Light emitting diode based flow-through optical absorption detectors

Dasgupta, Purnendu Κ.; Bellamy, Harvey S.; Liu, Hanghui; López, Jorge L.; Loree, Ellis L.; Morris, Kavin J.; Petersen, Kaj; Mir, Kalam A.

doi:10.1016/0039-9140(93)80142-e

Cited by 113 publications

(69 citation statements)

References 29 publications

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“…6 Light emitting diodes (LEDs) have become increasingly popular as light sources in separation systems [7][8][9][10] due to their advantageous characteristics such as low power consumption, low cost, increasing spectral range coverage (247 nm -1550 nm 11,12 ), size, intensity and efficiency. [13][14][15] Previously we demonstrated the use of a paired emitter-detector diode (PEDD) system as a highly sensitive photometric detector in liquid chromatography. 7 The PEDD employs two LEDs, whereby one serves as the light source and the second LED in reverse bias mode is employed as the light detector.…”

Section: Introductionmentioning

confidence: 99%

Paired emitter–detector diode detection with dual wavelength monitoring for enhanced sensitivity to transition metals in ion chromatography with post-column reaction

Toole

Barron

Shepherd

et al. 2009

Analyst

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Section: Introductionmentioning

confidence: 99%

Paired emitter–detector diode detection with dual wavelength monitoring for enhanced sensitivity to transition metals in ion chromatography with post-column reaction

Toole

Barron

Shepherd

et al. 2009

Analyst

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show abstract

Section: Introductionmentioning

confidence: 99%

“…LEDs are widely exploited in the development of analytical instrumentation because of the high stability, low power consumption, and low-cost. 9 Since LEDs emit radiation in a fairly narrow band with half maximum intensity generally in the range of 20-50 nm and they have a large variety of wavelength available. LED-based analytical equipment generally do not require sophisticated optical devices such as interference filters, monochromators, lenses, mirrors, and rifts.…”

Section: Introductionmentioning

confidence: 99%

“…LED-based analytical equipment generally do not require sophisticated optical devices such as interference filters, monochromators, lenses, mirrors, and rifts. 1,3,9,10 Photodiodes are photodetectors that have been successfully applied in the development of optical instrumentation because of their high sensitivity, good linearity, fast response, ease of amplification, low cost, and small dimensions. 3,4,11,12 When the radiation is incident on the photodiode, an electric current is produced and it can be proportionally converted to voltage and measured using, for example, a microcontroller as the specific data interface.…”

Section: Introductionmentioning

confidence: 99%

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A Low-Cost Portable Microcontrolled Nephelometer for Potassium Determination

Santos¹,

Guerreiro²,

Suarez³

et al. 2011

J. Braz. Chem. Soc.

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Um nefelômetro microcontrolado portátil e de baixo custo é proposto para a determinação de potássio em água de coco e bebidas energéticas. O nefelômetro foi construído utilizando dois LEDs (diodos emissores de luz) como fontes de radiação em 465 nm e 880 nm, dois fotodiodos como fotodetectores e um controlador de interface periférica (PIC) para aquisição e processamento dos dados. O nefelômetro foi utilizado para determinar íons potássio pelo monitoramento do precipitado formado na reação entre íons K + e tetrafenilborato em meio básico na presença de álcool polivinílico. A curva analítica foi linear para potássio na faixa de concentração de 5,0×10 −6 a 5,0×10 −4 mol L −1 , com um limite de detecção de 4,0×10 −7 mol L −1 . Um desvio padrão relativo de 0,2 % para uma solução de potássio 1,6×10 −4 mol L −1 (n = 10) foi obtido. Respostas rápidas e confiáveis e baixo consumo de energia são outras características do nefelômetro proposto.A low-cost portable microcontrolled nephelometer for the determination of potassium in coconut water and energy beverages is proposed. The nephelometer was constructed using two LEDs (light emitting diodes) as radiation sources at 465 nm and 880 nm, two photodiodes as photodetectors, and a peripheral interface controller (PIC) to acquisition and processing data of the nephelometer. The nephelometer was used to determine potassium ions by monitoring the precipitate formed from the reaction between K + and tetraphenylborate anion in a basic medium in the presence of polyvinyl alcohol. The analytical curve was linear in the potassium concentration range from 5.0×10 −6 to 5.0×10 −4 mol L −1 , with a limit of detection of 4.0×10 −7 mol L −1 . A relative standard deviation of 0.2 % for 1.6 × 10 −4 mol L −1 potassium solution (n = 10) was obtained. Fast and reliable responses, low power consumption are other attractive features of the proposed nephelometer.Keywords: microcontroller, nephelometer, light emitting diode, analytical instrumentation, sodium tetraphenylborate IntroductionA nephelometer measures the turbidity of a solution containing suspended particles by directing a beam of light into the sample and sensing the light scattered, usually at right angles (at a 90° angle with respect to the light beam). [1][2][3] This technique has been applied to determine sulfate in water, 4 aqueous drug solubility, 5 and for immunoassays such as of proteins in maternal milk, 6 cystatin-C in serum, 7 and serum myoglobin in patients with acute pancreatitis. 8 Generally, spectrofluorimeters and fluorimeters are analytical instruments widely applied for this purpose. However, components such as high-intensity radiation sources, sophisticated detectors and wavelength selectors, and other optical devices make such equipments expensive. 1,3 Furthermore, these types of equipment are not portable and need microcomputers for control and data acquisition.LEDs (light emitting diodes) are semiconductor devices with p-n junction that exhibit electroluminescence properties when a current passes through them. LED...

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“…Nevertheless, depending on the LED type, the width of the emission band can range from 30 to 100 nm [10][11][12][13]. However, by carefully selecting the methods, LEDs can became a good option as a radiation source in flow system when multidetermination is performed with photometric detection employing non-expensive instrumentation [14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Automatic flow system for simultaneous determination of iron and chromium in steel alloys employing photometers based on LEDs as radiation source

Fernandes¹,

Reis²,

Campos³

2003

Journal of Automated Methods & Management in Chemistry

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A multicommutated flow system for simultaneous determination of iron and chromium in steel alloys by photometry is described. The flow network consisted of an automatic injector and four solenoid valves assembled to form two independent analytical pathways, each one comprising reaction coils and a flow cell. The light source (LED) and detector (photodiode) were attached to the flow cells to form a compact unit. The flow system was microcomputer controlled by Quick BASIC 4.5 software, which carried out all steps of the analytical procedure. The feasibility of the system was proved by the determination of iron and chromium in steel alloys and its accuracy was accessed by comparing results with those obtained by plasma atomic emission spectrometry (ICP-AES). No significant difference at the 95% confidence level was observed.Other profitable features such as low reagent consumption (0.33 mg 1,10-phenantroline and 0.03 mg 1,5-diphenylcarbazide per determination); relative standard deviations (n ¼ 5) of 0.4% for iron and 1.2% for chromium; and an analytical throughput of 160 determinations per h were also achieved.

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Light emitting diode based flow-through optical absorption detectors

Cited by 113 publications

References 29 publications

Paired emitter–detector diode detection with dual wavelength monitoring for enhanced sensitivity to transition metals in ion chromatography with post-column reaction

Paired emitter–detector diode detection with dual wavelength monitoring for enhanced sensitivity to transition metals in ion chromatography with post-column reaction

A Low-Cost Portable Microcontrolled Nephelometer for Potassium Determination

Automatic flow system for simultaneous determination of iron and chromium in steel alloys employing photometers based on LEDs as radiation source

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