Identification of conservation and restoration materials for iron relics through ultraviolet-induced visible luminescence imaging and pyrolysis-gas chromatography/mass spectrometry

doi:10.3724/SP.J.1123.2024.02005

Abstract

Abstract:

Understanding the previous protection and restoration efforts and the current state of cultural relics is essential before compiling a conservation and restoration plan. The lack of detailed archival records for some early conservation operations, the identification of restoration materials necessitates the use of scientific analytical methods. In this study, the composition and spatial distribution of historical restoration materials on five iron relics were investigated through pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and ultraviolet-induced visible luminescence imaging (UVL). The relics studied were iron weight 20791, iron adze head 2335, and iron axe 2334 from the Gansu Provincial Museum, iron sword D0008 from the Zhaotong Municipal Museum, and iron sword 450 from the National Museum of China. All five relics had undergone restoration without accompanying archival records. UVL revealed the distribution of various conservation materials. Notably, two distinct layers of the conservation material were observed on iron axe 2334. Differences in the fluorescence color and intensity of iron sword 450 provided information regarding the sampling strategy. The samples were collected under ultraviolet light emitting diode illumination to ensure representativeness and minimize damage to the relics. Through Py-GC/MS, the coating materials for iron weight 20791 and iron adze head 2335 were identified as boiled tung oil mixed with rosin resin. Iron axis 2334 had a two-layer coating: a base layer of boiled tung oil and a top layer of shellac. The coating material for iron sword D0008 was determined to be paraffin wax. The protective layer of iron sword 450 included multiple materials, including shellac, polystyrene, and bisphenol-A-type epoxy resin. This study confirms that UVL combined with Py-GC/MS serves as an effective technique for analyzing historical restoration materials. UVL guided the selection of representative samples for Py-GC/MS, reducing the time and amount of sampling required and minimizing further damage to the relics. This research provides valuable data for the restoration archives of five iron artifacts, offering a scientific basis for conservators to evaluate conservation methods, devise future conservation strategies, and exclude ineffective conservation materials.

Key words: ultraviolet-induced visible luminescence imaging (UVL), pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS), conservation and restoration materials, iron relics

CLC Number:

O658

YANG Qin, DING Li, LI Zhaohui, ZHANG Ran, WEI Yue, CHEN Ying. Identification of conservation and restoration materials for iron relics through ultraviolet-induced visible luminescence imaging and pyrolysis-gas chromatography/mass spectrometry[J]. Chinese Journal of Chromatography, 2024, 42(10): 996-1005.

