Evaluation of potsherds features using hyperspectral maps generated by μ-LIBS scanner

The micro-laser induced breakdown spectroscopy (µ-LIBS) technique allows performing fast elemental analyses, without sample preparation and thus making it specifically useful in the analysis of the composition of ancient potsherd. The µ-LIBS instrument is equipped with a microscope and a scanning system allowing to realize small craters (about Ø = 25 µm) in order to obtain detailed hyperspectral surfaces maps (up to a maximum size of one square centimeter). The data are processed by Self-Organizing Maps (SOMs) method to visualize in 2D representations allowing significant information on the technological features of ceramic samples.The micro-laser induced breakdown spectroscopy (µ-LIBS) technique allows performing fast elemental analyses, without sample preparation and thus making it specifically useful in the analysis of the composition of ancient potsherd. The µ-LIBS instrument is equipped with a microscope and a scanning system allowing to realize small craters (about Ø = 25 µm) in order to obtain detailed hyperspectral surfaces maps (up to a maximum size of one square centimeter). The data are processed by Self-Organizing Maps (SOMs) method to visualize in 2D representations allowing significant information on the technological features of ceramic samples

Sviluppo di un metodo SERS (Surface Enhanced Raman Spectroscopy) per lo studio di coloranti naturali utilizzati in campioni tessili.

Il lavoro di tesi si è incentrato sullo sviluppo di una metodica SERS, andando a provare diversi substrati, applicabile nell'analisi di coloranti organici naturali estratti da filati. Successivamente sono state effettuate prove di analisi anche sulla fibra tal quale. In fine si è proceduto con la caratterizzazione di campioni incogniti

Low-melting point agarose as embedding medium for MALDI mass spectrometry imaging and laser-capture microdissection-based proteomics

Abstract The combination of MALDI mass spectrometry imaging, laser-capture microdissection, and quantitative proteomics allows the identification and characterization of molecularly distinct tissue compartments. Such workflows are typically performed using consecutive tissue sections, and so reliable sectioning and mounting of high-quality tissue sections is a prerequisite of such investigations. Embedding media facilitate the sectioning process but can introduce contaminants which may adversely affect either the mass spectrometry imaging or proteomics analyses. Seven low-temperature embedding media were tested in terms of embedding temperature and cutting performance. The two media that provided the best results (5% gelatin and 2% low-melting point agarose) were compared with non-embedded tissue by both MALDI mass spectrometry imaging of lipids and laser-capture microdissection followed by bottom-up proteomics. Two out of the seven tested media (5% gelatin and 2% low-melting point agarose) provided the best performances on terms of mechanical properties. These media allowed for low-temperature embedding and for the collection of high-quality consecutive sections. Comparisons with non-embedded tissues revealed that both embedding media had no discernable effect on proteomics analysis; 5% gelatin showed a light ion suppression effect in the MALDI mass spectrometry imaging experiments, 2% agarose performed similarly to the non-embedded tissue. 2% low-melting point agarose is proposed for tissue embedding in experiments involving MALDI mass spectrometry imaging of lipids and laser-capture microdissection, proteomics of consecutive tissue sections

Applications of laser-induced breakdown spectroscopy in cultural heritage and archaeology: A critical review

In this paper, we present a critical review on the applications of the Laser-Induced Breakdown Spectroscopy (LIBS) technique in cultural heritage and archaeology. The strategies used by the groups involved in this kind of research for the analysis of the typical materials of interest (metals, pigments, pottery, glass, etc.) are discussed in detail, as well as the use of LIBS in combination with other techniques (LIBS and Raman, LIBS and XRF, and LIBS and MS). Specific applications of LIBS as a support for cultural heritage restoration and the application of the technique for the analysis of underwater objects are presented in separate sessions. In conclusion, new trends of LIBS for cultural heritage and archaeology (micro-LIBS analysis, 3D elemental imaging, and surface- and nanoparticle-enhanced LIBS) are introduced and discussed

Laser-Induced Breakdown Spectroscopy elemental mapping of the construction material from the Smederevo Fortress (Republic of Serbia)

