Journal of Molecular Structure 924–926 (2009) 400–403

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Journal of Molecular Structure

journal homepage: www.elsevier .com/locate /molstruc

FT-IR and EDXRF analysis of wall paintings of ancient Ainos Hagia Sophia Church

S. Akyuz a,*, T. Akyuz a, S. Basaran b, I. Kocabas b, A. Gulec b, H. Cesmeli b, B. Ucar b

a Istanbul Kultur University, Science and Letters Faculty, Physics Department, Atakoy Campus, 34156 Bakirkoy, Istanbul, Turkeyb Istanbul University, Letters Faculty, Department of Restoration and Conservation of Artefacts, Vezneciler, 34134 Istanbul, Turkey

a r t i c l e i n f o

Article history:Received 30 October 2008Accepted 12 January 2009Available online 20 January 2009

Keywords:Ancient wall paintingsArchaeometryEDXRFInorganic pigmentsIR spectroscopy

0022-2860/$ - see front matter � 2009 Elsevier B.V. Adoi:10.1016/j.molstruc.2009.01.020

* Corresponding author. Tel.: +90 212 661 9274; faE-mail address: s.akyuz@iku.edu.tr (S. Akyuz).

a b s t r a c t

The wall paintings of ancient Ainos Hagia (Saint) Sophia Church were investigated by FT-IR and EDXRFspectroscopy. Calcite, aragonite, gypsum, and quartz were detected in all the samples. Feldspar phasesand pigments were inferred from both band component analysis and the second derivative profiles ofthe IR spectra. The black, dark brown, and red colouration was due to different concentrations ofMnO2, Mn2O3, magnetite, and haematite.

� 2009 Elsevier B.V. All rights reserved.

1. Introduction

IR spectroscopy has been widely used recently as an analyticaltechnique for investigations of historical and cultural artefacts[1–4]. The identification of pigments used for archaeological arte-facts is important for their restoration, conservation, dating, andauthentication [5–7]. In ancient times, paintings were a veryimportant educational tool used to give messages to the people.This is the reason why there are numerous examples of muralpaintings particularly on the walls of ancient churches.

Ancient Ainos (Enez, Turkey) was founded on the northern coastof the Aegean Sea, and it is one of the most important archaeolog-ical sites in Turkey. Hagia, i.e., Saint, Sophia Church of ancient Ai-nos dates back to the Byzantine age (12th century). The aim ofthis study is to investigate the chemical composition of pigmentsand typical mortars used in the ancient mural paintings of HagiaSophia Church (Enez, Turkey), using FT-IR and EDXRF spectrome-try. A photograph of ancient Ainos Hagia Sophia Church is givenin Fig. 1, and detailed photographs of the wall paintings studiedare given in Fig. 2.

2. Experimental

IR spectra of the KBr discs of the samples were collected using aJasco-300 FT-IR spectrometer. The spectra are the average of 150measurements. Spectral manipulation, such as baseline adjust-ment, smoothing, and second derivative calculations, were per-

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formed using the GRAMS/AI 7.02 (Thermo Electron Corporation)software package. EDXRF spectra of the samples were recordedon a spectro IQ XIQ01 model spectrometer.

3. Results and discussion

The FT-IR spectra of grey, light blue-grey, red, and brown pig-mented layers of the wall paintings are given in Fig. 3. All exam-ined samples showed the presence of calcium in highconcentrations. Band component analyses in comparison with sec-ond derivative profiles of the IR spectra of the investigated sampleswere found to be very useful for the identification of overlappingbands. Fig. 4 shows the band component analysis of the carbonatestretching region of the pink coloured sample, in comparison tothat of its second derivative profile. The 1488 m and 1451 s cm�1

bands can be attributed to aragonite and the 1418 cm�1 strongband to calcite phases of calcium carbonate [8]. The spectrum alsoreveals the presence of ammonium carbonate (1393 cm�1), whichprobably arises owing to environmental effects. In addition to thecarbonate stretching region, the other bands of the calcite and ara-gonite phases are shown in the IR spectrum of the pink pigmentedpart of the wall painting (see Fig. 5); 2512, 1796, 712 cm�1 (cal-cite–aragonite) and 1447 cm�1 (aragonite) and 1434 cm�1 (calcite)phases.

The band component analysis in comparison to the secondderivative profile of the 1260–900 cm�1 region of the IR absorptionspectrum of the pink coloured part of the wall painting is given inFig. 6. The presence of gypsum (1164, 1144, 1116, 1006 cm�1),quartz (1164, 1086 and 913 cm�1) microcline (1142, 1054 cm�1),illite (1031 cm�1), and chlorite (986 cm�1) were inferred [1,8].

Fig. 4. Band component analysis and the second derivative of the 1750–1250 cm�1

region of the IR absorption spectrum of the pink coloured part of the wall painting.A = aragonite; C = calcite; am = ammonium carbonate bands. (For interpretation ofthe references to colour in this figure legend, the reader is referred to the webversion of this article.)

