A simple method to reduce optical cross‐talk effects in chemical imaging with planar optodes

Mayr, Torsten; Ungerböck, Birgit; Mistlberger, Günter; Borisov, Sergey M.; Klimant, Ingo

doi:10.4319/lom.2012.10.101

Cited by 4 publications

(6 citation statements)

References 17 publications

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“…Intensity-based fluorescence imaging methods have been widely used in previous optical chemical sensing systems 26 27 . However, it suffers from various interferences such as non-homogeneity of the light source or sensor layer, background reflection, photobleaching, or leakage of indicator dye for those methods based on one measurement of a single steady fluorescence intensity 7 28 . To alleviate these interferences, a well documented ratiometric approach based on two imaging intensities was performed in this system.…”

Section: Resultsmentioning

confidence: 99%

High-resolution Imaging of pH in Alkaline Sediments and Water Based on a New Rapid Response Fluorescent Planar Optode

Han

Yao

et al. 2016

Sci Rep

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A new dual-lumophore optical sensor combined with a robust RGB referencing method was developed for two-dimensional (2D) pH imaging in alkaline sediments and water. The pH sensor film consisted of a proton-permeable polymer (PVC) in which two dyes with different pH sensitivities and emission colors: (1) chloro phenyl imino propenyl aniline (CPIPA) and (2) the coumarin dye Macrolex® fluorescence yellow 10 GN (MFY-10 GN) were entrapped. Calibration experiments revealed the typical sigmoid function and temperature dependencies. This sensor featured high sensitivity and fast response over the alkaline working ranges from pH 7.5 to pH 10.5. Cross-sensitivity towards ionic strength (IS) was found to be negligible for freshwater when IS <0.1 M. The sensor had a spatial resolution of approximately 22 μm and aresponse time of <120 s when going from pH 7.0 to 9.0. The feasibility of the sensor was demonstrated using the pH microelectrode. An example of pH image obtained in the natrual freshwater sediment and water associated with the photosynthesis of Vallisneria spiral species was also presented, suggesting that the sensor held great promise for the field applications.

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Section: Resultsmentioning

confidence: 99%

High-resolution Imaging of pH in Alkaline Sediments and Water Based on a New Rapid Response Fluorescent Planar Optode

Han

Yao

et al. 2016

Sci Rep

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“…HPTS based sensors can be interrogated with dual excitation/single emission [18,75], single excitation/dual emission and dual excitation/dual emission (Section 3.3.4), [120]. For the single excitation/dual emission approach an additional dye can be added to increase the sensor brightness and to serve as the ratiometric reference [82,121]. Furthermore, HPTS shows excellent photostability [122].…”

Section: Ph Indicatorsmentioning

confidence: 98%

“…The images were recorded with a five second interval. Images are recorded with a colour ratio metric imaging approach [82] using a 1%/2% PtTFPP/Macrolex yellow dye mix [121]. Unpublished results of Morten Larsen and Ronnie N. Glud. biogeochemical processes, especially of the importance of microbial niches in aquatic sediments.…”

Section: Dgt and Detmentioning

confidence: 99%

Two decades of chemical imaging of solutes in sediments and soils – a review

Santner

Larsen

Kreuzeder

et al. 2015

Analytica Chimica Acta

168

130

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The increasing appreciation of the small-scale (sub-mm) heterogeneity of biogeochemical processes in sediments, wetlands and soils has led to the development of several methods for high-resolution two-dimensional imaging of solute distribution in porewaters. Over the past decades, localised sampling of solutes (diffusive equilibration in thin films, diffusive gradients in thin films) followed by planar luminescent sensors (planar optodes) have been used as analytical tools for studies on solute distribution and dynamics. These approaches have provided new conceptual and quantitative understanding of biogeochemical processes regulating the distribution of key elements and solutes including O2, CO2, pH, redox conditions as well as nutrient and contaminant ion species in structurally complex soils and sediments. Recently these methods have been applied in parallel or integrated as so-called sandwich sensors for multianalyte measurements. Here we review the capabilities and limitations of the chemical imaging methods that are currently at hand, using a number of case studies, and provide an outlook on potential future developments for two-dimensional solute imaging in soils and sediments.

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“… 9 To cope with noise arising from the optode, different approaches for optode fabrication have been proposed. 29 Fischer et al 26 presented a high-resolution optode based on a fiber optic faceplate consisting of millions of individual light-guiding fibers, which prevents optical crosstalk within the optode. In another approach, Kühl et al 30 reduced the thickness of the O 2 optode to 1–2 μm (cf.…”

Section: Introductionmentioning

confidence: 99%

“…In general, sources of noise are manifold, including optical crosstalk within the optode (e.g., light guidance effects , and optode inhomogeneity). Further sources of noise are noise arising during image acquisition summarized as transduction noise or due to nonoptimal camera settings, for instance when the ISO value must be high or the exposure time long .…”

Section: Introductionmentioning

confidence: 99%

Noise versus Resolution in Optical Chemical Imaging─How Reliable Are Our Measurements?

2022

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Optical chemical imaging has established itself as a valuable technique for visualizing analyte distributions in 2D, notably in medical, biological, and environmental applications. In particular for image acquisitions on small scales between few millimeter to the micrometer range, as well as in heterogeneous samples with steep analyte gradients, image resolution is essential. When individual pixels are inspected, however, image noise becomes a metric as relevant as image accuracy and precision, and denoising filters are applied to preserve relevant information. While denoising filters smooth the image noise, they can also lead to a loss of spatial resolution and thus to a loss of relevant information about analyte distributions. To investigate the trade-off between image resolution and noise reduction for information preservation, we studied the impact of random camera noise and noise due to incorrect camera settings on oxygen optodes using the ratiometric imaging technique. First, we estimated the noise amplification across the calibration process using a Monte Carlo simulation for nonlinear fit models. We demonstrated how initially marginal random camera noise results in a significant standard deviation (SD) for oxygen concentration of up to 2.73% air under anoxic conditions, although the measurement was conducted under ideal conditions and over 270 thousand sample pixels were considered during calibration. Second, we studied the effect of the Gaussian denoising filter on a steep oxygen gradient and investigated the impact when the smoothing filter is applied during data processing. Finally, we demonstrated the effectiveness of a Savitzky-Golay filter compared to the well-established Gaussian filter.

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A simple method to reduce optical cross‐talk effects in chemical imaging with planar optodes

Cited by 4 publications

References 17 publications

High-resolution Imaging of pH in Alkaline Sediments and Water Based on a New Rapid Response Fluorescent Planar Optode

High-resolution Imaging of pH in Alkaline Sediments and Water Based on a New Rapid Response Fluorescent Planar Optode

Two decades of chemical imaging of solutes in sediments and soils – a review

Noise versus Resolution in Optical Chemical Imaging─How Reliable Are Our Measurements?

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