Archeological mortars are often composed of highly inhomogeneous materials and detailed analysis in most cases can be quite difficult. In this work, a Laser-Induced Breakdown Spectroscopy (LIBS) equipment with microscopic-scale spatial resolution was used to image the distribution of elements on real archeological samples of mortars and construction material used in the foundations of the Smederevo Fortress (Republic of Serbia). A double-pulse Nd:YAG at the fundamental wavelength (λ = 1064 nm) and a CCD spectrometer coupled with a commercial microscope were used to generate the plasma and acquire the LIBS spectra. Thanks to the combined use of an unsupervised clustering algorithm and the calibration-free procedure, the results obtained show that it is possible to obtain a good discrimination between materials of different composition, allowing a quick classification for further mineral-petrographic investigations

Laser-Induced Breakdown Spectroscopy for Determination of Spectral Fundamental Parameters

In this review, we report and critically discuss the application of LIBS for the determination of plasma-emission fundamental parameters, such as transition probabilities, oscillator strengths, Stark broadening and shifts, of the emission lines in the spectrum. The knowledge of these parameters is of paramount importance for plasma diagnostics or for quantitative analysis using calibration-free LIBS methods. In the first part, the theoretical basis of the analysis is laid down; in the second part, the main experimental and analytical approaches for the determination by LIBS of the spectral line spectroscopic parameters are presented. In the conclusion, the future perspectives of this kind of analysis are discussed

Flaxseed Cake as a Tool for the Improvement of Nutraceutical and Sensorial Features of Sourdough Bread

Flaxseed has been recently studied for the formulation of healthy functional foods that are also useful for the prevention of chronic diseases. In this context, the production of sourdough bread fortified with different percentages of flaxseed cake was performed and the interactions among the bioactive compounds derived from both sourdough and flaxseed cake were investigated. The organoleptic properties as well as nutraceutical and chemical characteristics regarding pH, ethanol, lactic and acetic acid content, fatty acids profile, the concentration of total polyphenols, antioxidant capacity, and aroma volatile organic compounds were determined to evaluate the efficacy of leavening in the different matrices in comparison with the traditional bread. The results obtained demonstrated that flaxseed cake-enriched sourdough bread can represent a potential vehicle for bioactive compounds with the possibility of obtaining high-quality products with improved nutritional profiles and desired health attributes. Furthermore, the bread obtained with the addition of 7.5% of flaxseed cake was individuated as the best formulation to produce sourdough bread fortified with flaxseed cake by the overlap between three series of information coming from physical-chemical, nutritional, and sensorial analyses. In conclusion, in the operating conditions adopted, the use of flaxseed cake could represent a viable alternative for the production of fortified bread based on sourdough technology

Analytical and mathematical methods for revealing hidden details in ancient manuscripts and paintings: A review

In this work, a critical review of the current nondestructive probing and image analysis approaches is presented, to revealing otherwise invisible or hardly discernible details in manuscripts and paintings relevant to cultural heritage and archaeology. Multispectral imaging, X-ray fluorescence, Laser-Induced Breakdown Spectroscopy, Raman spectroscopy and Thermography are considered, as techniques for acquiring images and spectral image sets; statistical methods for the analysis of these images are then discussed, including blind separation and false colour techniques. Several case studies are presented, with particular attention dedicated to the approaches that appear most promising for future applications. Some of the techniques described herein are likely to replace, in the near future, classical digital photography in the study of ancient manuscripts and paintings. Keywords: Image analysis, Cultural heritage, Archaeology, Multispectral imaging, Ancient manuscripts, Blind separation technique

Increasing resolution in chemical mapping of geomaterials: From X-ray fluorescence to laser-induced breakdown spectroscopy

Laser-Induced Breakdown Spectroscopy (LIBS) micro-mapping is an important analytical tool for the study of geomaterials. In this work, this technique was applied, for the first time, to the analysis of alkali-activated materials and geopolymers, as well as rocks, mortars and bricks. The results obtained were compared with the ones obtained using Energy-Dispersive X-Ray Fluorescence (ED-XRF) macro-mapping and the advantages of the LIBS approach (speed, lateral and in-depth resolution, capability of light elements analysis) were highlighted. The issues associated with the quantitative determination of the samples' composition from the analysis of the LIBS spectra were also briefly discussed