An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources

Prairie, Michael W.; Frisbie, Seth H.; Rao, K. Uma; Saksri, Anyamanee H.; Parbat, Shreyas; Mitchell, Erika J.

doi:10.1371/journal.pone.0226761

Cited by 17 publications

(11 citation statements)

References 24 publications

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“…Submersible spectrophotometer sensors, widely used for drinking water quality monitoring (e.g. D' Acunha and Johnson 2019;González-Morales et al 2020;Prairie et al 2020), may, however, offer a reliable means to provide data on SS fingerprint properties at high frequency. Bass et al (2011) and Martínez-Carreras et al (2016) used submersible spectrophotometer sensors, measuring absorbance in the ultraviolet visible (UV-VIS) range, to estimate SS properties in situ.…”

Section: Introductionmentioning

confidence: 99%

High frequency un-mixing of soil samples using a submerged spectrophotometer in a laboratory setting—implications for sediment fingerprinting

et al. 2021

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Purpose This study tests the feasibility of using a submersible spectrophotometer as a novel method to trace and apportion suspended sediment sources in situ and at high temporal frequency. Methods Laboratory experiments were designed to identify how absorbance at different wavelengths can be used to un-mix artificial mixtures of soil samples (i.e. sediment sources). The experiment consists of a tank containing 40 L of water, to which the soil samples and soil mixtures of known proportions were added in suspension. Absorbance measurements made using the submersible spectrophotometer were used to elucidate: (i) the effects of concentrations on absorbance, (ii) the relationship between absorbance and particle size and (iii) the linear additivity of absorbance as a prerequisite for un-mixing. Results The observed relationships between soil sample concentrations and absorbance in the ultraviolet visible (UV–VIS) wavelength range (200–730 nm) indicated that differences in absorbance patterns are caused by soil-specific properties and particle size. Absorbance was found to be linearly additive and could be used to predict the known soil sample proportions in mixtures using the MixSIAR Bayesian tracer mixing model. Model results indicate that dominant contributions to mixtures containing two and three soil samples could be predicted well, whilst accuracy for four-soil sample mixtures was lower (with respective mean absolute errors of 15.4%, 12.9% and 17.0%). Conclusion The results demonstrate the potential for using in situ submersible spectrophotometer sensors to trace suspended sediment sources at high temporal frequency.

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Section: Introductionmentioning

confidence: 99%

High frequency un-mixing of soil samples using a submerged spectrophotometer in a laboratory setting—implications for sediment fingerprinting

et al. 2021

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“…Latorre et al (2019) recommended comparing the results using the PAN method against a more accurate method such as ICP‐MS to validate results. An LED‐spectrophotometer designed and built by Prairie et al (2020) used the PAN method at 560 nm, and found comparable results to the Hach DR‐2700, Hach 2010 and Thermal Electron Spectronic 20D+. Even though the PAN method promises low range Mn detection (0–0.700 mg/L, Method 8149), high levels of metals would still interfere with Mn (Hach, 2014).…”

Section: Emerging Methods For Field‐testingmentioning

confidence: 96%

Considerations for new manganese analytical techniques for drinking water quality management

et al. 2022

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Manganese (Mn) is a contaminant of emerging concern in drinking water, as recent epidemiologic evidence suggests an association between Mn exposure in drinking water and negative neurodevelopmental effects. The nature of Mn events in distribution systems can be sporadic and difficult to predict, with conventional laboratory methods being limited in their ability to provide the flexible on-line Mn monitoring. Emerging methods such as colorimetric and electrochemical methods offer advantages for monitoring as they have potential to be less expensive, rapid, and readily deployed in the field. These emerging methods, however, face hurdles to adaptation and acceptance including demonstration of sufficient accuracy, precision, sensitivity and yet-to-be resolved issues with interfering agents. These hurdles are not insurmountable, and investment is warranted in these novel methods to address pressing needs by the water industry to protect human health. This review paper highlights the opportunities and advantages of advancing field-testing techniques for Mn management.

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“…The light-emitting diode (LED) is a very good example because LED is environmentally friendly, easy to control its parameters, besides, LED has long-life use and provides a good quality of light [ 1 , 30 ]. More importantly, LED has a narrow full width at half maximum (FWHM) and produces less heat [ 31 ]. Thus, LED is an ideal illumination source for accurate investigation on the effects of light on Neurospora crassa .…”

Section: Introductionmentioning

confidence: 99%

Wavelengths and irradiances modulate the circadian rhythm of Neurospora crassa

et al. 2022

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The circadian rhythm affects the biological evolution and operating mechanisms of organisms. The impact of light on the circadian rhythm is a significant concern for both biology and human well-being. However, the relation between different wavelengths, irradiances, and circadian rhythm is unknown. In this study, we compared the effects of four different monochromatic light-emitting diode (LED) light and two different irradiances on the circadian rhythm of a wild-type Neurospora crassa. The results demonstrated that the circadian rhythm of Neurospora crassa can be modulated by violet (λp = 393 nm), blue (λp = 462 nm), and green (λp = 521 nm) light, regardless of the irradiances, in the visible region. Unexpectedly, for the yellow light (λp = 591 nm), the 2 W/m2 light had a more significant impact on circadian rhythm modulation than the 0.04 W/m2 light had. Considering the highest energy of yellow light (2.25 eV) is lower than the High Occupied Molecular Orbital (HOMO)-Lowest Unoccupied Molecular Orbital (LUMO) gap of WC-1 (2.43 eV). We speculate that there may be other potential photoreceptors that are involved in circadian rhythm modulation. The HOMO-LOMO gaps of these proteins are greater than 1.98 eV and less than 2.25 eV. These results provide a strong foundation for a deeper understanding of the impact of different light on the circadian rhythm and also shed light on the identification of new circadian rhythm modulation photoreceptors.

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An accurate, precise, and affordable light emitting diode spectrophotometer for drinking water and other testing with limited resources

Cited by 17 publications

References 24 publications

High frequency un-mixing of soil samples using a submerged spectrophotometer in a laboratory setting—implications for sediment fingerprinting

High frequency un-mixing of soil samples using a submerged spectrophotometer in a laboratory setting—implications for sediment fingerprinting

Considerations for new manganese analytical techniques for drinking water quality management

Wavelengths and irradiances modulate the circadian rhythm of Neurospora crassa

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