Figures/Tables 12

References

[1]	Zhao D D, Cheng Q, Guo H. China Cultural Heritage, 2020(4): 83
[1]	赵丹丹, 成倩, 郭宏. 中国文化遗产, 2020(4): 83
[2]	Wang Z, Su B M, Yu Z R, et al. Spectroscopy and Spectral Analysis, 2020, 40(2): 6
[2]	王卓, 苏伯民, 于宗仁, 等. 光谱学与光谱分析, 2020, 40(2): 6
[3]	Zhao J L, Su B M, Yu Z R, et al. Sciences of Conservation and Archaeology, 2022, 34(3): 108
[3]	赵金丽, 苏伯民, 于宗仁, 等. 文物保护与考古科学, 2022, 34(3): 108
[4]	Cavaleri T, Pelosi C, Caliri C, et al. J Cult Herit, 2024, 66: 142
[5]	National Cultural Heritage Administration. Technical Manual for the Protection of Iron Cultural Relics in Museums. Beijing: Cultural Relics Press, 2011
[5]	国家文物局. 博物馆铁质文物保护技术手册. 北京: 文物出版社, 2011
[6]	Shen D W, Ma L Z, Pan L, et al. Paint & Coating Industry, 2009, 39(1): 17
[6]	沈大娲, 马立治, 潘路, 等. 涂料工业, 2009, 39(1): 17
[7]	Bonaduce I, Ribechini E, Modugno F, et al. Top Curr Chem, 2016, 374(1): 6
[8]	Picollo M, Stols-Witlox M, Fuster-López L. UV-Vis Luminescence Imaging Techniques. Editorial Universitat Politècnica de València, 2019. [2024-02-07]. https://doi.org/10.4995/360.2019.110002
[9]	Dyer J, Verri G, Cupitt J. Multispectral Imaging in Reflectance and Photo-induced Luminescence Modes: a User Manual. London: The British Museum, 2013
[10]	Degano I, Modugno F, Bonaduce I, et al. Angew Chem Int Ed Engl, 2018, 57(25): 7313
[11]	Rial-Otero R, Galesio M, Capelo J-L, et al. Chromatographia, 2009, 70(3): 339
[12]	Zhao D K. Cultural Relics, 1981(12): 6
[12]	赵德康. 文物, 1981(12): 6
[13]	Tsakalof A K, Bairachtari K A, Chryssoulakis I D. J Sep Sci, 2006, 29(11): 1642
[14]	He L, Nie M Q, Chiavari G. Journal of Xi’an Jiaotong University, 2006, 40(10): 5
[14]	和玲, 聂麦茜, Chiavari G. 西安交通大学学报, 2006, 40(10): 5
[15]	Wang N, He L, Zhao X, et al. Microchem J, 2015, 123: 201
[16]	Zuber B, Cersoy S, Herbin M, et al. Vib Spectrosc, 2021, 117: 103310
[17]	[Song] Li J. YingZaoFaShi
[17]	[宋] 李诫. 营造法式
[18]	Sutherland K, del Río J C. J Chromatogr A, 2014, 1338(1): 149
[19]	Molina M T, Cano E, Ramírez-Barat B. J Cult Herit, 2023, 62: 99
[20]	Swartz N, Clare T L. J Amer Inst Conserv, 2015, 54(3): 181
[21]	Fabbri D, RomboLà A G, Vassura I, et al. J Anal Appl Pyrol, 2020, 149: 104836

Peak No.	t_R/min	Compound	Match score	Formula	RI-RI(lib)^*
1	8.06	propane, 1,2,3-trimethoxy-	97	C₆H₁₄O₃	-1
2	8.51	hexanoic acid, methyl ester	81	C₇H₁₄O₂	8
3	9.23	2,3-dimethoxypropan-1-ol	95	C₅H₁₂O₃	-40
4	11.01	6-heptenoic acid, methyl ester	98	C₈H₁₄O₂	-37
5	11.17	heptanoic acid, methyl ester	91	C₈H₁₆O₂	6
6	12.17	2-hydroxyisocaproic acid, methyl ether, methyl ester	82	C₈H₁₆O₃	-42
7	13.43	3-octenoic acid, methyl ester, (Z)-	89	C₉H₁₆O₂	-8
8	15.97	8-nonenoic acid, methyl ester	83	C₁₀H₁₈O₂	10
9	18.25	4-decenoic acid, methyl ester	80	C₁₁H₂₀O₂	-18
10	21.10	octanedioic acid, dimethyl ester	98	C₁₀H₁₈O₄	10
11	21.39	dimethyl phthalate	93	C₁₀H₁₀O₄	2
12	23.19	nonanedioic acid, dimethyl ester	99	C₁₁H₂₀O₄	7
13	25.09	decanedioic acid, dimethyl ester	93	C₁₂H₂₂O₄	11
14	26.92	undecanedioic acid, dimethyl ester	88	C₁₃H₂₄O₄	12
15	28.66	dodecanedioic acid, dimethyl ester	80	C₁₄H₂₆O₄	16
16	29.84	hexadecanoic acid, methyl ester	98	C₁₇H₃₄O₂	20
17	32.57	10-octadecenoic acid, methyl ester	92	C₁₉H₃₆O₂	26
18	32.67	9-octadecenoic acid, methyl ester, (E)-	93	C₁₉H₃₆O₂	25
19	32.99	methyl stearate	95	C₁₉H₃₈O₂	22
20	33.33	nonanoic acid, 9-(o-propylphenyl)-, methyl ester	82	C₁₉H₃₀O₂	39
21	34.77	sandaracopimaric acid methyl ester	80	C₂₁H₃₂O₂	25
22	35.86	methyl 18-methylnonadecanoate	85	C₂₁H₄₂O₂	-12
23	36.22	methyl dehydroabietate	92	C₂₁H₃₀O₂	7
24	37.76	tetradehydroabietic acid, 7-methoxy-, methyl ester	87	C₂₂H₃₀O₃	-25
25	39.62	7,15-dimethoxytetradehydroabietic acid, methyl ester	80	C₂₃H₃₂O₄	-15

