Publications by authors named "Erika Ribechini"

38 Publications

A genome sequence from a modern human skull over 45,000 years old from Zlatý kůň in Czechia.

Nat Ecol Evol 2021 06 7;5(6):820-825. Epub 2021 Apr 7.

Max Planck Institute for the Science of Human History, Jena, Germany.

Modern humans expanded into Eurasia more than 40,000 years ago following their dispersal out of Africa. These Eurasians carried ~2-3% Neanderthal ancestry in their genomes, originating from admixture with Neanderthals that took place sometime between 50,000 and 60,000 years ago, probably in the Middle East. In Europe, the modern human expansion preceded the disappearance of Neanderthals from the fossil record by 3,000-5,000 years. The genetic makeup of the first Europeans who colonized the continent more than 40,000 years ago remains poorly understood since few specimens have been studied. Here, we analyse a genome generated from the skull of a female individual from Zlatý kůň, Czechia. We found that she belonged to a population that appears to have contributed genetically neither to later Europeans nor to Asians. Her genome carries ~3% Neanderthal ancestry, similar to those of other Upper Palaeolithic hunter-gatherers. However, the lengths of the Neanderthal segments are longer than those observed in the currently oldest modern human genome of the ~45,000-year-old Ust'-Ishim individual from Siberia, suggesting that this individual from Zlatý kůň is one of the earliest Eurasian inhabitants following the expansion out of Africa.
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http://dx.doi.org/10.1038/s41559-021-01443-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8175239PMC
June 2021

Molecular profiling of Peru Balsam reveals active ingredients responsible for its pharmaceutical properties.

Nat Prod Res 2020 Apr 21:1-6. Epub 2020 Apr 21.

Research Laboratory for Archaeology and the History of Art, University of Oxford, Oxford, UK.

Peru Balsam, a resinous substance derived from var. , has historically been used as a topical ointment for various skin conditions such as scabies, poorly healing wounds, eczema, and haemorrhoids. The ingredients responsible for these properties are not fully elucidated. We investigated the chemical composition of two Peru Balsam samples, one historical and one modern, using gas chromatography/mass spectrometry to identify the active ingredients responsible for its pharmaceutical properties. Both Peru Balsam specimens investigated had similar compositions, showing the stability of the substance. Components identified are effective against scabies, exhibit antimicrobial activity and aid skin penetration. These properties are consistent with historical uses of Peru Balsam. Several ingredients are also known allergens. This study, combining chemical information with scientific literature related to pharmaceutical properties of natural substances, represents a breakthrough in the elucidation of active ingredients in Peru Balsam.
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http://dx.doi.org/10.1080/14786419.2020.1753056DOI Listing
April 2020

Profiling of high molecular weight esters by flow injection analysis-high resolution mass spectrometry for the characterization of raw and archaeological beeswax and resinous substances.

Talanta 2020 May 31;212:120800. Epub 2020 Jan 31.

Department of Chemistry and Industrial Chemistry, Via Giuseppe Moruzzi 13, 56124, Pisa, Italy.

This work presents a method to characterize high molecular esters in beeswax and resinous substances based on the use of microwave-assisted extraction and flow injection analysis-high resolution mass spectrometry that combines the high efficiency of the extraction procedure with the advantages of high resolution mass spectrometry. This approach allows us to identify archaeological beeswax and plant resinous substances by the characterization of the survived intact high molecular weight components. By this way, several raw materials (beeswax, pine resin and pitch, and resin extracted from Euphorbia tirucalli) were studied and used as reference substances. The procedure was then tested on an adhesive dated 44-42 ka BP recovered from Border Cave (KwaZulu-Natal, Africa), allowing us to detect the high molecular weight species even after almost 50,000 years, and then used to chemically investigate unknown archaeological adhesives from Antinoopolis (Egypt), dated to the 4th-5th century AD. The results allowed us to extend our knowledge on the long-term behavior of beeswax and resinous substances.
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http://dx.doi.org/10.1016/j.talanta.2020.120800DOI Listing
May 2020

SIFT-ing archaeological artifacts: Selected ion flow tube-mass spectrometry as a new tool in archaeometry.

Talanta 2020 Jan 5;207:120323. Epub 2019 Sep 5.

Department of Chemistry and Industrial Chemistry, University of Pisa, Italy.

A fast non-destructive approach based on the use of portable selected ion flow tube-mass spectrometry (SIFT-MS) was used for the first time to characterize organic materials in archaeological artifacts. The high sensitivity, specificity and selectivity SIFT soft chemical ionization mass spectrometry enabled us to investigate the composition of organic residues collected from ancient Egyptian findings in order to demonstrate the robustness of the techniques with different matrices. In addition, we tested SIFT-MS directly on an archaeological Egyptian amphora to prove its suitability as a completely non-invasive technique. Parallel investigations on all the samples were performed by GC/MS analysis to correlate and confirm the data obtained by SIFT-MS. The possibility of using a portable mass spectrometer on an excavation site or in a museum would be a significant step forward in the non-invasive analysis of organic archaeological materials, enabling archeologists and conservators to obtain real-time information on the molecular composition of organic residues.
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http://dx.doi.org/10.1016/j.talanta.2019.120323DOI Listing
January 2020

Assessing the efficiency of supercritical fluid extraction for the decontamination of archaeological bones prior to radiocarbon dating.

Analyst 2019 Oct;144(20):6128-6135

Oxford Radiocarbon Accelerator Unit, RLAHA, University of Oxford, 1 South Parks Road, Oxford, OX1 3TG, UK.