Fig. 5. The FT-IR spectrum of the pink coloured part of the wall painting. (Forinterpretation of the references to colour in this figure legend, the reader is referredto the web version of this article.)

Fig. 2. Wall paintings (a and b) and inner place (c) of ancient Ainos Hagia SophiaChurch.

Fig. 1. Ancient Ainos Hagia Sophia Church.

Fig. 3. The FT-IR spectra of grey (a), red (b), light blue-grey (c), and brown (d)coloured parts of the wall paintings. (For interpretation of the references to colourin this figure legend, the reader is referred to the web version of this article.)

S. Akyuz et al. / Journal of Molecular Structure 924–926 (2009) 400–403 401

Fig. 6. Band component analysis and the second derivative of the 1260–900 cm�1

region of the IR absorption spectrum of the pink coloured part of the wall painting.C = calcite; CH = chlorite; G = gypsum; I = illite; M = microline; Q = quartz bands.(For interpretation of the references to colour in this figure legend, the reader isreferred to the web version of this article.)

Fig. 8. 810–650 cm�1 region of the IR absorption spectrum of the dark greycoloured part of the wall painting. Band component analysis results and the secondderivative profile are also given. (For interpretation of the references to colour inthis figure legend, the reader is referred to the web version of this article.)

402 S. Akyuz et al. / Journal of Molecular Structure 924–926 (2009) 400–403

The detailed IR spectrum of the same region of the grey colouredpart of the wall painting is given in Fig. 7. Chlorite (987 cm�1), gyp-sum (1165, 1142, 1114, 1005 cm�1), illite (1030, 908 cm�1), micro-cline (1142, 1055 cm�1), and quartz (1165, 1079 cm�1) bands wereidentified. The 810–650 cm�1 region of the IR spectrum of the darkgrey part of the wall painting is given in Fig. 8. From this spectrum,quartz (797, 778, 778 and 692 cm�1), chlorite (758 cm�1), micro-cline (742, 670 cm�1), and spinel {8[MgAl2O4], 685 cm�1} [9–12]bands were observed. The 733 cm�1 w band can be attributed toMnO2. Fig. 9 represents the 700–400 cm�1 region of the FT-IR spec-trum of the dark grey coloured part of the wall painting in compar-ison with its second derivative profile. The presence of albite (648,422 cm�1), chlorite (557, 456, 447 cm�1), gypsum (602 cm�1), hae-matite (574, 532, 475 cm�1), magnetite (670 cm�1), microline (644,582, 537, 462, 427 cm�1), Mn2O3 (635 cm�1), and MnO2 (670, 590,432 cm�1) were inferred.

Fig. 7. Band component analysis and the second derivative of the 1200–905 cm�1

region of the IR absorption spectrum of the grey coloured part of the wall painting.CH = chlorite (987 cm�1); G = gypsum (1165, 1142, 1114, 1005 cm�1); I = illite(1030, 908 cm�1); M = microline (1142, 1055 cm�1); Q = quartz (1165, 1079 cm�1).(For interpretation of the references to colour in this figure legend, the reader isreferred to the web version of this article.)

Fig. 9. 700–400 cm�1 region of the FT-IR spectrum and its second derivative profileof the dark grey coloured part of the wall painting. A = albite (648, 422 cm�1);Ch = chlorite (557, 456, 447 cm�1); G = gypsum (602 cm�1); H = haematite (574,532, 475 cm�1); M = magnetite (670 cm�1); Mic = microline (644, 582, 537, 462,427 cm�1); Mn-III = Mn2O3 (635 cm�1); Mn-IV = MnO2 (590, 432 cm�1). (For inter-pretation of the references to colour in this figure legend, the reader is referred tothe web version of this article.)

The EDXRF results revealed the presence of abundant calcium(80–30%) in the investigated samples, and the amount of calciumincreased in the inner parts. In addition to calcium, differentamounts of magnesium, iron, sulfur, aluminum, potassium, silicon,chlorine and manganese were detected. The XRF findings are com-patible with those of the IR spectroscopic results.

4. Conclusions

Application of IR spectroscopy together with XRF to the analysisof ancient wall paintings enabled us to determine the analyticalcomposition of the pigments and mortar used in the wall paintingsof ancient Ainos Hagia (Saint) Sophia Church dating back to theByzantine age (12th century). Calcite, aragonite, gypsum, andquartz were detected in all the samples. Feldspar phases and pig-ments were inferred from both band component analysis and the

S. Akyuz et al. / Journal of Molecular Structure 924–926 (2009) 400–403 403

second derivative profiles of the IR spectra. The black, dark brownand red colouration was due to different concentrations of MnO2,Mn2O3, magnetite, and haematite.

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