Peak No.	t_R/min	Compound	Match score	Formula	RI-RI(lib)^*
1	8.06	propane, 1,2,3-trimethoxy-	97	C₆H₁₄O₃	-1
2	8.51	hexanoic acid, methyl ester	81	C₇H₁₄O₂	8
3	9.23	2,3-dimethoxypropan-1-ol	95	C₅H₁₂O₃	-40
4	11.01	6-heptenoic acid, methyl ester	98	C₈H₁₄O₂	-37
5	11.17	heptanoic acid, methyl ester	91	C₈H₁₆O₂	6
6	12.17	2-hydroxyisocaproic acid, methyl ether, methyl ester	82	C₈H₁₆O₃	-42
7	13.43	3-octenoic acid, methyl ester, (Z)-	89	C₉H₁₆O₂	-8
8	15.97	8-nonenoic acid, methyl ester	83	C₁₀H₁₈O₂	10
9	18.25	4-decenoic acid, methyl ester	80	C₁₁H₂₀O₂	-18
10	21.10	octanedioic acid, dimethyl ester	98	C₁₀H₁₈O₄	10
11	21.39	dimethyl phthalate	93	C₁₀H₁₀O₄	2
12	23.19	nonanedioic acid, dimethyl ester	99	C₁₁H₂₀O₄	7
13	25.09	decanedioic acid, dimethyl ester	93	C₁₂H₂₂O₄	11
14	26.92	undecanedioic acid, dimethyl ester	88	C₁₃H₂₄O₄	12
15	28.66	dodecanedioic acid, dimethyl ester	80	C₁₄H₂₆O₄	16
16	29.84	hexadecanoic acid, methyl ester	98	C₁₇H₃₄O₂	20
17	32.57	10-octadecenoic acid, methyl ester	92	C₁₉H₃₆O₂	26
18	32.67	9-octadecenoic acid, methyl ester, (E)-	93	C₁₉H₃₆O₂	25
19	32.99	methyl stearate	95	C₁₉H₃₈O₂	22
20	33.33	nonanoic acid, 9-(o-propylphenyl)-, methyl ester	82	C₁₉H₃₀O₂	39
21	34.77	sandaracopimaric acid methyl ester	80	C₂₁H₃₂O₂	25
22	35.86	methyl 18-methylnonadecanoate	85	C₂₁H₄₂O₂	-12
23	36.22	methyl dehydroabietate	92	C₂₁H₃₀O₂	7
24	37.76	tetradehydroabietic acid, 7-methoxy-, methyl ester	87	C₂₂H₃₀O₃	-25
25	39.62	7,15-dimethoxytetradehydroabietic acid, methyl ester	80	C₂₃H₃₂O₄	-15