Bone is one of the main sample types used for building chronologies in archaeology. It is also used in other research areas such as palaeodiet and palaeoenvironmental studies. However, for results to be accurate, samples must be free of exogenous carbon. Contamination can originate from a wide range of sources in the post-depositional environment but may also occur during excavation and post excavation activities (i.e. with the application of conservation materials) or during laboratory handling. Efficient procedures to remove contamination are therefore crucial prior to radiocarbon or stable isotope measurements. This work describes the development of an innovative sample pretreatment for bones, based on using supercritical CO2, which shows unique solvation properties. The effectiveness of supercritical fluid extraction (SFE) to remove conservation materials was compared with that obtained when applying a routine extraction based on the use of organic solvents (methanol, acetone and chloroform). The chemical composition of the bone samples before and after the two pre-treatments was then investigated using analytical pyrolysis-based techniques: EGA-MS (Evolved Gas Analysis-Mass Spectrometry) and Py-GC/MS (Pyrolysis-Gas Chromatography coupled with Mass Spectrometry). Collagen samples extracted from the same bones, prepared with the two cleaning protocols, were also radiocarbon dated by Accelerator Mass Spectrometry (AMS). The results of this study show that SFE is an efficient alternative method because it was as effective as the established treatment protocol. It removes contaminants such as conservation materials from bone samples with a minimum of handling and can be used routinely in radiocarbon dating laboratories. This work also demonstrates that analytical pyrolysis is not only a very efficient method to identify contaminants in bones but also to assess the effectiveness of the pretreatment prior to the radiocarbon measurement of the samples.
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http://dx.doi.org/10.1039/c9an00859dDOI Listing
October 2019

Compound-specific radiocarbon dating and mitochondrial DNA analysis of the Pleistocene hominin from Salkhit Mongolia.

Nat Commun 2019 01 30;10(1):274. Epub 2019 Jan 30.

Oxford Radiocarbon Accelerator Unit, Research Laboratory for Archaeology and the History of Art, University of Oxford, Dyson Perrins Building, South Parks Road, Oxford, OX1 3QY, UK.

A skullcap found in the Salkhit Valley in northeast Mongolia is, to our knowledge, the only Pleistocene hominin fossil found in the country. It was initially described as an individual with possible archaic affinities, but its ancestry has been debated since the discovery. Here, we determine the age of the Salkhit skull by compound-specific radiocarbon dating of hydroxyproline to 34,950-33,900 Cal. BP (at 95% probability), placing the Salkhit individual in the Early Upper Paleolithic period. We reconstruct the complete mitochondrial genome (mtDNA) of the specimen. It falls within a group of modern human mtDNAs (haplogroup N) that is widespread in Eurasia today. The results now place the specimen into its proper chronometric and biological context and allow us to begin integrating it with other evidence for the human occupation of this region during the Paleolithic, as well as wider Pleistocene sequences across Eurasia.
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http://dx.doi.org/10.1038/s41467-018-08018-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6353915PMC
January 2019

Olive mill wastewaters: quantitation of the phenolic content and profiling of elenolic acid derivatives using HPLC-DAD and HPLC/MS with an embedded polar group stationary phase.

Nat Prod Res 2019 Nov 10;33(21):3171-3175. Epub 2018 Oct 10.

Department of Chemistry and Industrial Chemistry, University of Pisa , Pisa , Italy.

Olive mill wastewaters (OMWs) are important by-products of olive oil production. The wide availability and the forbidding economic costs of OMWs disposal have generated interest in their possible exploitation as a sustainable source of polyphenols. The development and optimisation of improved analytical methods for the detailed characterisation of polyphenol molecular profiles after production and during storage conditions are thus required. A new analytical method based on reverse-phase HPLC separation of polyphenols in OMWs on an embedded-polar group (EPG) stationary phase is proposed as an alternative to conventional C18 columns. The procedure was used for the quantitation of 11 polyphenols, using diode-array detection (DAD), and achieving quantitation limits equal to or lower than 0.1 µg g. The same chromatographic set-up, coupled with high resolution tandem mass spectrometry (HPLC/ESI-Q-ToF), allowed us to identify hydroxytyrosyl esters of elenolic acid, whose relative abundance is proposed for monitoring the ageing of OMWs during storage.
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http://dx.doi.org/10.1080/14786419.2018.1522632DOI Listing
November 2019

Effect of ball-milling on crystallinity index, degree of polymerization and thermal stability of cellulose.

Bioresour Technol 2018 Dec 7;270:270-277. Epub 2018 Sep 7.

Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy. Electronic address:

A combined study of crystallinity index (CI), degree of polymerisation (DP) and thermal stability of cellulose was carried out for monitoring the effect of ball-milling. DP and CI are two fundamental quantities that describe the physico-chemical behaviour of cellulose. Milling is a common strategy to reduce cellulose crystallinity. In this work, four different commercially available celluloses were milled at 30, 60 and 120 min, and the changes in DP and CI were monitored using spectroscopic, diffraction and chromatographic techniques. Evolved gas analysis-mass spectrometry (EGA-MS) was also used to evaluate the changes in apparent activation energy (E) of the pyrolysis reaction upon different milling times by using model-free isoconversional methods. The results showed substantial decrease in CI values and moderate changes in DP after two-hours of ball-milling. E were found in the range 110-140 kJ/mol, and were reduced by 10% on average after two hours of ball-milling.
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http://dx.doi.org/10.1016/j.biortech.2018.09.029DOI Listing
December 2018

A comparison of fast and reactive pyrolysis with insitu derivatisation of fructose, inulin and Jerusalem artichoke (Helianthus tuberosus).

