Jana Hrncirova, Marguerite R. Butler, Meredith R. Clark, Gustavo F. Doncel, John B. Cooper
In this study, an antiretroviral drug emtricitabine (also known as FTC or Emtriva) was detected and quantified down to 40 ng/ml by using surface‐enhanced Raman spectroscopy (SERS). Its aqueous standards were tested with two types of silver nanoparticles (colloidal and dendritic) using a specially developed aluminum well plate. The SERS spectra were acquired using a Raman scanning device with 30‐μm spatial resolution. The spectral data were analyzed using a new approach for the discrimination of the spatially acquired spectra based on the Quality index (Qi). After the Qi is calculated, the spectral data are sorted based on the Qi. This is followed by selecting only the spectra with a high Qi index and comparing the average of all the spatially acquired spectra. This results in an improvement in the spectral signal‐to‐noise and higher analytical sensitivity of the built calibration curves.
{"title":"A new approach for discriminating spatially acquired SERS spectra using antiretroviral drug emtricitabine as a test sample","authors":"Jana Hrncirova, Marguerite R. Butler, Meredith R. Clark, Gustavo F. Doncel, John B. Cooper","doi":"10.1002/jrs.6721","DOIUrl":"https://doi.org/10.1002/jrs.6721","url":null,"abstract":"In this study, an antiretroviral drug emtricitabine (also known as FTC or Emtriva) was detected and quantified down to 40 ng/ml by using surface‐enhanced Raman spectroscopy (SERS). Its aqueous standards were tested with two types of silver nanoparticles (colloidal and dendritic) using a specially developed aluminum well plate. The SERS spectra were acquired using a Raman scanning device with 30‐μm spatial resolution. The spectral data were analyzed using a new approach for the discrimination of the spatially acquired spectra based on the Quality index (Qi). After the Qi is calculated, the spectral data are sorted based on the Qi. This is followed by selecting only the spectra with a high Qi index and comparing the average of all the spatially acquired spectra. This results in an improvement in the spectral signal‐to‐noise and higher analytical sensitivity of the built calibration curves.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Minli Wang, Christophe Faulmann, Fen Wang, Tian Wang, Philippe Sciau
Black and white porcelain plays a critical role in Chinese decorative porcelain history. It is famous for its decorative styles and techniques, which create a strong black and white color contrast in its appearance. In this study, representative black and white porcelains produced in Shanxi province were analyzed by X‐ray fluorescence, Raman spectroscopy, and SEM‐EDS. The results show that both Ca‐rich (~5.33 wt%) and Ca‐poor (~1.99 wt%) glazes were used leading to quite different microstructures. The pigment particles of Ca‐rich glazes are characterized by small size (≤2 μm), wide distribution, and tightly wrapped by anorthite. In contrast, they are larger (≥2 μm) and tightly cumulated together in Ca‐poor glazes. Hematite is the major crystal in pigment, double‐substituted by Al and Ti. The Al/Fe ratios are similar, but Ti/Fe ratios are quite different: They do not exceed 0.03% in Ca‐poor glazes, whereas they reach 0.12% in Ca‐rich glazes, suggesting that the origin of the pigments must be different. Al‐rich mineral such as kaolin was added to the pigment preparation in Ca‐rich glazes. The color of the pattern is mainly influenced by the size, quantity, and concentration of brown Ti‐doping hematite, as well as the thickness of the glaze layer and other crystals and Fe ions. The fired atmosphere of Ca‐rich glaze type seems less oxidizing than for Ca‐poor glaze type. Overall, the results confirm that black and white porcelain has a variety of production techniques, which is attributed to the craftsman adjusting the techniques according to the composition of raw materials.
