A photometric detector based on a blue light-emitting diode

Hauser, Peter C.; Chiang, David W.L.

doi:10.1016/0039-9140(93)80187-v

Cited by 25 publications

(10 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…LEDs are well known for their batch consistency, reliability and stability and therefore are recognized as valuable light source for analytical chemistry application 10. After the visionary LED‐oximeter by Cohen and Wadswort in 1972 11 and some early pioneering research reports from 1980s to early 1990s, the use of LEDs started to grow exponentially 12–24. The use of LEDs as quasi‐monochromatic light sources for fluorometry and photometry has been well established and steadily growing from the 1990s and is well documented 10, 25–27.…”

Section: Introductionmentioning

confidence: 99%

White LEDs as broad spectrum light sources for spectrophotometry: Demonstration in the visible spectrum range in a diode‐array spectrophotometric detector

2010

View full text Add to dashboard Cite

Although traditional lamps, such as deuterium lamps, are suitable for bench-top instrumentation, their compatibility with the requirements of modern miniaturized instrumentation is limited. This study investigates the option of utilizing solid-state light source technology, namely white LEDs, as a broad band spectrum source for spectrophotometry. Several white light LEDs of both RGB and white phosphorus have been characterized in terms of their emission spectra and energy output and a white phosphorus Luxeon LED was then chosen for demonstration as a light source for visible-spectrum spectrophotometry conducted in CE. The Luxeon LED was fixed onto the base of a dismounted deuterium (D(2) ) lamp so that the light-emitting spot was geometrically positioned exactly where the light-emitting spot of the original D(2) lamp is placed. In this manner, the detector of a commercial CE instrument equipped with a DAD was not modified in any way. As the detector hardware and electronics remained the same, the change of the deuterium lamp for the Luxeon white LED allowed a direct comparison of their performances. Several anionic dyes as model analytes with absorption maxima between 450 and 600 nm were separated by CE in an electrolyte of 0.01 mol/L sodium tetraborate. The absorbance baseline noise as the key parameter was 5 × lower for the white LED lamp, showing clearly superior performance to the deuterium lamp in the available, i.e. visible part of the spectrum.

show abstract

Section: Introductionmentioning

confidence: 99%

White LEDs as broad spectrum light sources for spectrophotometry: Demonstration in the visible spectrum range in a diode‐array spectrophotometric detector

2010

View full text Add to dashboard Cite

show abstract

“…Optical fibres have been adapted for chemical sensing [10][11][12][13] and as wave-guides. Hauser et al [14,15] have used seven light-emitting diodes of different colours guided, one at a time, into a measuring cell by means of a fibre-optic coupler. Detection is carried out with photodiodes.…”

Section: Introductionmentioning

confidence: 99%

Novel fused-LEDs devices as optical sensors for colorimetric analysis

Lau

2004

Talanta

View full text Add to dashboard Cite

“…Figure 2. Emission spectrum (λ max 620nm) of the LED used in the integrated PEDD flow analysis device and the absorption spectrum (λ max 616nm) of 10mM BCG at pH 7 (ε = 1.2x10 4 Lmol -1 cm -1 ). The insert is the structure of the depronated BCG dye used.…”

Section: Discussionmentioning

confidence: 99%

“…Optical sensor configurations generally combine LED light source with photodiodes, which measure the light intensity after passage through the sample 2,[4][5][6][7][8] . The use of LEDs in photometric detectors has been reported as early as 1978 when Betteridge et al 9 used a gallium phosphide LED and a silicon phototransistor for the detection of metal ions.…”

Section: Introductionmentioning

confidence: 99%

Photometric detection in flow analysis systems using integrated PEDDs

Toole

Lau

Diamond

2005

Talanta

View full text Add to dashboard Cite

A novel inexpensive optical sensing technique has been developed for colorimetric flow analysis. This sensing system employs two LEDs whereby one is used as the light source and the other as a light detector. The LED used as light detector is reverse biased with a 5V supply so that the photocurrent generated by the incident light discharges the capacitance. Direct digital output is provided by a simple timer circuit that measures the time taken for this discharge process from 5V (logic 1) to 1.7V (logic 0). This sensing concept has been applied in flow analysis by constructing an optical flow cell with a pair of LEDs. Calibration of the integrated optical flow cell using a dye resulted in a linear response that obeys the Beer-Lambert Law. The flow rate, dynamic range, sensitivity and limits of detection were investigated. The system was also used for pH determination in the range of pH 2.5 -6.8 using bromocresol green (BCG). The pK a of BCG was successfully determined by this technique.

show abstract

A photometric detector based on a blue light-emitting diode

Cited by 25 publications

References 13 publications

White LEDs as broad spectrum light sources for spectrophotometry: Demonstration in the visible spectrum range in a diode‐array spectrophotometric detector

White LEDs as broad spectrum light sources for spectrophotometry: Demonstration in the visible spectrum range in a diode‐array spectrophotometric detector

Novel fused-LEDs devices as optical sensors for colorimetric analysis

Photometric detection in flow analysis systems using integrated PEDDs

Contact Info

Product

Resources

About