## 4 Conclusions  
In this study, a chemometrics-assisted calibration of a Z-903 h-LIBS device was developed. Spectral data collected on seventeen silica-based standard samples were preprocessed using a Whittaker filter, which performed better than the airPLS algorithm, for baseline correction and normalized via SNV. The Kennard-Stone algorithm was employed to split the dataset into calibration and validation subsets to allow for an internal validation step. Multivariate regression analysis was then carried out by PLS regression, supported by a VIP variable selection routine. The proposed PLS-VIP method proved to be highly promising, achieving limits of quantification (LOQ) comparable with those reported for bench-top LIBS systems. Moreover, the performances in prediction across nineteen elements, encompassing major and minor components, were critically compared to the literature and resulted in satisfactory findings, enabling rapid quantitative determination in situ. However, measurements performed from real artifacts require further optimization to address issues related to surface roughness or microstructural variations, which can affect spectral quality and accuracy. The calibrated h-LIBS device was then used to analyze nine silica-based samples from the Archaeological Park of Tindari (Italy). The composition of obsidian and millstone fragments suggested a strong similarity to volcanic materials from the nearby Aeolian Islands. For the glass samples, elemental composition revealed consistency with Roman-era glass artifacts found in another Sicilian archaeological area (i.e., Roman _Domus_ of Villa San Pancrazio in Taormina), suggesting a glass-making technology using nation as a flux, lime as stabilizer, and calcareous sands as the primary raw material. The two brick samples exhibited slightly different elemental profiles, potentially indicating varied production techniques. However, definitive classification of these ceramic samples requires additional comparative materials and further analyses, such as powder XRD, to identify specific high-temperature crystalline phases. While the results highlight the potential of using h-LIBS devices for archaeological materials analysis, the study is limited by the relatively narrow sample diversity, as the calibration was developed using silica-based standards. This restricts the generalizability of the model to other material matrices, such as carbonates or metals. Furthermore, environmental factors such as humidity and temperature fluctuations during measurements were not systematically evaluated, which may influence calibration stability. Another limitation is the absence of a comparative evaluation with other established techniques like pXRF, which is commonly used in the field. Future research will focus on expanding the reference dataset to include a broader range of materials and elemental compositions, including trace and rare-earth elements, to enhance the calibration robustness. This expansion will encompass additional archaeological material typologies, such as mortars, plasters, and alloys from the Tindari site, in alignment with the ongoing SAMOTHRACE project. Furthermore, systematic studies will be conducted to assess the influence of the environmental variables on instrument performance and to benchmark h-LIBS against state-of-the-art techniques like pXRF. Finally, efforts will be made to optimize measurement protocols for real artifact surfaces, addressing surface roughness and microstructural heterogeneity to improve accuracy and reproducibility in situ.