黑白瓷器在中国瓷器装饰史上占有举足轻重的地位。它以其装饰风格和技法而闻名，在外观上形成了强烈的黑白色彩对比。本研究采用 X 射线荧光、拉曼光谱和扫描电镜-电子显微镜分析了山西省生产的具有代表性的黑白瓷器。结果表明，富钙釉（~5.33 wt%）和贫钙釉（~1.99 wt%）的使用导致了截然不同的微观结构。富钙质釉料的颜料颗粒具有尺寸小（≤2 μm）、分布广、被阳起石紧紧包裹的特点。相反，在贫钙质釉料中，它们的尺寸较大（≥2 μm），并紧密地堆积在一起。赤铁矿是颜料中的主要晶体，由 Al 和 Ti 双取代。铝/铁比率相似，但钛/铁比率却大不相同：在贫钙釉中不超过 0.03%，而在富钙釉中却达到 0.12%，这表明颜料的来源肯定不同。在富钙釉的颜料制备中加入了高岭土等富铝矿物。花纹的颜色主要受棕色掺钛赤铁矿的大小、数量和浓度，以及釉层厚度和其他晶体及铁离子的影响。与贫钙釉相比，富钙质釉的烧成气氛似乎氧化性较低。总之，研究结果证实，黑白瓷器的制作工艺多种多样，这归因于工匠根据原料成分调整工艺。
{"title":"Microscopic study on characteristic decorative black and white porcelain produced in Shanxi province, Jin and Yuan dynasties (ad 1115–1368), China","authors":"Minli Wang, Christophe Faulmann, Fen Wang, Tian Wang, Philippe Sciau","doi":"10.1002/jrs.6722","DOIUrl":"https://doi.org/10.1002/jrs.6722","url":null,"abstract":"Black and white porcelain plays a critical role in Chinese decorative porcelain history. It is famous for its decorative styles and techniques, which create a strong black and white color contrast in its appearance. In this study, representative black and white porcelains produced in Shanxi province were analyzed by X‐ray fluorescence, Raman spectroscopy, and SEM‐EDS. The results show that both Ca‐rich (~5.33 wt%) and Ca‐poor (~1.99 wt%) glazes were used leading to quite different microstructures. The pigment particles of Ca‐rich glazes are characterized by small size (≤2 μm), wide distribution, and tightly wrapped by anorthite. In contrast, they are larger (≥2 μm) and tightly cumulated together in Ca‐poor glazes. Hematite is the major crystal in pigment, double‐substituted by Al and Ti. The Al/Fe ratios are similar, but Ti/Fe ratios are quite different: They do not exceed 0.03% in Ca‐poor glazes, whereas they reach 0.12% in Ca‐rich glazes, suggesting that the origin of the pigments must be different. Al‐rich mineral such as kaolin was added to the pigment preparation in Ca‐rich glazes. The color of the pattern is mainly influenced by the size, quantity, and concentration of brown Ti‐doping hematite, as well as the thickness of the glaze layer and other crystals and Fe ions. The fired atmosphere of Ca‐rich glaze type seems less oxidizing than for Ca‐poor glaze type. Overall, the results confirm that black and white porcelain has a variety of production techniques, which is attributed to the craftsman adjusting the techniques according to the composition of raw materials.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141870031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Macro‐Raman mapping is an approach that allows to obtain high‐resolution molecular maps of artefacts, over an area of several square centimetres. The method is based on recording thousands of spectra in a grid. The main drawback of this method is that it is very time consuming. A straightforward approach to reduce the measurement time is achieved by reducing the number of points that are measured. Not all points of the map are equally informative: Pixels that are surrounded by similar points might be less interesting to measure. Therefore, an algorithm is proposed to select where to measure and which points to omit. The missing pixels can be filled in a posteriori, by using a suitable interpolation algorithm. The selection of the omitted pixels can be performed based on information that is available from other analytical techniques. In this case, a selection was made based on the local variances in a colour picture. The approach is evaluated by recording macro‐Raman maps of details of a Neptune watercolour painting on paper. In a first stage, the Raman intensities of the scaled and baseline corrected spectra at specific band positions were colour coded and plotted as Raman maps. The interpolation of the Raman maps yielded satisfying results. The image outline could clearly be identified in the maps, and the differently coloured zones were distinguished. Next to this univariate approach, it was demonstrated that also a multivariate data extraction method (principal component analysis) is compatible with the proposed algorithm to measure 25% less datapoints.
{"title":"Speeding up macro‐Raman mapping by reducing the number of sampling points","authors":"Peter Vandenabeele","doi":"10.1002/jrs.6720","DOIUrl":"https://doi.org/10.1002/jrs.6720","url":null,"abstract":"Macro‐Raman mapping is an approach that allows to obtain high‐resolution molecular maps of artefacts, over an area of several square centimetres. The method is based on recording thousands of spectra in a grid. The main drawback of this method is that it is very time consuming. A straightforward approach to reduce the measurement time is achieved by reducing the number of points that are measured. Not all points of the map are equally informative: Pixels that are surrounded by similar points might be less interesting to measure. Therefore, an algorithm is proposed to select where to measure and which points to omit. The missing pixels can be filled in a posteriori, by using a suitable interpolation algorithm. The selection of the omitted pixels can be performed based on information that is available from other analytical techniques. In this case, a selection was made based on the local variances in a colour picture. The approach is evaluated by recording macro‐Raman maps of details of a Neptune watercolour painting on paper. In a first stage, the Raman intensities of the scaled and baseline corrected spectra at specific band positions were colour coded and plotted as Raman maps. The interpolation of the Raman maps yielded satisfying results. The image outline could clearly be identified in the maps, and the differently coloured zones were distinguished. Next to this univariate approach, it was demonstrated that also a multivariate data extraction method (principal component analysis) is compatible with the proposed algorithm to measure 25% less datapoints.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. Rubira, L. N. Furini, M. E. Tuttolomondo, Carlos J. L. Constantino, Santiago Sanchez-Cortes
The excessive use of pesticides has detrimental effects on the ecosystem, leading to soil contamination and the spread of pollution beyond the targeted areas. Concerns arise regarding the permissible limits of pesticides, typically around 10−8 mol/L. In this study, we employed surface‐enhanced Raman spectroscopy (SERS), a highly sensitive and selective technique, to investigate the behavior of the pesticide ametrine (AMT) on silver colloids. The Ag nanoparticles (AgNPs) exhibited an average size of (26 ± 2) nm and a zeta potential of (−30 ± 1) mV in the absence of AMT, which decreased to (−24 ± 1) mV in the presence of AMT, resulting in mild AgNPs aggregation, with the average diameter of AgNPs increasing to approximately 300 nm. This aggregation is advantageous, as they provide active sites for pesticide detection. Besides, the purification method employed ensured that AMT remained undegraded, and various conformations of AMT were simulated using Ag clusters to study the SERS effect. Comparison with the experimental spectra indicated that the SERS‐4 conformer closely resembled the experimental spectrum, suggesting simultaneous interaction between the Ag surface and the sulfur (S) and nitrogen (N) atoms of the AMT triazine ring. Notably, changes in the AMT molecule were observed with pH variations: at pH below 5, hydroxylation occurred, resulting in an Ag–Cl stretching at 241 cm−1 in the SERS spectra. Conversely, at pH above 5 (pH 6–13), the presence of bands at 230 and 219 cm−1 in the SERS spectra indicate the formation of Ag–N and Ag–S bonds, respectively, between the AMT and the AgNPs. Furthermore, the study successfully detected AMT at pH 7, establishing a limit of detection (LOD) of 1.36 × 10−8 mol/L (3 ppb) based on the SERS spectra. These findings underscore the applicability of the SERS technique in the sensitive and selective detection of AMT, offering a promising approach for monitoring the presence of this pesticide in environmental samples.