Anal Chim Acta 2018 Aug 13;1017:66-74. Epub 2018 Feb 13.

Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy. Electronic address:

Reactive pyrolysis is a technique that provides mechanistic information by performing pyrolysis of the substrate in a sealed glass capsule at elevated temperature and pressure for relatively long time. This technique has already shown great potential for the analysis of biomass, favouring the formation of only the most thermostable compounds. In this work, both fast and reactive pyrolysis with on-line gas chromatography-mass spectrometry analysis (Py-GC/MS) are used to study fructose, inulin and Jerusalem artichoke tubers (Heliantus tuberosus). Interesting differences were found between the two systems, and became even more evident as the reaction time was increased. The most striking result was the formation of di-fructose dianhydrides (DFAs), a class of compounds with interesting biological activities. DFAs were obtained in high yields from reactive pyrolysis, but not from fast pyrolysis. Hypotheses on the pyrolysis mechanisms were made based upon the composition of the pyrolysates. This work describes for the first time the behaviour of fructans under reactive pyrolysis.
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http://dx.doi.org/10.1016/j.aca.2018.02.019DOI Listing
August 2018

Recent Advances in Analytical Pyrolysis to Investigate Organic Materials in Heritage Science.

Angew Chem Int Ed Engl 2018 06 2;57(25):7313-7323. Epub 2018 May 2.

Department of Chemistry and Industrial Chemistry, Università di Pisa, via Moruzzi, 13, 56124, Pisa, Italy.

The molecular characterization of organic materials in samples from artworks and historical objects traditionally entailed qualitative and quantitative analyses by HPLC and GC. Today innovative approaches based on analytical pyrolysis enable samples to be analysed without any chemical pre-treatment. Pyrolysis, which is often considered as a screening technique, shows previously unexplored potential thanks to recent instrumental developments. Organic materials that are macromolecular in nature, or undergo polymerization upon curing and ageing can now be better investigated. Most constituents of paint layers and archaeological organic substances contain major insoluble and chemically non-hydrolysable fractions that are inaccessible to GC or HPLC. To date, molecular scientific investigations of the organic constituents of artworks and historical objects have mostly focused on the minor constituents of the sample. This review presents recent advances in the qualitative and semi-quantitative analyses of organic materials in heritage objects based on analytical pyrolysis coupled with mass spectrometry.
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http://dx.doi.org/10.1002/anie.201713404DOI Listing
June 2018

Antihyperlipidemic effect of a Rhamnus alaternus leaf extract in Triton-induced hyperlipidemic rats and human HepG2 cells.

Biomed Pharmacother 2018 May 22;101:501-509. Epub 2018 Mar 22.

Laboratoire de Biotechnologies Végétales et Ethnobotanique, Faculté des Sciences de la Nature et de la Vie, Université de Bejaia, 06000 Bejaia, Algeria.

The Mediterranean buckthorn, Rhamnus alaternus L., is a plant used in traditional medicine in Mediterranean countries. We aimed at characterizing its phenolic compounds and explore potential antihyperlipidemic activity of this plant. The profile of phenolic compounds in R. alaternus leaf crude methanolic extract (CME) and its liquid-liquid extraction-derived fractions were analyzed by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC/ESI-MS). Effects of CME on: circulating lipids in rats with Triton WR-1339-induced hyperlipidemia, intracellular lipid accumulation and expression of genes of fatty acid metabolism in human hepatoma HepG2 cells, and adipogenesis in the 3T3-L1 murine adipocyte cell model were assessed. The HPLC/ESI-MS analytical profile revealed a total of fifteen compounds, of which eleven were identified. Oral CME administration decreased blood levels of cholesterol and triacylglycerols in hyperlipidemic rats (by 60% and 70%, respectively, at 200 mg CME/kg). In HepG2 cells, CME exposure dose-dependently decreased intracellular lipids and up-regulated gene expression of carnitine palmitoyltransferase 1 involved in fatty acid oxidation. In the 3T3-L1 model, CME favored preadipocyte proliferation and adipogenesis, pointing to positive effects on adipose tissue expandability. These results suggest novel uses of R. alaternus by showing that its leaves are rich in flavonoids and flavonoid derivatives with an antihyperlipidemic effect in vivo and in hepatic cells.
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http://dx.doi.org/10.1016/j.biopha.2018.02.106DOI Listing
May 2018

Long-lasting ergot lipids as new biomarkers for assessing the presence of cereals and cereal products in archaeological vessels.

Sci Rep 2018 03 2;8(1):3935. Epub 2018 Mar 2.

Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via G. Moruzzi 13, 56124, Pisa, Italy.

