A Low-Cost Quantitative Absorption Spectrophotometer

Albert, Daniel R.; Todt, Michael A.; Davis, H. S.

doi:10.1021/ed200829d

Cited by 106 publications

(101 citation statements)

References 13 publications

(20 reference statements)

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“…[20][21][22][23][24][25][26][27][28][29] For example, we and others have constructed low-cost photometers based on this principle to measure i) antibodies against HIV in serum, 21 ii) hemoglobin [22][23] in blood, and iii) fluoride 27 and mercury 29 in water samples.…”

Section: Introductionmentioning

confidence: 99%

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

et al. 2015

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This paper demonstrates that, for applications in resource-limited environments, expensive microplate spectrophotometers-which are used in many central laboratories for parallel measurement of absorbance of samples-can be replaced by photometers based on inexpensive and ubiquitous, consumer electronic devices (e.g., scanners and cell-phone cameras). Two devices-i) a flatbed scanner operating in transmittance mode and ii) a camera-based photometer constructed from a cell phone camera, a planar light source, and a cardboard box-demonstrate the concept. These devices illuminate samples in microtiter plates from one side, and use the RGB-based imaging sensors of the scanner/camera to measure the light transmitted to the other side. The broadband absorbance of samples (RGB-resolved absorbance) can be calculated using the RGB color values of only three pixels per micro-well. Rigorous theoretical analysis establishes a well-defined relationship between the absorbance spectrum of a sample and its corresponding RGB-resolved absorbance. The linearity and precision of measurements performed with these low-cost photometers on different dyes that absorb across the range of the visible spectrum, and chromogenic products of assays (e.g., enzymatic, ELISA) demonstrates that these low-cost photometers can be used reliably in a broad range of chemical and biochemical analyses. The ability to perform accurate measurements of absorbance on liquid samples, in parallel and at low cost, would enable testing, typically reserved for well-equipped clinics and laboratories, to be performed in circumstances where resources and expertise are limited.

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Section: Introductionmentioning

confidence: 99%

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

et al. 2015

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“…Electronic transduction of results can be accomplished via electrochemical detection [38], an approach that can leverage the extensive development of low-cost electrochemical blood glucose meters [41]. Colorimetric detection generally requires the use of cloud-based imageprocessing capabilities in order to achieve electrical transduction of bacterial contamination at the WHO guideline of 0 cfu/100 mL [6,10], but advances in low-cost light-emitting diode (LED)-based spectrophotometers [72][73][74] and spectrophotometers utilizing smartphone optics [75,76] may lead to low-cost colorimetric sensors offering electrical transduction at the required sensitivity without the need for image processing.…”

Section: Identification Of Appropriate Sensing Technologies From Usermentioning

confidence: 99%

Fieldwork-based determination of design priorities for point-of-use drinking water quality sensors for use in resource-limited environments

et al. 2020

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Improved capabilities in microfluidics, electrochemistry, and portable assays have resulted in the development of a wide range of point-of-use sensors intended for environmental, medical, and agricultural applications in resource-limited environments of developing countries. However, these devices are frequently developed without direct interaction with their often-remote intended user base, creating the potential for a disconnect between users' actual needs and those perceived by sensor developers. As different analytical techniques have inherent strengths and limitations, effective measurement solution development requires determination of desired sensor attributes early in the development process. In this work, we present our findings on design priorities for point-of-use microbial water sensors based on fieldwork in rural India, as well as a guide to fieldwork methodologies for determining desired sensor attributes. We utilized group design workshops for initial identification of design priorities, and then conducted choice-based conjoint analysis interviews for quantification of user preferences among these priorities. We found the highest user preference for integrated reporting of contaminant concentration and recommended actions, as well as significant preferences for mostly reusable sensor architectures, same-day results, and combined ingredients. These findings serve as a framework for future microbial sensor development and a guide for fieldwork-based understanding of user needs. OPEN ACCESSCitation: Bono MS, Jr., Beasley S, Hanhauser E, Hart AJ, Karnik R, Vaishnav C (2020) Fieldworkbased determination of design priorities for pointof-use drinking water quality sensors for use in resource-limited environments. PLoS ONE 15(1): e0228140. https://doi.org/10.

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“…However, this system lacks a reference channel. Other approaches use moveable optics to scan through the spectral range [29]. However, the use of mechanical parts increases the complexity of the system.…”

Section: Introductionmentioning

confidence: 99%

2-LED-µSpectrophotometer for Rapid On-Site Detection of Pathogens Using Noble-Metal Nanoparticle-Based Colorimetric Assays

et al. 2020

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Novel point-of-care compatible methods such as colorimetric assays have become increasingly important in the field of early pathogen detection. A simple and hand-held prototype device for carrying out DNA-amplification assay based on plasmonic nanoparticles in the colorimetric detection is presented. The low-cost device with two channels (sample and reference) consists of two spectrally different light emitting diodes (LEDs) for detection of the plasmon shift. The color change of the gold-nanoparticle-DNA conjugates caused by a salt-induced aggregation test is examined in particular. A specific and sensitive detection of the waterborne human pathogen Legionella pneumophila is demonstrated. This colorimetric assay, with a simple assay design and simple readout device requirements, can be monitored in real-time on-site.

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A Low-Cost Quantitative Absorption Spectrophotometer

Cited by 106 publications

References 13 publications

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

Broadly Available Imaging Devices Enable High-Quality Low-Cost Photometry

Fieldwork-based determination of design priorities for point-of-use drinking water quality sensors for use in resource-limited environments

2-LED-µSpectrophotometer for Rapid On-Site Detection of Pathogens Using Noble-Metal Nanoparticle-Based Colorimetric Assays

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