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1.
The technique of Raman microscopy has been used to identify and characterise the pigments used in red shards of medieval and earlier items of pottery which have been found in various archaeological sites in the South of Italy. The research has led to the identification, on the basis of their characteristic Raman/resonance Raman spectra, of the red pigments as iron(III) oxide (e.g. Indian Red, Red Ochre or Venetian Red) and the yellow pigments as hydrated iron(III) oxyhydroxide (e.g. Yellow Ochre and Mars Yellow). X-ray powder diffraction experiments confirm the conclusions drawn above. 相似文献
2.
P. Bruno M. Caselli M. L. Curri A. Genga R. Striccoli A. Traini 《Analytica chimica acta》2000,410(1-2):193-202
Chemical characterisation has been carried out on 58 fragments of archaeological pottery from pre-classical sites in Apulia and Lucania, regions in southern Italy. Fourteen elements were determined by atomic emission spectroscopy by using inductively coupled plasma source. Statistical techniques, such as principal component analysis and clustering analysis, have been utilised to define grouping of different pottery items. Tests performed showed that the analysed shards were differentiable mainly by age and provenance. 相似文献
3.
Lucilla Fabrizi Lorenzo Nigro Federico Cappella Federica Spagnoli Michele Guirguis Ana Maria Niveau de Villedary y Marias María Teresa Domnech‐Carb Caterina De Vito Antonio Domnech‐Carb 《Electroanalysis》2020,32(2):258-270
Solid state electrochemistry based on the voltammetry of immobilized microparticles (VIMP) methodology is applied to a series of 80 Phoenician Red Slip samples from the archaeological sites of Motya (Sicily, Italy), Mogador (Morocco), Ramat‐Rahel (Israel), Sulky (Sardinia, Italy), Tas Silg (Malta), Pantelleria (Italy), and Cádiz (Spain), dated from the 8th to the 6th century BC. Upon attachment of sub‐microsamples to graphite electrodes in contact with aqueous H2SO4 electrolyte, voltammetric features due to the reduction of Fe(III) minerals and the oxidation of Fe(II) ones, complemented with electrocatalytic effects on oxygen reduction and oxygen evolution reactions, provide characteristic electrochemical fingerprints for pottery samples. A consistent sample grouping discriminating between different potteries from different archaelogical sites, is obtained, all results being consistent with morphological, compositional and mineralogical data. Petrographic analysis supports the grouping, defining the manufacture and firing procedure for the different archaeological context. 相似文献
4.
Legodi MA de Waal D 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2007,66(1):135-142
The technique of Raman spectroscopy was used to examine the composition of ancient African domestic clay pottery of South African origin. One sample from each of four archaeological sites including Rooiwal, Lydenburg, Makahane and Graskop was studied. Normal dispersive Raman spectroscopy was found to be the most effective analytical technique in this study. XRF, XRD and FT-IR spectroscopy were used as complementary techniques. All representative samples contained common features, which were characterised by kaolin (Al2Si2O5(OH)5), illite (KAl4(Si7AlO20)(OH)4), feldspar (K- and NaAlSi3O8), quartz (alpha-SiO2), hematite (alpha-Fe2O3), montmorillonite (Mg3(Si,Al)4(OH)2 x 4.5 5H(2)O[Mg]0.35), and calcium silicate (CaSiO3). Gypsum (CaSO4 x 2H2O) and calcium carbonates (most likely calcite, CaCO3) were detected by Raman spectroscopy in Lydenburg, Makahane and Graskop shards. Amorphous carbon (with accompanying phosphates) was observed in the Raman spectra of Lydenburg, Rooiwal and Makahane shards, while rutile (TiO(2)) appeared only in Makahane shard. The Raman spectra of Lydenburg and Rooiwal shards further showed the presence of anhydrite (CaSO4). The results showed that South African potters used a mixture of clays as raw materials. The firing temperature for most samples did not exceed 800 degrees C, which suggests the use of open fire. The reddish brown and grayish black colours were likely due to hematite and amorphous carbon, respectively. 相似文献
5.
Red and white painting layers from Celtic pottery from Southern Poland (Modlniczka 2 site near Kraków) were investigated with the use of Raman microspectroscopy, SEM/EDS and optical microscopy. The painting layers were performed homogeneously for all the examined shards, i.e. red layers as thinner, ca. 0,02 mm and white of 0,04 mm. The white painting layers are very fine grained and amorphous under SEM, prepared of compositionally complex magnesium based raw material, with phosphates and fluorite probably used as fluxes. Unusual phases: fluorite and silicon were identified. Raman spectroscopy of fine grained red painting layers revealed the presence of hematite and anatase/leucoxen. Again, rare phases, of silicon and destinezite were found. Both paints were carefully manufactured by grinding and homogenizing the raw materials. Their preliminary firing cannot be excluded. The painted pottery was fired approx. at 700–900 °C, but multistage firing is possible. 相似文献
6.