Cereals were very important in ancient diets, however evidence from archaeological sites of the vessels used for processing or storing cereals is comparatively rare. Micro-organisms, as well as chemical-physical effects can easily degrade cereals during the burial period. This can lead to a complete cereal decay and to serious difficulties in estimating the intensity of use of the cereals by ancient populations. Here, we present a novel biomarker approach entailing the detection of secondary lipid metabolites produced by ergot fungi (genus Claviceps), which are common cereal pests. The aim was to identify the original presence of Gramineae and to indirectly establish if vessels were used for cereal storage/processing. The fatty acid and TAG-estolide profiles of the remains from more than 30 archaeological vessels were investigated by gas chromatography/mass spectrometry (GC/MS) and high performance liquid chromatography/high resolution mass spectrometry (HPLC/ESI-Q-ToF). The detection of lipids derived from ergot in archaeological and historic contexts rests on its complex chemistry, providing a unique and relatively recalcitrant chemical signature for cereals. This research demonstrated that the combination of our innovative biomarker approach along with environmental and archaeological evidence can provide unprecedented insights into the incidence of cereals and related processing activities in ancient societies.
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http://dx.doi.org/10.1038/s41598-018-22140-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5834523PMC
March 2018

In-depth characterization of valuable char obtained from hydrothermal conversion of hazelnut shells to levulinic acid.

Bioresour Technol 2017 Nov 7;244(Pt 1):880-888. Epub 2017 Aug 7.

Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124 Pisa, Italy. Electronic address:

For the first time, the exploitation of hazelnut shells for the combined production of levulinic acid (LA) and hydrochar was investigated. The optimization of the catalytic hydrothermal treatment was performed both in autoclave and microwave reactor, approaching a maximum LA yield of ∼9-12wt%. Hydrochars recovered with high yield (∼43-47wt%) were characterized by different techniques, including elemental and proximate analysis, heating value, FT-IR, XPS, XRD, SEM-EDX, and SAA. Their "lignite-like" energetic properties make them suitable for the energy recovery within the same biorefinery plant for LA production, thus partially offsetting the cost of the entire process. Alternatively, since the synthesized hydrochars maintain high levels of oxygenated groups, they could be smartly exploited as natural sorbents for environmental applications. The proposed integrated approach makes possible to fully exploit this waste, smartly closing its biorefinery cycle in a sustainable development perspective.
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http://dx.doi.org/10.1016/j.biortech.2017.08.012DOI Listing
November 2017

Analytical Approaches Based on Gas Chromatography Mass Spectrometry (GC/MS) to Study Organic Materials in Artworks and Archaeological Objects.

Top Curr Chem (Cham) 2016 Feb 4;374(1). Epub 2016 Jan 4.

Department of Chemistry and Industrial Chemistry, University of Pisa, Via Moruzzi 13, 56124, Pisa, Italy.

Gas chromatography/mass spectrometry (GC/MS), after appropriate wet chemical sample pre-treatments or pyrolysis, is one of the most commonly adopted analytical techniques in the study of organic materials from cultural heritage objects. Organic materials in archaeological contexts, in classical art objects, or in modern and contemporary works of art may be the same or belong to the same classes, but can also vary considerably, often presenting different ageing pathways and chemical environments. This paper provides an overview of the literature published in the last 10 years on the research based on the use of GC/MS for the analysis of organic materials in artworks and archaeological objects. The latest progresses in advancing analytical approaches, characterising materials and understanding their degradation, and developing methods for monitoring their stability are discussed. Case studies from the literature are presented to examine how the choice of the working conditions and the analytical approaches is driven by the analytical and technical question to be answered, as well as the nature of the object from which the samples are collected.
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http://dx.doi.org/10.1007/s41061-015-0007-xDOI Listing
February 2016

Timing in Analytical Pyrolysis: Py(HMDS)-GC/MS of Glucose and Cellulose Using Online Micro Reaction Sampler.

Anal Chem 2016 09 29;88(18):9318-25. Epub 2016 Aug 29.

Department of Chemistry and Industrial Chemistry, University of Pisa , via Giuseppe Moruzzi 13, I-56124, Pisa, Italy.

A novel analytical approach based on pyrolysis-gas chromatography coupled with mass spectrometry of carbohydrates with in situ silylation using hexamethyldisilazane is presented in this work for the first time. A micro reaction sampler was used to simultaneously achieve the pyrolyis reaction and facilitate the derivatization of pyrolysis products, by enabling the materials to react with the derivatizing agent in a sealed capsule at high temperature and pressure for long periods of time. This drastically increased the complete silylation of the pyrolysis products and the chromatographic resolution, resulting in less complex pyrograms and increased sensitivity toward the most stable compounds. Different results were obtained for glucose and cellulose in terms of predominant pyrolytic pathways. The formation of anhydrosugars was the preferential pyrolytic reaction for glucose, while the formation of cyclopentenones and small molecules was predominant for the pyrolysis of cellulose. Steric hindrance effects of polysaccharide chains on the efficiency of the derivatizing agent were hypothesized in order to explain the different results. A good reproducibility was found, with relative standard deviations not greater than 10%. Semiquantitative calculations showed that the partial silylation of anhydrosugars was almost completely overcome after 10 min of reactive pyrolysis. This work discloses a powerful and potentially widely applicable analytical method for the investigations of organic materials under controlled pyrolytic conditions, with the advantage of increasing the effectiveness of in situ derivatization.
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http://dx.doi.org/10.1021/acs.analchem.6b02910DOI Listing
September 2016

Monitoring/characterization of stickies contaminants coming from a papermaking plant--Toward an innovative exploitation of the screen rejects to levulinic acid.

Waste Manag 2016 Mar 3;49:469-482. Epub 2016 Feb 3.

