7 research outputs found
New highly fluorescent pH indicator for ratiometric RGB imaging of pCO2
A new diketo-pyrrolo-pyrrole (DPP) indicator dye for optical sensing of carbon dioxide is prepared via a simple one step synthesis from commercially available low cost 'Pigment Orange 73'. The pigment is modified via alkylation of one of the lactam nitrogens with a tert-butylbenzyl group. The indicator dye is highly soluble in organic solvents and in polymers and shows pH-dependent absorption (λmax 501 and 572 nm for the protonated and deprotonated forms, respectively) and emission spectra (λmax 524 and 605 nm for the protonated and deprotonated forms, respectively). Both the protonated and the deprotonated forms show high fluorescence quantum yields (Φprot 0.86; Φdeprot 0.66). Hence, colorimetric read-out and ratiometric fluorescence intensity measurements are possible. The emission of the two forms of the indicator excellently matches the response of the green and the red channels of an RGB camera. This enables imaging of carbon dioxide distribution with a simple and low cost optical set-up. The sensor based on the new DPP dye shows very high sensitivity and is particularly promising for monitoring atmospheric levels of carbon dioxide
NIR optical carbon dioxide sensors based on highly photostable dihydroxy-aza-BODIPY dyes
A new class of pH-sensitive indicator dyes for optical carbon dioxide sensors based on di-OH-aza-BODIPYs is presented. These colorimetric indicators show absorption maxima in the near infrared range (λmax 670–700 nm for the neutral form, λmax 725–760 nm for the mono-anionic form, λmax 785–830 nm for the di-anionic form), high molar absorption coefficients of up to 77 000 M−1 cm−1 and unmatched photostability. Depending on the electron-withdrawing or electron-donating effect of the substituents the pKa values are tunable (8.7–10.7). Therefore, optical carbon dioxide sensors based on the presented dyes cover diverse dynamic ranges (0.007–2 kPa; 0.18–20 kPa and 0.2–100 kPa), which enables different applications varying from marine science and environmental monitoring to food packaging. The sensors are outstandingly photostable in the absence and presence of carbon dioxide and can be read out via absorption or via the luminescence-based ratiometric scheme using the absorption-modulated inner-filter effect. Monitoring of the carbon dioxide production/consumption of a Hebe plant is demonstrated
Diketo-Pyrrolo-Pyrrole Dyes as New Colorimetric and Fluorescent pH Indicators for Optical Carbon Dioxide Sensors
New indicators for optical CO2 sensors are synthesized in two steps from the commercially available diketo-pyrrolo-pyrrole (DPP) pigments Irgazin Ruby and Irgazin Scarlet. After introduction of bis(2-ethylhexyl) sulfonamide groups via a simple two-step synthesis, the pigments are rendered highly soluble in organic solvents and in polymers and show pH-dependent absorption and emission spectra. The new indicators have molar absorption coefficients in a 20 000–50 000 M–1 cm–1 range, possess quantum yields close to unity, and feature good photostability. The indicators along with a quaternary ammonium base are embedded into ethyl cellulose to give optical carbon dioxide sensors. The absorption and emission spectra of the deprotonated form are bathochromically shifted by more than 100 nm compared to the neutral form (λmax absorption 496–550 nm; λmax emission 564–587 nm). This enables colorimetric read-out and self-referenced ratiometric fluorescence intensity measurements. Importantly, the dynamic range of the sensors based on the new indicators is significantly different (0–10 kPa and 1–100 kPa CO2) that enables a broad variety of applications.
New DPP dyes are conveniently prepared from commercially available pigments and represent a new class of colorimetric and fluorescent pH indicators for optical carbon dioxide sensors
Diketo-Pyrrolo-Pyrrole Dyes as New Colorimetric and Fluorescent pH Indicators for Optical Carbon Dioxide Sensors
New
indicators for optical CO<sub>2</sub> sensors are synthesized
in two steps from the commercially available diketo-pyrrolo-pyrrole
(DPP) pigments Irgazin Ruby and Irgazin Scarlet. After introduction
of bisÂ(2-ethylhexyl) sulfonamide groups via a simple two-step synthesis,
the pigments are rendered highly soluble in organic solvents and in
polymers and show pH-dependent absorption and emission spectra. The
new indicators have molar absorption coefficients in a 20 000–50 000
M<sup>–1</sup> cm<sup>–1</sup> range, possess quantum
yields close to unity, and feature good photostability. The indicators
along with a quaternary ammonium base are embedded into ethyl cellulose
to give optical carbon dioxide sensors. The absorption and emission
spectra of the deprotonated form are bathochromically shifted by more
than 100 nm compared to the neutral form (λ<sub>max</sub> absorption
496–550 nm; λ<sub>max</sub> emission 564–587 nm).
This enables colorimetric read-out and self-referenced ratiometric
fluorescence intensity measurements. Importantly, the dynamic range
of the sensors based on the new indicators is significantly different
(0–10 kPa and 1–100 kPa CO<sub>2</sub>) that enables
a broad variety of applications.New DPP dyes are conveniently
prepared from commercially available
pigments and represent a new class of colorimetric and fluorescent
pH indicators for optical carbon dioxide sensors