Distributions of erythro and threo dihydroxy acids, extracted from ‘bound’ forms of organic residues preserved in archaeological pottery cooking vessels are shown to be the direct products from Z-monounsaturated alkenoic acids present in the original commodities, and are useful biomarkers for detecting marine animal product processing/consumption by ancient people. 相似文献
7.
Roberto Iglesias Rodríguez Manuel Fernández Delgado Julia Barciela García Rosa María Peña Crecente Sagrario García Martín Carlos Herrero Latorre 《Analytical and bioanalytical chemistry》2010,397(6):2603-2614
This paper has a double objective. The first goal was to develop an authentication system to differentiate between traditional
orujo alcoholic distillates with and without a certified brand of origin (CBO). Owing to their low price and quality, samples without
a CBO can be used as substrates for falsification of genuine CBO ones. The second objective was to perform a comparison of
the abilities of the different chemometric procedures employed for this classification. The classification was performed on
the basis of the chemical information contained in the metal composition of the orujo distillates. Eight metals determined by electrothermal atomic absorption spectrometry and inductively coupled plasma optical
emission spectrometry were considered (Ca, Cd, Cr, Cu, K, Mg, Na and Ni). After the appropriate pretreatment, the data were
processed using different chemometric techniques. In the first stage, principal component analysis and cluster analysis were
employed to reveal the latent structure contained in the data. Once it had been demonstrated that a relation exists between
the metal composition and the raw materials, and not between the metal composition and the distillation systems employed for
the orujo production, the second step consisted in the comparative application of different supervised pattern recognition procedures
(such as linear discriminant analysis, K-nearest neighbours, soft independent modelling of class analogy, UNEQ and different artificial neural network approaches,
including multilayer feed-forward, support vector machines, learning vector quantization and probabilistic neural networks).
The results showed the different capabilities of the diverse classification techniques to discriminate between Galician orujo samples. The best results were those provided by probabilistic neural networks, in which the correct recognition abilities
for CBO classes and without CBO classes were 98.6 ± 3.1 and 98.0 ± 4.5%; the prediction results were 87.7 ± 3.3 and 86.2 ± 5.0%,
respectively. The usefulness of chemical metal analysis in combination with chemometric techniques to develop a classification
procedure to authenticate Galician CBO orujo samples is demonstrated. 相似文献
8.
CdS aerogels: Effect of concentration and primary particle size on surface area and opto-electronic properties 总被引:1,自引:0,他引:1
Porous aerogels of CdS that exhibit quantum confined optical properties have been prepared by supercritical drying of wet
CdS gels prepared by oxidative stripping of nanoparticle capping groups. The water-to-surfactant ratio (W) employed in the
preparation of the nanoparticles is found to have a large impact on the surface areas of resultant aerogels, with W=5 samples producing mesoporous samples with the highest surface areas and cumulative pore volumes. In contrast, the concentration
of the CdS sol employed in the gelation has only a small effect on the porosity characteristics, but a large impact on the
apparent crystallite and chromophore sizes in as-prepared aerogels. Higher concentrations of the sol result in larger crystallite
sizes and lower degrees of quantum confinement, as evidenced by a red shift in the absorbance spectra. 相似文献
9.
Gulmini M Appolonia L Framarin P Mirti P 《Analytical and bioanalytical chemistry》2006,386(6):1815-1822
Twelve finds from archaeological excavations carried out in the Aosta region (Italy) were studied by scanning electron microscopy
coupled with energy-dispersive X-ray detection (SEM–EDS). The archaeological samples were shards of glazed pottery dating
from the fourth to the seventh century AD. Analysis of ceramic bodies revealed a general homogeneity in composition among
the studied samples and the use of a noncalcareous clay for their manufacture; however, two shards stand out due to their
high iron contents. Glazes proved to be high-lead products with more than 70% PbO in all of the samples investigated but one.
For the latter, a composition poorer in lead and richer in silicon, aluminium and iron was found. SEM observation of the contact
region between body and glaze suggests that the vitreous coatings were mostly obtained by applying the glazing components
onto the unfired clay body; moreover, a comparison between clay and glaze compositions suggests the use of a lead compound
mixed with a silica-rich material, not a lead compound by itself. 相似文献
10.
Jian Zhu Gary Solbrekken Wentao Hao Yinde Li Jianming Zhen Tongxiu Zhen Michael D. Glascock 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(1):237-242
Neutron activation analysis (NAA) is an important technique to determine the provenance of ancient ceramics. The most common technique used for preparing ancient samples for NAA is to grind them into a powder and then encapsulate them before neutron irradiation. Unfortunately, ceramic materials are typically very hard making it a challenge to grind them into a powder. In this study we utilize bulk porcelain samples cut from ancient shards. The bulk samples are irradiated by neutrons alongside samples that have been conventionally ground into a powder. The NAA for both the bulk samples and powders are compared and shown to provide equivalent information regarding their chemical composition. Also, the multivariate statistical have been employed to the analysis data for check the consistency. The findings suggest that NAA results are less dependent on the state of the porcelain sample, and thus bulk samples cut from shards may be used to effectively determine their provenance. 相似文献
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13.