Department of Chemistry and Industrial Chemistry, University of Pisa, Via Giuseppe Moruzzi 13, 56124 Pisa, Italy. Electronic address:

Recycled paper needs a lot of mechanical/chemical treatments for its re-use in the papermaking process. Some of these ones produce considerable rejected waste fractions, such as "screen rejects", which include both cellulose fibers and non-fibrous organic contaminants, or "stickies", these last representing a shortcoming both for the papermaking process and for the quality of the final product. Instead, the accepted fractions coming from these unit operations become progressively poorer in contaminants and richer in cellulose. Here, input and output streams coming from mechanical screening systems of a papermaking plant using recycled paper for cardboard production were sampled and analyzed directly and after solvent extraction, thus confirming the abundant presence of styrene-butadiene rubber (SBR) and ethylene vinyl acetate (EVA) copolymers in the output rejected stream and cellulose in the output accepted one. Despite some significant drawbacks, the "screen reject" fraction could be traditionally used as fuel for energy recovery within the paper mill, in agreement with the integrated recycled paper mill approach. The waste, which still contains a cellulose fraction, can be also exploited by means of the hydrothermal route to give levulinic acid, a platform chemical of very high value added.
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http://dx.doi.org/10.1016/j.wasman.2016.01.026DOI Listing
March 2016

Snapshots of lignin oxidation and depolymerization in archaeological wood: an EGA-MS study.

J Mass Spectrom 2015 Oct;50(10):1103-13

Department of Chemistry and Industrial Chemistry, University of Pisa, via Moruzzi 13, Pisa, I-56124, Italy.

Evolved gas analysis-mass spectrometry (EGA-MS) was used for the first time to study archaeological wood, in order to investigate its chemical degradation. The archaeological wood was from an oak pile from a stilt house found in the Neolithic 'La Marmotta' village (Lake Bracciano, Rome, Italy). The sampling was performed from the external to the internal part of the pile, following the annual growth rings in groups of five. In addition, sound oak wood and isolated wood components (holocellulose and cellulose) were also analyzed, and the results were used to highlight differences because of degradation. Our study demonstrated that EGA-MS provides information on the thermo-chemistry of archaeological wood along with in-depth compositional data thanks to the use of MS. Our investigations not only highlighted wood degradation in terms of differences between carbohydrates and lignin content, but also showed that lignin oxidation and depolymerization took place in the archaeological wood. Mass spectral data revealed differences among the archaeological samples from the internal to the external part of the pile. An increase in the formation of wood pyrolysis products bearing a carbonyl group at the benzylic position and a decrease in the amount of lignin dimers were observed. These were related to oxidation and depolymerization reactions, respectively.
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http://dx.doi.org/10.1002/jms.3631DOI Listing
October 2015

Field-emission scanning electron microscopy and energy-dispersive x-ray analysis to understand the role of tannin-based dyes in the degradation of historical wool textiles.

Microsc Microanal 2014 Oct 1;20(5):1534-43. Epub 2014 Jul 1.

1Dipartimento di Chimica e Chimica Industriale,Università di Pisa,via Risorgimento 35,56126 Pisa,Italy.

An innovative approach, combining field-emission scanning electron microscopy (FESEM) with energy dispersive X-ray spectroscopy (EDX) analysis, is presented to investigate the degradation mechanisms affecting tannin-dyed wool. In fact, tannin-dyed textiles are more sensitive to degradation then those dyed with other dyestuffs, even in the same conservation conditions. FESEM-EDX was first used to study a set of 48 wool specimens (artificially aged) dyed with several raw materials and mordants, and prepared according to historical dyeing recipes. EDX analysis was performed on the surface of wool threads and on their cross-sections. In addition, in order to validate the model formulated by the analysis of reference materials, several samples collected from historical and archaeological textiles were subjected to FESEM-EDX analysis. FESEM-EDX investigations enabled us to reveal the correlation between elemental composition and morphological changes. In addition, aging processes were clarified by studying changes in the elemental composition of wool from the protective cuticle to the fiber core in cross-sections. Morphological and elemental analysis of wool specimens and of archaeological and historical textiles showed that the presence of tannins increases wool damage, primarily by causing a sulfur decrease and fiber oxidation.
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http://dx.doi.org/10.1017/S1431927614012793DOI Listing
October 2014

Development and optimisation of an HPLC-DAD-ESI-Q-ToF method for the determination of phenolic acids and derivatives.

PLoS One 2014 14;9(2):e88762. Epub 2014 Feb 14.

Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Pisa, Italy.

A method for the HPLC-MS/MS analysis of phenols, including phenolic acids and naphtoquinones, using an amide-embedded phase column was developed and compared to the literature methods based on classical C18 stationary phase columns. RP-Amide is a recently developed polar embedded stationary phase, whose wetting properties mean that up to 100% water can be used as an eluent. The increased retention and selectivity for polar compounds and the possibility of working in 100% water conditions make this column particularly interesting for the HPLC analysis of phenolic acids and derivatives. In this study, the chromatographic separation was optimised on an HPLC-DAD, and was used to separate 13 standard phenolic acids and derivatives. The method was validated on an HPLC-ESI-Q-ToF. The acquisition was performed in negative polarity and MS/MS target mode. Ionisation conditions and acquisition parameters for the Q-ToF detector were investigated by working on collision energies and fragmentor potentials. The performance of the method was fully evaluated on standards. Moreover, several raw materials containing phenols were analysed: walnut, gall, wine, malbec grape, French oak, red henna and propolis. Our method allowed us to characterize the phenolic composition in a wide range of matrices and to highlight possible matrix effects.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088762PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3925170PMC
October 2014

Positive and negative-mode laser desorption/ionization-mass spectrometry (LDI-MS) for the detection of indigoids in archaeological purple.

