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- Giménez-Gómez, Pablo, 1984-, et al.
(författare)
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Distance-based paper analytical device for the determination of dissolved inorganic carbon concentration in freshwater
- 2023
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier BV. - 0925-4005 .- 1873-3077. ; 385
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Tidskriftsartikel (refereegranskat)abstract
- Dissolved inorganic carbon (DIC) levels in freshwaters play a key role in the equilibrium of the carbon cycle between the atmosphere, water and living beings. Standard classical methods for DIC determination generally involve bulky and expensive equipment used in centralized laboratories, resulting in time-consuming processes that do not allow for adequate monitoring in the field. In order to address this challenge, we have developed a distance-based paper analytical device (PAD) for on-site determination of DIC in water. The portable, cost-effective and easy-to-use device was based on the miniaturization and integration of a classical acid-base colorimetric titration on a paper channel, enabling an accurate determination of DIC in less than 20 min. The length of the blue colored line in the detection channel after being filled with the sample was related to the DIC concentration in the sample. The reagent solution used to modify the titration channel was optimized so that DIC concentrations in the range 50–1000 mg L−1 could be measured. The long-term stability of the paper-based device was also evaluated, demonstrating a working stability for more than 70 days after their fabrication, an important characteristic for in-the-field analysis. Finally, the PAD was validated with different water samples, i.e. tap water, commercial bottled drinking water and water samples from a mine, with excellent agreement between the results obtained from the PAD and the standard method. This demonstrates the high potential of the proposed paper analytical device to quantify DIC in situ by minimally-trained personnel without the need for peripheral equipment, which represents an important advance compared to the current limited analysis systems.
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| 2. |
- Santigosa-Murillo, Elia, et al.
(författare)
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A novel integrated platform enabling simultaneous microextraction and chemical analysis on-chip
- 2023
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Ingår i: Microchemical journal (Print). - 0026-265X .- 1095-9149. ; 193
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Tidskriftsartikel (refereegranskat)abstract
- The nature and size of biological, pharmaceutical or environmental analytes complicates their extraction and detection outside of laboratories and near the site of interest by the current chromatographic methods because they require the combination of bulky extraction and detection methods. In order to solve this inefficient centralized control, a ground-breaking and miniaturized proof of concept platform is developed in this work. The platform integrates for the very first time an electro-membrane extraction process and an accurate analyte quantification method in the same device, by using electrochemical impedance spectroscopy (EIS) as analytical technique. The microfluidic flow cell, including the microfluidic components, is fabricated in polymeric materials by rapid prototyping techniques. It comprises a four-electrode platinum thin-film chip that enables the control of the microextraction and the full characterization of the process, i.e., extraction efficiency determination, at the same time. The microfluidic system has been simulated by using computational tools, enabling an accurate prediction of the effect of the different experimental conditions in the microextraction efficiency. The platform has been validated in the microextraction of the nonsteroidal anti-inflammatory drug ketoprofen in a range from 0.5 ppm to 6 ppm. The predicted microextraction efficiency values obtained by EIS were compared with those calculated from the high-performance liquid chromatography coupled with a diode array detector (HPLC-DAD), showing an excellent agreement. This validates the high potential of this integrated and miniaturized platform for the simultaneous extraction by electro-membrane and also the analysis within the platform, solving one of the of most important limitations of current systems.
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