L. Sabbatini M. G. Tarantino P. G. Zambonin G. E. De Benedetto 《Fresenius' Journal of Analytical Chemistry》2000,366(1):116-124
As a part of a systematic study aimed at assessing the chemical composition of ancient pigments as well as at collecting
information useful for the understanding of the technical aspects related to pottery preservation and decoration, the results
of analysis performed on red, brown and black pigments decorating pre-Roman pottery excavated in thirteen different tombs
unearthed in the archaeological zone of Canosa (Puglia, Italy) are presented. Both surface (XPS) and bulk (FT-IR) spectroscopies
were used which gave complementary information and XRD was used in some cases to further support the spectral assignments.
Results suggested that the shards characterized by “nominally” the same color could be differentiated by the chemical composition
of the pigmented layers; in particular, the shards exhibiting the red pigment could be divided into three groups containing,
respectively, either hematite or ochre plus other substances not related to the color but of great concern for the understanding
of ancient techniques used for color preparation. Manganese oxides were found to be the basis of the brown pigments, which
could be divided into three groups on the basis of Mn and Fe contents. Either magnetite or carbon of vegetable origin was
found in the black-pigmented layers. Furthermore, an attempt was made to find a possible correlation between this classification
and the results of a provenance study carried out on the same pool of shards analyzed in the present investigation.
Received: 28 May 1999 / Revised: 6 August 1999 / Accepted: 21 August 1999 相似文献
14.
L. Sabbatini M. G. Tarantino P. G. Zambonin G. E. De Benedetto 《Analytical and bioanalytical chemistry》2000,366(1):116-124
As a part of a systematic study aimed at assessing the chemical composition of ancient pigments as well as at collecting information useful for the understanding of the technical aspects related to pottery preservation and decoration, the results of analysis performed on red, brown and black pigments decorating pre-Roman pottery excavated in thirteen different tombs unearthed in the archaeological zone of Canosa (Puglia, Italy) are presented. Both surface (XPS) and bulk (FT-IR) spectroscopies were used which gave complementary information and XRD was used in some cases to further support the spectral assignments. Results suggested that the shards characterized by “nominally” the same color could be differentiated by the chemical composition of the pigmented layers; in particular, the shards exhibiting the red pigment could be divided into three groups containing, respectively, either hematite or ochre plus other substances not related to the color but of great concern for the understanding of ancient techniques used for color preparation. Manganese oxides were found to be the basis of the brown pigments, which could be divided into three groups on the basis of Mn and Fe contents. Either magnetite or carbon of vegetable origin was found in the black-pigmented layers. Furthermore, an attempt was made to find a possible correlation between this classification and the results of a provenance study carried out on the same pool of shards analyzed in the present investigation. 相似文献
15.
Substituent Effects on Reduction Potentials of Meta-substituted and Para-substituted Benzylideneanilines
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Effects of meta-substituent of 3,4'/4,3'/3,3'-substituted benzylideneanilines (XBAYs) on the electrochemical reduction potentials (E(Red)) were investigated, in which 49 samples of target compounds were synthesized, and their reduction potentials were measured by cyclic voltammetry. The substituent effects on the E(Red) of target compounds were analyzed and an optimality equation with four parameters (Hammett constant σ of X, Hammett constant σ of Y, excited-state substituent constant σCCex of X, and the substituent specific cross-interaction effect ΔσCCex2 between X and Y) was obtained. The results show that the factors affecting the E(Red) of 3,4'/4,3'/3,3'-substituted XBAYs are different from those of 4,4'-substituted XBAYs. For 3,4'/4,3'/3,3'-substituted XBAYs, σ(X) and σ(Y) must be employed, and the contribution of ΔσCCex2 is important and not negligible. Compared with 4,4'-substituted XBAYs, X group contributes less to 3,4'/4,3'/3,3'-substituted XBAYs, while Y group contributes more to them. Additionally, it was observed that either para-substituted XBAYs or meta-substituted XBAYs, the substituent effects of X are larger than those of Y on the E(Red) of substituted XBAYs. 相似文献
16.