J Mass Spectrom 2013 Mar;48(3):384-91

Department Chemistry and Industrial Chemistry, University of Pisa, via Risorgimento 35, 56126 Pisa, Italy.

Laser-based ionization techniques have demonstrated to be a valuable analytical tool to study organic pigments by mass spectrometric analyses. Though laser-based ionization techniques have identified several natural and synthetic organic dyes and pigments, they have never been used in the characterization of purple. In this work, positive and negative-mode laser desorption/ionization mass spectrometry (LDI-MS) was used for the first time to detect indigoids in shellfish purple. The method was used to study organic residues collected from archaeological ceramic fragments that were known to contain purple, as determined by a classical high-performance liquid chromatography-based procedure. LDI-MS provides a mass spectral fingerprint of shellfish purple, and it was found to be a rapid and successful tool for the identification of purple. In addition, a comparison between positive and negative mode ionization highlighted the complementarity of the two ionization modes. On the one hand, the negative-ion mode LDI-MS showed a better selectivity and sensitivity to brominated molecules, such as 6,6'-dibromoindigo, 6-monobromoindigo, 6,6'-dibromoindirubin, 6- and 6'-monobromoindirubin, thanks to their electronegativity, and produced simpler mass spectra. On the other hand, negative-ion mode LDI-MS was found to have a lower sensitivity to non-brominated compounds, such as indigo and indirubin, whose presence can be established in any case by collecting the complementary positive-ion LDI mass spectrum.
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http://dx.doi.org/10.1002/jms.3169DOI Listing
March 2013

Ingredients of a 2,000-y-old medicine revealed by chemical, mineralogical, and botanical investigations.

Proc Natl Acad Sci U S A 2013 Jan 7;110(4):1193-6. Epub 2013 Jan 7.

Soprintendenza per i Beni Archeologici della Toscana, 50143 Florence, Italy.

In archaeology, the discovery of ancient medicines is very rare, as is knowledge of their chemical composition. In this paper we present results combining chemical, mineralogical, and botanical investigations on the well-preserved contents of a tin pyxis discovered onboard the Pozzino shipwreck (second century B.C.). The contents consist of six flat, gray, discoid tablets that represent direct evidence of an ancient medicinal preparation. The data revealed extraordinary information on the composition of the tablets and on their possible therapeutic use. Hydrozincite and smithsonite were by far the most abundant ingredients of the Pozzino tablets, along with starch, animal and plant lipids, and pine resin. The composition and the form of the Pozzino tablets seem to indicate that they were used for ophthalmic purposes: the Latin name collyrium (eyewash) comes from the Greek name κoλλυρα, which means "small round loaves." This study provided valuable information on ancient medical and pharmaceutical practices and on the development of pharmacology and medicine over the centuries. In addition, given the current focus on natural compounds, our data could lead to new investigations and research for therapeutic care.
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http://dx.doi.org/10.1073/pnas.1216776110DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3557061PMC
January 2013

New insights into the ageing of linseed oil paint binder: a qualitative and quantitative analytical study.

PLoS One 2012 14;7(11):e49333. Epub 2012 Nov 14.

Dipartimento di Chimica e Chimica Ind., Università di Pisa, Pisa, Italy.

This paper presents an analytical investigation of paint reconstructions prepared with linseed oil that have undergone typical 19th century treatments in preparation for painting. The oil was mechanically extracted from the same seed lot, which was then processed by various methods: water washing, heat treatments, and the addition of driers, with and without heat. A modern process lead white (Dutch source, Schoonhoven) and a commercially available vine black were used as pigments. The reconstructions were prepared in 1999, and naturally aged from then onwards. We compared thermogravimetric analysis (TG), which yields macromolecular information, with gas chromatography-mass spectrometry (GC-MS) and direct exposure mass spectrometry (DEMS), which both provide molecular information. The study enabled us to quantitatively demonstrate, for the first time, that the parameters used to identify drying oils are deeply influenced by the history of the paint. In particular, here we show that the ratio between the relative amounts of palmitic and stearic acid (P/S), which is used as an index for differentiating between drying oils, is extremely dependent on the pigments present and the age of the paint. Moreover the study revealed that neither the P/S parameter nor the ratios between the relative amounts of the various dicarboxylic acids (azelaic over suberic and azelaic over sebacic) can be used to trace the sorts of pre-treatment undergone by the oil investigated in this study. The final results represent an important milestone for the scientific community working in the field, highlighting that further research is still necessary to solve the identification of drying oils in works of art.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0049333PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498153PMC
May 2013

First chemical evidence of royal purple as a material used for funeral treatment discovered in a Gallo-Roman burial (Naintré, France, third century AD).

Anal Bioanal Chem 2011 Oct 7;401(6):1739-48. Epub 2011 Jul 7.

Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Pisa, Italy.

Violet-purple residues collected from a Gallo-Roman burial dated back to the second half of the third century A.D. and excavated at Naintré (France) were chemically investigated by multi-analytical methodology involving the use of Raman spectroscopy, direct exposure-mass spectrometry (DE-MS) and high-performance liquid chromatography (HPLC-UV-visible). Little is known about funeral treatment and rituals during Roman times. Retrieving valuable information on these by chemical analysis of organic residues was thus a key aspect of this work. Analyses demonstrated the presence of the very precious purple colorant obtained from shellfish glands commonly known as Tyrian or royal purple and its exceptional preservation. Chemical investigation and archaeological evidence have shown that purple was widely spread after the deposition of the body for burial. These results are the earliest chemical evidence of purple colorant used during funeral rituals (not as textile dye) and enabled us to highlight new aspects of funeral practices in Roman times.
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http://dx.doi.org/10.1007/s00216-011-5217-7DOI Listing
October 2011

Discovering the composition of ancient cosmetics and remedies: analytical techniques and materials.

