63 research outputs found
Technical report on chemical sensors performance
The report will present an overview of sensors that are useful for the study of seeps, and present a detailed comparison of commercial and prototype CO2 and pH sensors.
CO2 sensors: 1) Severinghaus CO2 sensors (Microelectrodes ltd), 2) the HydroC-ÂâCO2 logger sensor (CONTROS GmbH), 3) the âGasPro-ÂâpCO2â (developed by the team coordinated by Prof. S. Lombardi; Sapienza -Ââ University of Rome-ÂâCERI), 4) the MuFo (Multifiber Optode logger, developed in this project in a collaboration between Prof. I. Klimant University Graz and the MPI-ÂâMM).
pH sensors: 1) glass electrodes Microelectrodes ltd), 2) optodes (developed in this project in a collaboration between Prof. I. Klimant University Graz and the MPI-ÂâMM), 3) SeaFET (ion-Ââselective field-Ââeffect transistor, Satlantic)
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 (Ίprot 0.86; Ίdeprot 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 670â700 nm for the neutral form, λmax 725â760 nm for the mono-anionic form, λmax 785â830 nm for the di-anionic form), high molar absorption coefficients of up to 77 000 Mâ1 cmâ1 and unmatched photostability. Depending on the electron-withdrawing or electron-donating effect of the substituents the pKa values are tunable (8.7â10.7). Therefore, optical carbon dioxide sensors based on the presented dyes cover diverse dynamic ranges (0.007â2 kPa; 0.18â20 kPa and 0.2â100 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
Investigation of benthic communities at submarine CO2 vents off Panarea Island (Italy): cruise report ECO2-3 (2012)
Highly Sensitive Poisoning-Resistant Optical Carbon Dioxide Sensors for Environmental Monitoring
A new optical carbon dioxide sensor for environmental monitoring is presented. It combines a robust and long-term stable sensing material with a compact read-out device. The sensing material relies on a NIR pH indicator immobilized into ethyl cellulose along with a quaternary ammonium base. The perfluorinated polymer Hyflon AD 60 used as a protection layer significantly enhances the long-term and mechanical stability of the sensor foils, as well as the robustness against poisoning gases, e.g. hydrogen sulfide. The sensor can be stored under ambient conditions for more than six weeks, whereas sensors covered with silicone rubber deteriorate within one week under the same conditions. The complete sensor device is applicable after a three-point (re)calibration without a preconditioning step. The carbon dioxide production and consumption of the water plant Egeria densa was measured in the laboratory. Furthermore, results of profiling carbon dioxide measurements during a research cruise on the Baltic Sea at water depths up to 225 m are presented
Cruise Report ECO2-8 (Panarea Island, Italy): EFFECT OF SEABED CO2 EMISSIONS ON SHALLOW BENTHIC MICROBIOTA (PANAREA ISLAND)
Continuous pCO2 measurements with a multiple fibre optics device at station MUFO-4 during cruise ECO2-8
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