Peak No.	t_R/min	Compound	Match score	Formula	RI-RI(lib)
1	4.48	toluene	88	C₇H₈	11
2	8.23	propane, 1,2,3-trimethoxy-	81	C₆H₁₄O₃	-8
3	8.34	5-hexenoic acid, methyl ester	88	C₇H₁₂O₂	-36
4	11.03	6-heptenoic acid, methyl ester	97	C₈H₁₄O₂	-37
5	13.47	3-octenoic acid, methyl ester, (Z)-	81	C₉H₁₆O₂	-10
6	20.20	longifolene	94	C₁₅H₂₄	9
7	21.11	octanedioic acid, dimethyl ester	96	C₁₀H₁₈O₄	9
8	21.39	dimethyl phthalate	96	C₁₀H₁₀O₄	2
9	23.14	nonanedioic acid, dimethyl ester	94	C₁₁H₂₀O₄	10
10	26.08	methyl myristoleate	92	C₁₅H₂₈O₂	25
11	26.38	methyl tetradecanoate	94	C₁₅H₃₀O₂	18
12	28.80	butolic acid, methyl ester, methyl ether	95	C₁₆H₃₂O₃	13
13	29.56	9-hexadecenoic acid, methyl ester, (Z)-	95	C₁₇H₃₂O₂	9
14	29.85	hexadecanoic acid, methyl ester	97	C₁₇H₃₄O₂	19
15	32.69	11-octadecenoic acid, methyl ester	82	C₁₉H₃₆O₂	29
16	32.84	laccishellolic acid, dimethyl ester, methyl ether	97	C₁₈H₂₆O₅	18
17	32.97	methyl stearate	95	C₁₉H₃₈O₂	23
18	34.85	shellolic acid, dimethyl ester, dimethyl ether	95	C₁₉H₂₈O₆	14
19	36.26	methyl dehydroabietate	94	C₂₁H₃₀O₂	3
20	36.85	aleuritic acid, methyl ester, trimethyl ether	95	C₂₀H₄₀O₅	5
21	37.78	tetradehydroabietic acid, 7-methoxy-, methyl ester	83	C₂₂H₃₀O₃	-26
22	44.44	1-methoxyoctacosane	96	C₂₉H₆₀O	28
23	46.52	methyl triacontyl ether	94	C₃₁H₆₄O	37
24	48.48	dotriacontyl methyl ether	93	C₃₃H₆₈O	37
25	50.52	methyl tetratriacontyl ether	84	C₃₅H₇₂O	41

Peak No.	t_R/min	Compound	Match score	Formula	RI-RI(lib)
1	4.48	toluene	88	C₇H₈	11
2	8.23	propane, 1,2,3-trimethoxy-	81	C₆H₁₄O₃	-8
3	8.34	5-hexenoic acid, methyl ester	88	C₇H₁₂O₂	-36
4	11.03	6-heptenoic acid, methyl ester	97	C₈H₁₄O₂	-37
5	13.47	3-octenoic acid, methyl ester, (Z)-	81	C₉H₁₆O₂	-10
6	20.20	longifolene	94	C₁₅H₂₄	9
7	21.11	octanedioic acid, dimethyl ester	96	C₁₀H₁₈O₄	9
8	21.39	dimethyl phthalate	96	C₁₀H₁₀O₄	2
9	23.14	nonanedioic acid, dimethyl ester	94	C₁₁H₂₀O₄	10
10	26.08	methyl myristoleate	92	C₁₅H₂₈O₂	25
11	26.38	methyl tetradecanoate	94	C₁₅H₃₀O₂	18
12	28.80	butolic acid, methyl ester, methyl ether	95	C₁₆H₃₂O₃	13
13	29.56	9-hexadecenoic acid, methyl ester, (Z)-	95	C₁₇H₃₂O₂	9
14	29.85	hexadecanoic acid, methyl ester	97	C₁₇H₃₄O₂	19
15	32.69	11-octadecenoic acid, methyl ester	82	C₁₉H₃₆O₂	29
16	32.84	laccishellolic acid, dimethyl ester, methyl ether	97	C₁₈H₂₆O₅	18
17	32.97	methyl stearate	95	C₁₉H₃₈O₂	23
18	34.85	shellolic acid, dimethyl ester, dimethyl ether	95	C₁₉H₂₈O₆	14
19	36.26	methyl dehydroabietate	94	C₂₁H₃₀O₂	3
20	36.85	aleuritic acid, methyl ester, trimethyl ether	95	C₂₀H₄₀O₅	5
21	37.78	tetradehydroabietic acid, 7-methoxy-, methyl ester	83	C₂₂H₃₀O₃	-26
22	44.44	1-methoxyoctacosane	96	C₂₉H₆₀O	28
23	46.52	methyl triacontyl ether	94	C₃₁H₆₄O	37
24	48.48	dotriacontyl methyl ether	93	C₃₃H₆₈O	37
25	50.52	methyl tetratriacontyl ether	84	C₃₅H₇₂O	41