Former Humboldt Research Fellow and current Hanse-Wissenschaftskolleg Fellow at Constructor University Bremen and Institute for Chemistry and Biology of the Marine Environment (ICBM) at Carl von Ossietzky University Oldenburg.
Research interests
- Trace metals in marine ecosystems
- Development of analytical methods for environmental samples
- Development of simple and affordable optical and electrochemical sensing systems
- Environmental Chemistry in general
Research project:
My academic background is strongly oriented to Environmental Analytical Chemistry. In my current project at the Ocean Lab at Constructor University Bremen and at the ICBM at the Carl von Ossietzky Universität Oldenburg, I am working on the development of analytical methodologies for the quantification of manganese in the marine and related environments
Manganese (Mn) is the 11th element in abundance in the earth´s crust and an important element in marine sediments. It is a trace metal in the ocean and an essential trace nutrient and it is involved in the process of mineralization of organic matter. For all these reasons, manganese plays a key role in marine biogeochemical cycles, and assessing the concentration and speciation of this element is an essential issue to understand redox reaction-transport processes in sedimentary deposits.
Although instrumental techniques with excellent analytical performance are available for its quantification, these have the major drawback of requiring expensive instrumentation and consumables, as well as highly qualified personnel. Besides, these methods do not allow for measurements to be performed in the field.
Considering all these aspects, rapid, cost-effective, field-based methods for the quantification and speciationof Mn in pore waters will allow for direct monitoring on-site as well as for the assessment at substantially higher spatial and temporal resolution than would be possible using traditional methods. To achieve this goal, I developed sensing strips based on the immobilization of a colorimetric reagent for Mn. Upon contact with the sample, a chemical reaction between the specific reagent and the analyte takes place, which is evidenced by a colour change. The intensity of this change is quantified and related to the concentration of Mn in the sample with an in-house built colour sensor or by analysis of digital images of the sensors taken with a common smartphone.
Another approach is a photochemical reaction between manganese and tyrosine. Upon irradiation of the aminoacid, a fluorescent product is formed, whereby this reaction is enhanced by the presence of the analyte. Therefore, the fluorescence of the system can be correlated to the content in Mn in the sample.
To prove the applicability of the methods to real samples, I carry out rigorous study of the effect of potential interferents. Also, I test the sensors are tested on natural samples collected by Dr Koschinsky´s group (for example, on the M192 and SO301 cruises, where I had the opportunity to participate) and on porewater samples collected in the north beach of the Island of Spiekeroog in the frame of the DynaDeep project (DFG). The results are compared to the ones obtained using traditional spectroscopic techniques (ICP).
Publications
Pedre, I., Fröhberg, N., Waska, H., Koschinsky, A., & Pahnke, K. (2024). Simple and affordable colorimetric sensing strips for quantitative determination of total manganese in porewater samples. Limnology and Oceanography: Methods. https://doi.org/10.1002/lom3.10615
Pedre, I.*, González, G. A. (2022). Silver nanoparticles-based sensing platform for Fe3+ ions in complex matrices. Minerals Engineering 185 (2022) 107712. https://doi.org/10.1016/j.mineng.2022.107712
Pedre, I.*, Méndez De Leo, L., González, G. A. (2019). Cu2+-ion sensitive Surface on graphite electrodes. Analytical and Bioanalytical Chemistry 411(29):7761-7770. https://doi.org/10.1007/s00216-019-02142-0
Pedre, I., Battaglini, F., González, G. A. (2018). Disposable electrochemical sensor for rapid determination of ethyl xanthate in the mining industry Electroanalysis 30:2589-2596. https://doi.org/10.1002/elan.201800419
Pedre I., Cifuentes G., Sánchez-Loredo M. G., González G. A. (2016). Book chapter Técnica de detección electroquímica de tiourea presente en baños de electrorrefinería de cobre por medio de sensores conteniendo nanopartículas de plata (Electrochemical determination of thiourea in copper-refinery baths using sensors containing silver nanoparticles) inNuevos Procesos y Materiales para la Detección y Eliminación de Contaminantes en Agua (New processes and materials for the detection and elimination of hazardous substances in water). Moura Bernardes, A., Cifuentes Molina, G., Siqueira Rodrigues, M. A. and Rodríguez, M. A. (eds.)
Pedre, I., Méndez De Leo, L., Sánchez-Loredo, M. G., Battaglini, F., González, G. A. (2016). Electrochemical sensor for thiourea focused on metallurgical applications of copper. Sensors and Actuators B 232:383-389.https://doi.org/10.1016/j.snb.2016.03.154
Sciscenko I., Pedre I., Hunt A., Bogo H., González G. A. (2016). Determination of a typical additive in zinc electroplating baths. Microchemical Journal 127:226-230. https://doi.org/10.1016/j.microc.2016.03.015
Pedre, I., Battaglini, F., Labrada Delgado, G. J., Sánchez-Loredo, M. G., González, G. A. (2015). Detection of thiourea from electrorefining baths using silver nanoparticles-based sensors. Sensors and Actuators B 211:515-522.