for environmental monitoring and remote sensing [31,32].…”

Section: Introductionmentioning

confidence: 99%

Proposition of a simple method for chromium (VI) determination in soils from remote places applying digital images: A case study from Brazilian Antarctic Station

Oliveira

Canevari

Guerra

et al. 2013

Microchemical Journal

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In this study, we proposed a straightforward approach that could be used for Cr redox speciation in soil samples from remote places. For this aim, soil samples under strong anthropogenic impact, from the vicinity of the Brazilian Antarctic Station were studied. Control samples with no direct impact, were also collected further (4 km) from the station. A preliminary laboratory evaluation for Cr (VI) presence was performed using X-ray absorption spectroscopy. The proposed method was based on a hot alkaline extraction to promote the quantitative extraction of Cr (VI) from soil samples. The colorimetric reagent 1,5-diphenylcarbazide (DPC) was added to the extracts to form a violet complex with Cr (VI). A simple and inexpensive commercial scanner was used to acquire the digital images of the formed complex. Partial Least Squares models were constructed with the following average color descriptors: red (R), green (G), blue (B), hue (H), saturation (S), value (V), relative color descriptors (r, g and b) and luminosity (L). The results obtained with this scanner approach were consistent with the official method that uses a spectrophotometer at 540 nm. Besides that, this is the first study that reports Cr redox speciation in soils from Antarctica, which is regarded as the less polluted place on the Earth.

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Section: Introductionmentioning

confidence: 99%

Proposition of a simple method for chromium (VI) determination in soils from remote places applying digital images: A case study from Brazilian Antarctic Station

Oliveira

Canevari

Guerra

et al. 2013

Microchemical Journal

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“…The flow system showed in Figure 1 comprised seven solenoid micro-pumps, from Bio-Chem Valve, 090SP (Boonton, USA); a microcomputer equipped with an electronic interface card Advantech, PCL-711S (San Jose, CA, USA); a homemade electronic interface to drive the micro-pumps similar to that described elsewhere; 21 a homemade LED-based photometer, 22 equipped with a flow cell with 100 mm optical pathlength and 2.0 mm inner diameter and a LED with an emission wavelength of 530 nm; reaction coils and flow lines made of PTFE tubing (0.8 mm i.d.) and home-made confluence connectors.…”

Section: Apparatusmentioning

confidence: 99%

Multi-pumping mechanised determination of selenium in natural waters by light emitting diode (LED) spectrometry

Fernandes¹,

Reis²,

Morales‐Rubio³

et al. 2009

J. Braz. Chem. Soc.

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Um procedimento para determinação de selênio em águas, completamente mecanizado, foi desenvolvido empregando um fotômetro baseado em LED e mini-bombas solenóide como dispositivos de propulsão. O método proposto é baseado na reação de selênio com iodeto de potássio em meio ácido para liberar iodo, o qual oxida a variamina azul formando um composto violeta que absorve em 530 nm. O sistema foi mecanizado empregando o processo de multicomutação em fluxo e uma estratégia de parada de fluxo na etapa final para desenvolvimento da reação. A curva analítica foi linear entre as concentrações de 0,010 a 0,500 mg L , respectivamente. A freqüência de amostragem foi de 23 determinações por hora, e a exatidão foi de 95% de probabilidade.It has been developed a fully mechanised procedure for the determination of selenium in waters employing a LED based spectrometer and solenoid multi-pumps as solution propelling devices. The proposed method is based on the reaction of selenium with potassium iodide in an acidic medium to liberate iodine, which oxidizes Variamine Blue to form a violet-colour species which absorb at 530 nm. The system was mechanised using the multicommutation process and a stopped flow strategy in the final step reaction. The analytical curve was linear between 0.010 and 0.500 mg L . The relative standard deviation for Se solutions of 0.050 and 0.200 mg L -1 (n = 4) were 1.6 and 1.8% respectively, the sampling throughput was 23 determinations per hour, and accuracy was 95% probability level.

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“…The availability of LED that emit highly intense radiation beam has allowed the use of flow cells with an optical path length of 100 mm, which has been exploited for developing highly sensitive photometric analytical procedures for chromium speciation and N -ureide determination in soybean tissues [20, 21]. …”

Section: Introductionmentioning

confidence: 99%

A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step

Santos

Reis

2017

Journal of Analytical Methods in Chemistry

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A highly sensitive analytical procedure for photometric determination of molybdenum in plant materials was developed and validated. This procedure is based on the reaction of Mo(V) with thiocyanate ions (SCN−) in acidic medium to form a compound that can be monitored at 474 nm and was implemented employing a multicommuted flow analysis setup. Photometric detection was performed using an LED-based photometer coupled to a flow cell with a long optical path length (200 mm) to achieve high sensitivity, allowing Mo(V) determination at a level of μg L−1 without the use of an organic solvent extraction step. After optimization of operational conditions, samples of digested plant materials were analyzed employing the proposed procedure. The accuracy was assessed by comparing the obtained results with those of a reference method, with an agreement observed at 95% confidence level. In addition, a detection limit of 9.1 μg L−1, a linear response (r = 0.9969) over the concentration range of 50–500 μg L−1, generation of only 3.75 mL of waste per determination, and a sampling rate of 51 determinations per hour were achieved.

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Speciation of chromium in natural waters by micropumping multicommutated light emitting diode photometry

Cited by 28 publications

References 22 publications

Proposition of a simple method for chromium (VI) determination in soils from remote places applying digital images: A case study from Brazilian Antarctic Station

Proposition of a simple method for chromium (VI) determination in soils from remote places applying digital images: A case study from Brazilian Antarctic Station

Multi-pumping mechanised determination of selenium in natural waters by light emitting diode (LED) spectrometry

A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step

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