Mathieu Gaudin Maï Panchal Sophie Ayciriex Erwan Werner Alain Brunelle David Touboul Claire Boursier‐Neyret Nicolas Auzeil Bernard Walther Charles Duyckaerts Olivier Laprévote 《Journal of mass spectrometry : JMS》2014,49(10):1035-1042
The development of ‘omics’ sciences offers new opportunities for the study of neurodegenerative diseases but increases at the same time the sample demand on brain banks that collect and store valuable human post‐mortem tissue. Our study aims to evaluate in lipidomics the potential of formalin‐fixed tissue compared with the cryopreservation method, considered as the gold standard for biochemical research. Two complementary liquid chromatography/mass spectrometry analytical platforms were used on the basis of hybrid quadrupole time‐of‐flight and triple quadrupole mass spectrometers. Untargeted fingerprinting, semitargeted profiling of specific lipid classes and targeted monitoring of lipid species were performed in formalin‐fixed and cryopreserved samples to provide detailed information at the molecular level on the formalin‐induced alterations of the brain tissue. In vitro incubations of lipid standards were also performed to further describe the degradation processes induced by formaldehyde. Phospholipid compounds were found to be extensively hydrolysed, whilst the sphingolipid ones were preserved. N‐methylation and N‐formylation of amine‐containing phospholipids have also been evidenced. These findings show that the potential detrimental effect of formalin on the analytes of interest must be taken into account when analysing formalin‐fixed samples. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
17.
Multielement analysis of sixteen Ayyubid–Mamluk glazed pottery sherds was done for determination of chemical composition in order to study their provenance. The sherds tested in the present research come from the historical site of Khirbet Faris on the Karak Plateau in Jordan. The chemical analysis was carried out by inductively coupled plasma mass spectroscopy (ICP-MS). Mg, Al, Ti, V, Cr, Mn, Ni, Cu, Mo, Bi and U have been determined in the studied samples. The data were analyzed by using principal component analysis PCA and hierarchical cluster analysis with Bray-Curtis in order to define grouping of different glazed potteries by obtaining information about their similarity and clustering. The results of chemical analysis provided persuasive evidence that the Khirbet Faris pottery sherds have at least three different sources of provenance. 相似文献
18.
Kuligowski J Carrión D Quintás G Garrigues S de la Guardia M 《Analytical and bioanalytical chemistry》2011,399(3):1305-1314
The selection of an appropriate calibration set is a critical step in multivariate method development. In this work, the effect
of using different calibration sets, based on a previous classification of unknown samples, on the partial least squares (PLS)
regression model performance has been discussed. As an example, attenuated total reflection (ATR) mid-infrared spectra of
deep-fried vegetable oil samples from three botanical origins (olive, sunflower, and corn oil), with increasing polymerized
triacylglyceride (PTG) content induced by a deep-frying process were employed. The use of a one-class-classifier partial least
squares-discriminant analysis (PLS-DA) and a rooted binary directed acyclic graph tree provided accurate oil classification.
Oil samples fried without foodstuff could be classified correctly, independent of their PTG content. However, class separation
of oil samples fried with foodstuff, was less evident. The combined use of double-cross model validation with permutation
testing was used to validate the obtained PLS-DA classification models, confirming the results. To discuss the usefulness
of the selection of an appropriate PLS calibration set, the PTG content was determined by calculating a PLS model based on
the previously selected classes. In comparison to a PLS model calculated using a pooled calibration set containing samples
from all classes, the root mean square error of prediction could be improved significantly using PLS models based on the selected
calibration sets using PLS-DA, ranging between 1.06 and 2.91% (w/w). 相似文献
19.
Thermal and Photolytic Transformation of NHC–B,N‐Heterocycles: Controlled Generation of Blue Fluorescent 1,3‐Azaborinine Derivatives and 1H‐Imidazo[1,2‐a]indoles by External Stimuli
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Sean M. McDonald Soren K. Mellerup Dr. Jinbao Peng Dengtao Yang Prof. Dr. Quan‐Song Li Prof. Dr. Suning Wang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(40):13961-13970
NHC–B,N‐heterocyclic compounds have been found to act as convenient precursors for obtaining either 1,3‐azaborinine or 1H‐imidazo[1,2‐a]indole derivatives, which are two different and rare classes of compounds. The formation of these two classes of compounds from the NHC–B,N‐heterocycles is highly selective depending on the external stimuli employed, and the resulting products have been studied for their interesting chemical and photophysical properties. The mechanism and possible reaction pathways of the unusual transformation are established by computational studies. 相似文献
20.
Kinetics of the reactions of bissulfonyl ethylenes with various carbanions, a sulfur ylide, and siloxyalkenes have been investigated photometrically at 20 °C. The second‐order rate constants have been combined with the known nucleophile‐ specific parameters N and sN for the nucleophiles to calculate the empirical electrophilicity parameters E of bissulfonyl ethylenes according to the linear free energy relationship log k(20 °C)=sN(N+E). Structure‐reactivity relationships are discussed, and it is shown that the electrophilicity parameters E derived in this work can be employed to define the synthetic potential of bissulfonyl ethylenes as Michael acceptors. 相似文献