Anal Bioanal Chem 2011 Oct 3;401(6):1727-38. Epub 2011 Jun 3.

Dipartimento di Chimica e Chimica Industriale, University of Pisa, Pisa, Italy.

This article reviews the analytical techniques and procedures used in the study of ancient cosmetics, therapeutic chemicals, and remedies found in historical and archaeological sites. Well consolidated techniques based on molecular and atomic spectroscopy, for example FT-IR, Raman, SEM-EDX, and XRD, and analytical procedures based on high-performance chromatography and mass spectrometry, for example GC-MS and HPLC-MS are reviewed. The advantages of recently introduced techniques based on synchrotron radiation and on direct mass spectrometric techniques are also discussed. The possibility of extracting information about composition, preparation techniques, and the degradation processes of ancient cosmetics, pharmaceutics, and ritual balms is analysed by use of several case studies.
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http://dx.doi.org/10.1007/s00216-011-5112-2DOI Listing
October 2011

Gas chromatography/mass spectrometry and pyrolysis-gas chromatography/mass spectrometry for the chemical characterisation of modern and archaeological figs (Ficus carica).

J Chromatogr A 2011 Jun 28;1218(25):3915-22. Epub 2011 Apr 28.

Department of Chemistry and Industrial Chemistry, University of Pisa, Pisa, Italy.

Gas chromatography/mass spectrometry (GC/MS) after alkaline hydrolysis, solvent extraction and trimethylsilylation, and analytical pyrolysis using hexamethyldisilazane (HMDS) for in situ derivatisation followed by gas chromatographic/mass spectrometric analysis (Pyrolysis-silylation-GC/MS) were used to investigate the hydrolysable and soluble constituents, and the polymerised macromolecules of an archaeological fig (Ficus carica) recovered in Zaragoza (Spain), as well as of modern figs. The main aim was to study the compositional alterations undergone by the fig tissues in a particular archaeological environment: the fig was in a vessel and covered by a layer of a mixture of orpiment and gypsum. A comparison between the GC/MS results from modern and archaeological figs revealed that degradative reactions took place, leading to the disappearance/depletion of reactive (unsaturated fatty acids) and sensitive compounds (phytosterols and triterpenes). Py-silylation-GC/MS data provided evidence of a significant degradation of the saccharide and lipid components of the fig tissue, which left a residue enriched in polyphenols and polyesters.
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http://dx.doi.org/10.1016/j.chroma.2011.04.052DOI Listing
June 2011

Analytical strategies for characterizing organic paint media using gas chromatography/mass spectrometry.

Acc Chem Res 2010 Jun;43(6):715-27

Chemical Science for the Safeguard of the Cultural Heritage Group, Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, 56126 Pisa, Italy.

Throughout history, artists have experimented with a variety of organic-based natural materials, using them as paint binders, varnishes, and ingredients for mordants in gildings. Artists often use many layers of paint to produce particular effects. How we see a painting is thus the final result of how this complex, highly heterogeneous, multimaterial, and multilayered structure interacts with light. The chemical characterization of the organic substances in paint materials is of great importance for artwork conservation because the organic components of the paint layers are particularly subject to degradation. In addition, understanding the organic content and makeup of paint materials allows us to differentiate between the painting techniques that have been used over history. Applying gas chromatography/mass spectrometry (GC/MS) analysis to microsamples of paint layers is widely recognized as the best approach for identifying organic materials, such as proteins, drying oils, waxes, terpenic resins, and polysaccharide gums. The method provides essential information for reconstructing artistic techniques, assessing the best conditions for long-term preservation, and planning restoration. In this Account, we summarize the more common approaches adopted in the study of the organic components of paint materials. Our progress in developing GC/MS analytical procedures in the field of cultural heritage is presented, focusing on problems that arise from (i) the presence of mixtures of many chemically complex and degraded materials, (ii) the interference of inorganic species, (iii) the small size of the samples, and (iv) the risk of contamination. We outline some critical aspects of the analytical strategy, such as the need to optimize specific wet-chemical sample pretreatments in order to separate the various components, hydrolyze macromolecular analytes, clean-up inorganic ions, and derivatize polar molecules for subsequent GC/MS separation and identification. We also discuss how to interpret the chromatographic data so as to be able to identify the materials. This identification is based on the presence of specific biomarkers (chemotaxonomy), on the evaluation of the overall chromatographic profile, or on the quantitative analysis of significant compounds. GC/MS-based analytical procedures have for 20 years provided important contributions to conservation science, but challenges and opportunities still coexist in the field of organic-based paint materials. We give selected examples and provide case studies showing how a better understanding of the chemical composition of organic paint materials and of their degradation pathways contribute to a better knowledge our cultural heritage, and to its preservation for future generations.
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http://dx.doi.org/10.1021/ar900185fDOI Listing
June 2010

Characterisation of archaeological waterlogged wood by pyrolytic and mass spectrometric techniques.

Anal Chim Acta 2009 Nov 8;654(1):26-34. Epub 2009 Jul 8.

Department of Chemistry and Industrial Chemistry, University of Pisa, via Risorgimento 35, I-56126 Pisa, Italy.

