As the conventional techniques used for the analysis of biological attack require sampling, and are usually costly and time-consuming, a completely non-destructive method that can be used in situ, as is LED-IF (LED-Induced Fluorescence), could be proven vital for the protection of a monument. The potential of the system is examined on several artefacts composed of different substrates presenting diverse types of biodeterioration and a first classification is achieved. Various aspects are also discussed, such as the selection of the proper LED wavelength for this type of compounds, while a methodology proposed for its use in the lab and/or in situ will be presented. The LED-IF system is developed within the project CALLOS: Conservation of Athens antiquities with Laser and Lidar technologies Open to Science and public (MIS-5056208), an \"open innovation in culture\" action co-funded by the European Regional Development Fund (ERDF) and national resources through the Operational Program \"Competitiveness, Entrepreneurship & Innovation\" (NSRF-EPAnEK). ## References  
* _Macedo et al. 2009_ Macedo, M.F. ; Miller, A.Z. ; Dionisio, A.; Saiz-Jimenez, C. Biodiversity of Cyanobacteria and Green Algae on Monuments in the Mediterranean Basin: An Overview. _Microbiology_**2009**, _155_, 3476-3490. * _Paper-Based Device for the Determination Chloride as a Biomarker of Cystic Fibrosis Based on the Photochemical Reduction in Silver Halide Nanocrystals_
* _Matiaki_\({}^{*}\)_, A. G. Vlessidis and D. L. Giokas
* _Department of Chemistry, University of Ioannina, 45110 Ioannina, Greece
* _Correspondence: chmatiaki@gmail.com_  
A simple method for the determination of chloride anions in sweat as a biomarker of cystic fibrosis is described. The method relies on the different colorimetric response of silver ions and silver chloride crystals when exposed to UV light. Silver ions change from colourless to dark grey-brown due to the formation of nanosized Ag, while AgCl exhibits a less intense colour change from white to slightly grey. The analytical signal is obtained as mean grey area intensity on the paper surface with a simple camera, and is used to directly quantify the concentration of chloride anions in the sample (Figure 44). The method requires only three steps to perform (addition of sample, irradiation, and measurement) and is performed with minimum sample volume (2 \(\upmu\)L). The working range of the method covers the entire diagnostic range of chloride levels related to cystic fibrosis (10-140 mM) offers low detection limits (2.7 mM Cl\({}^{-}\)) and satisfactory recoveries (95.2-108.7%) and reproducibility. 18.16. CeO\({}_{2}\):Fe\({}_{2}\)O\({}_{3}\) Nanoparticles Modified Electrode for the Sensitive and Selective Quantification of Lipoic Acid G. Ziyatdinova * and L. Gimadutdinova Analytical Chemistry Department, Kazan Federal University, Kremleyevskaya, 18, 420008 Kazan, Russian * Correspondence: Ziyatdinovag@mail.ru  
Metal oxide nanoparticles are widely applied as electrode surface modifiers in modern organic electroanalysis. Among them, inert metal oxides nanoparticles (TiO\({}_{2}\), In\({}_{2}\)O\({}_{3}\), CeO\({}_{2}\), ZnO, Fe\({}_{3}\)O\({}_{4}\), etc.) are of interest as far as providing a highly effective area of electrodes, electrocatalytic activity, high selectivity, and sensitivity of target analyte determination, as shown in the example of phenolic compounds [1,2], neuromediators [3,4], and some pharmaceuticals [5,6]. The combination of several metal oxide nanoparticles can provide improvement of analytical characteristics. Among the analytes, a group of S-containing compounds is rarely investigated. In particular, lipoic acid is almost out of consideration. A novel modified electrode based on CeO\({}_{2}\):Fe\({}_{2}\)O\({}_{3}\) nanoparticles has been developed for the lipoic acid quantification. Electrode surface modification provides 5.6-fold increase in the lipoic acid oxidation currents and 20 mV anodic shift of the oxidation potential.