Application of a multi-analytical toolset to a 16th century ointment: Identification as lead plaster mixed with beeswax

Synthesis and Characterization of Maleic Anhydride-Methyl Methacrylate Co-Monomer Grafted Polyethylene Wax for Hot Waxed Wood Process

The beeswax used in Chinese traditional hot waxed wood technology has several drawbacks, such as high price, scarce resources, and poor heat resistance. To expand the application of hot waxing technology in the field of wood decoration and protection, polyethylene wax was modified by a grafted maleic anhydride-methyl methacrylate co-monomer. A type of modified polyethylene wax with low cost, high melting point, high stability, and strong polarity suitable for hot waxed wood was prepared as a replacement for beeswax. The effects of the grafting conditions on the chemical properties, thermal properties, chemical structure, and crystallization properties of modified polyethylene wax were studied and compared to those of beeswax. The results show that maleic anhydride-methyl methacrylate co-monomer grafting can effectively improve the acid value of polyethylene wax. For the ratio of two monomers of 1/1, the total amount of monomer of 8 wt%, the amount of initiator of 2 wt%, the reaction temperature of 150 °C, and the acid value of modified polyethylene wax was consistent with that of beeswax, realizing the simulation of the main chemical properties of beeswax. The thermal stability and melting temperature of the modified polyethylene wax are significantly higher than those of beeswax, its crystal structure is similar to that of beeswax, and the cyclic anhydride groups and ester groups introduced by co-monomer grafting endow it with polar groups that play an important role in the wood hot waxing process.

Recipes of Ancient Egyptian kohls more diverse than previously thought

Kohl, a dark eye cosmetic, is a well-known part of Ancient Egyptian culture. Modern chemical analyses of kohls have largely found lead-based inorganic constituents, whereas earlier studies argued for a much broader range of constituents. Furthermore, organic materials in kohls remain severely understudied. This raises questions regarding the true diversity of materials and recipes used to produce kohls. We analysed the contents of 11 kohl containers from the Petrie Museum collection in London. The objects selected cover a broad range of times and locations in Egypt. Our multi-analytical approach allowed us to characterise both inorganic and organic components. Our data show that inorganic ingredients in kohl recipes are not only lead-based but also manganese- and silicon-based. Our analyses also revealed that organic ingredients derived from both plant and animal sources were commonly used in kohl recipes and sometimes even represent the main constituent. All these findings point towards more varied recipes than initially thought and significantly shift our understanding of Ancient Egyptian kohls.

Bee products in the prehistoric southern levant: evidence from the lipid organic record

Beehive products have a rich global history. In the wider Levantine region, bees had a significant role in Egypt and Mesopotamia, and intensive beekeeping was noted in Israel during the Biblical period when apiaries were first identified. This study investigates the origins of this extensive beekeeping through organic residue analysis of pottery from prehistoric sites in the southern Levant. The results suggest that beehive products from likely wild bees were used during the Chalcolithic period as a vessel surface treatment and/or as part of the diet. These functions are reinforced by comparison to the wider archaeological record. While the true frequency of beeswax use may be debated, alternatives to beehive products were seemingly preferred as wild resources contrasted with the socio-economic system centred on domesticated resources, controlled production and standardization. Bee products only became an important part of the economic canon in the southern Levant several millennia later.

Liquid chromatography and mass spectrometry for the analysis of acylglycerols in art and archeology

Lipid characterization in art and archeology, together with the study of lipid degradation processes, is an important research area in heritage science. Lipid-based materials have been used as food since ancient times, but also employed as illuminants and as ingredients in cosmetic, ritual, and pharmaceutical preparations. Both animal and plant lipids have also been processed to produce materials used in art and crafts, such as paint binders, varnishes, waterproofing agents, and coatings. Identifying the origin of the lipid materials is challenging when they are found in association with artistic historical objects. This is due to the inherent complex composition of lipids, their widespread occurrence, and the chemical alterations induced by ageing. The most common approach for lipid characterization in heritage objects entails profiling fatty acids by gas chromatography/mass spectrometry after saponification or transesterification. New developments in high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) for the characterization of acylglycerols, together with more efficient sample treatments, have fostered the introduction of liquid chromatography for characterizing the lipid profile in heritage objects. This review reports the latest developments and applications of HPLC-MS for the characterization of lipid materials in the field of heritage science. We describe the various approaches for sample pretreatment and highlight the advantages and limitations of HPLC-MS in the analysis of paint and archeological samples. © 2020 John Wiley & Sons Ltd.