Two techniques based on analytical pyrolysis and mass spectrometry, direct exposure-MS (DE-MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), were used to characterise waterlogged archaeological wood and to study degradation patterns of wood in aqueous environments. The two techniques were applied to samples from the excavation of the Site of the Ancient Ships of Pisa San Rossore in Pisa (Italy), and data were compared to those relative to native sound wood of the same species (pine, elm, beech). Both the methods result valuable in the analysis of ancient wood artefacts, avoiding the long wet-chemical procedures that are commonly used in wood analysis, and allowing us to use a minimal sample size. DE-MS achieves a global mass spectral fingerprint of lignin and polysaccharides pyrolysis compounds in few minutes, and the results have been interpreted with the support of principal component analysis (PCA) of mass spectra. Py-GC/MS permits detailed molecular analysis of pyrolysis compounds and highlights some chemical modifications of lignin in archaeological samples, as demethylation of both guaiacyl and syringyl lignin units. Both the techniques demonstrate consistent loss of polysaccharides in archaeological wood.
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http://dx.doi.org/10.1016/j.aca.2009.07.007DOI Listing
November 2009

Chemical investigation on black pigments in the carved decoration of sixteenth century alabaster tombs from Zaragoza (Spain).

Anal Bioanal Chem 2009 Dec;395(7):2191-7

Instituto Universitario de Investigación en Ciencias Ambientales de Aragón (IUCA), Department of Analytical Chemistry, Faculty of Sciences, University of Zaragoza, 50009 Zaragoza, Spain.

An analytical protocol based on optical microscopy (OM), scanning electron microscopy (SEM) observation, energy-dispersive X-ray (EDX) analyses, analytical pyrolysis in the presence of hexamethyldisilazane followed by gas chromatographic/mass spectrometric analysis (Py-silylation-GC/MS) and gas chromatography/mass spectrometry (GC/MS) after alkaline hydrolysis, solvent extraction and trimethylsilylation was used to study the origin and nature of black pigments from the carved inscriptions of several panels of two alabaster tombs dated from the mid-sixteenth century. Optical microscopy and SEM observation showed the presence of an amorphous very dark-brown substance, from translucent to opaque. EDX analyses revealed that the samples were mainly made up of C and O, thus highlighting the organic nature of the material used in the inscriptions. Py-silylation-GC/MS and GC/MS analyses provided detailed molecular compositions, highlighting the presence of a wide range of compound classes including diterpenoid acids, tricyclic abietanes, mid- and long-chain monocarboxylic fatty acids, n-alkanols and nalkanes. The pyrograms, the chromatographic profiles and the presence of characteristic biomarkers indicated that a mixture of pine pitch and beeswax had been used to make the black inscriptions.
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http://dx.doi.org/10.1007/s00216-009-2977-4DOI Listing
December 2009

Py-GC/MS, GC/MS and FTIR investigations on Late Roman-Egyptian adhesives from opus sectile: new insights into ancient recipes and technologies.

Anal Chim Acta 2009 Apr 11;638(1):79-87. Epub 2009 Feb 11.

Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via Risorgimento 35, 56126 Pisa, Italy.

An analytical protocol based on optical microscopy, Fourier transforms infrared spectroscopy (FTIR), analytical pyrolysis in the presence of hexamethyldisilazane followed by gas chromatographic/mass spectrometric analysis (Py-GC/MS) and gas chromatography/mass spectrometry after alkaline hydrolysis, solvent extraction and trimethylsilylation (GC/MS) was used in the chemical characterisation of the original adhesives used to fix monochrome and mosaic glass and stone plaques coming from the Late Roman archaeological site of Antinoopolis (Egypt). FTIR analysis demonstrated the presence of calcite fragments, and Py-GC/MS and GC/MS analyses provided detailed molecular compositions, highlighting the presence of a wide range of compound classes including diterpenoid acids, tricyclic abietanes with a high degree of aromatisation, mid- and long-chain monocarboxylic fatty acids, mono- and di-hydroxy acids, alpha,omega-dicaboxylic fatty acids, n-alkanols, and n-alkanes. Characteristic biomarkers and their distribution patterns indicated the presence of pine pitch in all the adhesives, which in some cases was admixed with beeswax and brassicaceae seed oil. The results provided new insights into the complex recipes used by artisans in ancient Egypt in the production of adhesives and in the sophisticated manufacture of opus sectile decorations.
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http://dx.doi.org/10.1016/j.aca.2009.02.004DOI Listing
April 2009

An integrated analytical approach for characterizing an organic residue from an archaeological glass bottle recovered in Pompeii (Naples, Italy).

Talanta 2008 Jan 28;74(4):555-61. Epub 2007 Jun 28.

Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, 56126 Pisa, Italy.

Within the framework of an Italian research project aimed at studying organic residues found in archaeological objects from the Roman period, the chemical composition of the contents of several glass vessels recovered from archaeological sites from the Vesuvian area (Naples, Italy) was investigated. In particular, this paper deals with the study of an organic material found in a glass bottle from the archaeological site of Pompeii using a multi-analytical approach, including FT-IR, direct exposure mass spectrometry (DE-MS) and GC-MS techniques. The overall results suggest the occurrence of a lipid material of vegetable origin. The hypothesis that the native lipid material had been subjected to a chemical transformation procedure before being used is presented and discussed.
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http://dx.doi.org/10.1016/j.talanta.2007.06.026DOI Listing
January 2008