In this study, physico-mechanical properties and durability of 4 onyx-travertines from Sinincay (Ecuador) were investigated. These onyx-travertines are commonly used for decorative purposes in buildings in the Historic Center of Santa Ana de los Ríos de Cuenca. The aim of this work was to characterize these stones and determine the variation of their physico-mechanical properties, such as mass loss and water absorption, after being subjected to four durability tests: salt crystallization (S-C), freeze–thaw (F-T), thermal shock (T-S) and acid attack (A-A). In addition, Scanning Electron Microscopic (SEM) analyses were carried out to record weathering patterns and understand the deterioration mechanism. Results show that these stones’ sedimentary structure is stratified. Two specimens exhibit geometrical features consistent with porous laminated facies and the remaining two have slightly porous cryptolaminated ones. Facies’ structure orientation is also found to determine mechanical strength, exhibiting the normal to lamination orientation the lowest value. As for durability, the statistical interpretation of the results suggests that the level of severity of each test follows S-C > F–T > A-A > T-S. In addition, laminated facies are more vulnerable to accelerated aging tests. Impact of S-C, F–T and T-S tests is mainly explained by differences in porosity and damage produced by A-A is related to the available effective area for the reaction to take place. Thus, the onyx-travertine is more than a wonderful material, it represents an interesting case study for development of future research on heritage stone in Ecuador and the world by employing normalized tests that are rarely used or published.

Within the realm of archaeology, the analysis of biomolecules assumes significant importance in elucidating historical dietary patterns and their implications for contemporary contexts. To achieve this, knowledge and tools of both chemistry and archaeology are essential to yield objective outcomes and conduct analyses of archaeological materials for the detection of biomolecules. Usually, only minuscule remnants of ceramic fragments are retrieved from excavations, which limits the feasibility of comprehensive laboratory analysis. This study aimed to establish a protocol for analyzing fatty acids and starch from archaeological food utensils with minimal sample quantities. Various experiments were conducted to replicate preparations that might have occurred in archaeological vessels, aiming to establish the optimal protocol. The analyses were performed using clay griddles, subjecting vegetable oil to varying temperatures for fatty acid assessment. For starch analysis, a series of experiments encompassed diverse forms of potato preparations (pulp, chuño, tortilla, carbonization, and freeze-drying) and maize (flour, tortilla, and carbonization). The verification of the experiments was confirmed by conducting identical analyses, as developed in the current study, on authentic archaeological fragments. The principal outcomes of this investigation include the successful extraction of both types of biomolecules using only 0.25 g of the sample, obtained through direct scraping from the vessel. Soxhlet extraction was identified as the most efficient strategy to recover fatty acids. Additionally, a comprehensive protocol for the identification of starch extraction was developed. This study has, for the first time, elucidated two detailed methodologies for the extraction of fatty acids and starch in scenarios in which researchers can obtain limited quantities of archaeological food utensil fragments.

Ceramic brick as a building material is used in many civilizations worldwide. In the case of the Historic Center of Cuenca (Ecuador), it dates back to colonial times and remains as a determining factor in local identity. However, beyond the productive tradition, its technical conditions of knowledge, use, and conservation are limited. In this context, the present research resorts to analytical techniques to characterize the raw material and solid brick from historical production and historical supply sites. It is determined that there are significant variations in composition, physical and mechanical behavior and durability. Thus, the low compressive strength (x̄ = 5,87 MPa) and low bending strength (x̄ = 0,13 MPa), high open porosity (36–37 %) and water absorption (17–20 %), open an important discussion on the conservation conditions of the numerous heritage buildings built in brick, as well as on the implications for the artisanal production process.

Improving the absorption of visible light in photocatalysts could enhance photocatalytic reactions and reduce energy consumption, particularly in sunny regions like Ecuador. This study reports the synthesis of ZnO and ZnO nanoparticles doped with 1.5 at.% Er, 5 at.% Al, and 1.5 at.% Er, 5 at.% Al using the sol–gel method. The effect of doping on the structure, morphology, absorption spectra, and photocatalytic properties was analyzed by XRD, SEM, EDS, and UV-Vis spectrophotometry. XRD confirmed the presence of the wurtzite ZnO structure, and UV-Vis diffuse reflection spectra showed a red shift in the band gap for doped ZnO compared to pristine ZnO. Photocatalytic activity was evaluated through the degradation of methyl orange (MO) under artificial visible light and natural sunlight in Quito, Ecuador. ZnO doped with Er/Al nanoparticles exhibited significantly enhanced photocatalytic performance under solar light, suggesting the potential for replacing artificial light and reducing operating costs in photocatalytic processes. Moreover, all doped samples retained the antibacterial properties of ZnO against B. subtilis, and Er/Al co-doping improved the inhibition of E. coli compared to undoped ZnO.

Scientific studies concerning the causes and consequences of the biodeterioration of stone monuments located at high altitudes in permanently cold, mountainous regions are scarce. For that reason, this study aimed to detect and identify the bacteria involved in the deterioration of this type of monument. To achieve this goal, we focused on the most important archeological Inca site in the Ecuadorian Andes: Ingapirca’s Temple of the Sun, built approximately 500 years ago at 3.100 m.a.s.l. We first examined the stone surfaces of the temple by scanning electron microscopy and showed the detrimental impact on the mineral structure of the green andesite mineral used to build the temple, caused by crustose lichen thalli and heterotrophic bacteria. Then, we isolated, characterized, and identified several of these bacteria. Most of them multiplied at a wide range of temperatures, from 4 °C to 30 °C, and were thus considered eurypsychrophiles. Actinobacteria and Proteobacteria species dominated the culturable fraction of this community. Several isolates produced metabolites that solubilized mineral phosphates at low temperatures; others solubilized iron-containing mineral fractions in the green andesite rock when tested in vitro. To the best of our knowledge, this is the first report related to the biodeterioration of an Inca monument at such an altitude in the Andes range.

Choirbooks are historical heritage manuscripts used for the performance of vocal music in religious ceremonies in colonial times. This study aimed to understand the characteristics of choirbook manuscripts produced in the Real Audiencia de Quito during the 17th century. The methodology combined non-invasive techniques, such as infrared false-color imaging (IRFC) and X-ray fluorescence (XRF), together with spot analysis by scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX) and Fourier transform infrared spectroscopy with attenuated total reflection (FTIR-ATR). The analytical results revealed the use of pumice, chalk and lime carbonate as support materials in the manufacturing process and surface treatment of the parchment. In the illuminations, three pictorial techniques based on protein, polysaccharide and lipid binders were recognized, establishing that the pigments used with greater regularity in the illuminations were vermilion, minium, verdigris, orpiment, azurite, and indigo, preferably in a pure state. Materials used less regularly were also identified, such as yellow ochre, saffron, smalt, red ochre, and bone black, among others. Regarding the vulnerability of the pictorial materials, it was determined that, although most of the pigments exhibit chemical stability, they present some vulnerabilities associated with their intrinsic composition and the medium that contains them.