Smart edible coating films based on chitosan and beeswax-pollen grains for the postharvest preservation of Le Conte pear

Smart edible coating films can be used in food packaging. For this application, they must have good physical and mechanical properties. Herein, chitosan–beeswax based film is used to preserve Le Conte pears postharvest. The chitosan–beeswax films were characterized using XRD, FT-IR, and SEM analysis. Moreover, all films showed good self-healing aptitudes ranging from 86.7 to 96.3. The film treated with pollen grains showed an enhanced water contact angle compared with the chitosan film. The chitosan–beeswax/pollen grain film exhibited a two-fold lower WVTR value compared to the chitosan film, and showed the tendency to increase the stiffness of the film. The elongation% at break was reduced from 35.81 to 14.09. Fruit quality parameters were determined in cold storage for 105 days during shelf life after a simulated marketing period of 7 days. All coated fruits successfully showed decrease in weight loss, decay and rate of softening. Therefore, chitosan–beeswax/pollen grains can be considered safe and effective coating for the fruit preservation.

Smart edible coating films can be used in food packaging.

Disclosing the composition of unknown historical drug formulations: an emblematic case from the Spezieria of St. Maria della Scala in Rome

This paper reports a pioneering study of an unknown historical drug formulation preserved in the Spezieria of Santa Maria della Scala in Rome, founded at the end of the seventeenth century by the Discalced Carmelites. Due to limited literature related to pharmaceutical remedies and drugs of the Early Modern Era (between the XV and XVIII centuries) and the complexity in their formulations, the study of these drugs represents a great challenge. The untargeted nature of the selected drug required a multi-analytical approach with complementary techniques to formulate a compositional hypothesis: FT-IR spectroscopy, gas chromatography-associated/mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) were successfully employed to identify different organic compounds. Systematic archaeobotanical research was performed as well, allowing us to acquire data related to the possible genus of plants from which these natural compounds derive and their geographical origin. The unknown drug formulation turned out to be a complex mixture used as an ointment with an anti-inflammatory purpose. It mainly contains a mixture of Venetian turpentine; a Pine resin (colophony) from the Pinaceae family; an exudate of a plant from South America, whose identified components are triterpenic compounds such as alpha- and beta-amyrins, betulin and lupeol; and saturated fatty acids which act as carriers and/or to reduce the viscosity of abovementioned exudates and resins. The study of historical drugs is important not only in order to know the practices handed down by the speziali in the past but also to reconstruct historical recipes, which can inspire new dermatological, cosmetic, hygienic and current healing products.Graphical abstract.

A comparative study on the artificial UV and natural ageing of beeswax and Chinese wax and influence of wax finishing on the ageing of Chinese Ash (Fraxinus mandshurica) wood surfaces

This study investigated and compared the behaviour of two types of natural waxes, beeswax and Chinese wax, by means of two different ageing tests: an artificial accelerated ageing test using UV light and a simulated natural ageing test (indoors conditions) based on the action of natural, window-filtered light. The same tests were employed to evaluate the influence of wax finishing on the ageing behaviour of Chinese Ash (Fraxinus mandshurica) wood surfaces. Ageing effects were evaluated by direct and microscopic observation, colour measurements in the CIELab system and FTIR investigations. The results yielded by both accelerated UV ageing (72 h) and simulated indoors natural ageing (6 months) indicate that the waxes under analysis here are materials with a good ageing resistance. FTIR investigation revealed only minor chemical changes following ageing, more evident with beeswax than with Chinese wax. Finishing Chinese Ash wood surfaces with the two types of waxes influenced their ageing behaviour in terms of colour and surface chemistry changes. For both UV and natural ageing the maximum colour differences occurred for the samples finished with Chinese wax. The colour differences ΔE after 72 h accelerated UV ageing were in all the cases higher than those occurring after 6 months of indoors simulated natural ageing. Acceleration indexes for UV exposure compared to exposure to natural window-filtered sunlight, of about 40X-60X, were calculated. Both UV accelerated ageing and natural simulated ageing resulted in significant surface chemistry changes for the unfinished Chinese ash wood samples, consisting mostly in lignin degradation and formation of carbonyl containing chromophores. FTIR investigation of wax finish wood samples revealed only very minor chemical changes of the top wax layers, although chemical changes occurring beneath the coating layer on the wood surface are highly probable. Overall, the experiments presented in this paper indicate that Chinese wax seems slightly more resistant to ageing than beeswax.

Analytical studies of the Alexandrovo Thracian tomb wall paintings

A profound study of samples obtained from Thracian tomb wall paintings at Alexandrovo, Bulgaria (dating back to the fourth century BC) were carried out by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and Attenuated Total Reflectance Fourier transform infrared spectroscopy (ATR FTIR), high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDS). The current work provides a glimpse of the ingenious construction and painting techniques used in Thracian tomb at Alexandrovo. The results suggest that beeswax was used as a paint binder and also revealed presence of various nano-materials.