{"title":"Advancing on ametrine pesticide detection through surface‐enhanced Raman spectroscopy and Ag colloid: Understanding the pH effect and the adsorption mechanism supported by theoretical calculation","authors":"R. Rubira, L. N. Furini, M. E. Tuttolomondo, Carlos J. L. Constantino, Santiago Sanchez-Cortes","doi":"10.1002/jrs.6719","DOIUrl":"https://doi.org/10.1002/jrs.6719","url":null,"abstract":"The excessive use of pesticides has detrimental effects on the ecosystem, leading to soil contamination and the spread of pollution beyond the targeted areas. Concerns arise regarding the permissible limits of pesticides, typically around 10−8 mol/L. In this study, we employed surface‐enhanced Raman spectroscopy (SERS), a highly sensitive and selective technique, to investigate the behavior of the pesticide ametrine (AMT) on silver colloids. The Ag nanoparticles (AgNPs) exhibited an average size of (26 ± 2) nm and a zeta potential of (−30 ± 1) mV in the absence of AMT, which decreased to (−24 ± 1) mV in the presence of AMT, resulting in mild AgNPs aggregation, with the average diameter of AgNPs increasing to approximately 300 nm. This aggregation is advantageous, as they provide active sites for pesticide detection. Besides, the purification method employed ensured that AMT remained undegraded, and various conformations of AMT were simulated using Ag clusters to study the SERS effect. Comparison with the experimental spectra indicated that the SERS‐4 conformer closely resembled the experimental spectrum, suggesting simultaneous interaction between the Ag surface and the sulfur (S) and nitrogen (N) atoms of the AMT triazine ring. Notably, changes in the AMT molecule were observed with pH variations: at pH below 5, hydroxylation occurred, resulting in an Ag–Cl stretching at 241 cm−1 in the SERS spectra. Conversely, at pH above 5 (pH 6–13), the presence of bands at 230 and 219 cm−1 in the SERS spectra indicate the formation of Ag–N and Ag–S bonds, respectively, between the AMT and the AgNPs. Furthermore, the study successfully detected AMT at pH 7, establishing a limit of detection (LOD) of 1.36 × 10−8 mol/L (3 ppb) based on the SERS spectra. These findings underscore the applicability of the SERS technique in the sensitive and selective detection of AMT, offering a promising approach for monitoring the presence of this pesticide in environmental samples.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141644586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sara Valadas, Peter Vandenabeele, Milene Gil, José C. Frade, Eva Vermeersch, Sylvia Lycke, Luís Dias, António Candeias, Mafalda Costa
In 1949, Almada Negreiros painted at the maritime station of Rocha do Conde de Óbidos, in Lisbon, six monumental mural paintings, which are considered as his highest artistic achievement. On these paintings, he resorted to a bright colourful palette, which needs to be studied to support conservation and preservation of these artworks for future generations. Among the pigments under study within project ALMADA, the identification of the green samples is the most challenging, as Almada Negreiros seems to have explored different hues by using simultaneously inorganic (e.g., emerald green, Scheele's green and viridian) as well as organo‐synthetic pigments that were rather unusual when employing a traditional mural painting technique (e.g., PG7 and PG8). Moreover, he seems to have admixed white (e.g., titanium white) or blue pigments (e.g., ultramarine) to modify the hues. The different colourants found, as well as the use of mixtures of pigments, hints that Almada Negreiros was keen on experimenting and applying relatively novel painting materials. Raman spectroscopy, given its ability to identify inorganic as well as organic components, is a key analytical tool to discriminate between all these compounds. The findings were also supported by complimentary analytical techniques, including colourimetry, handheld X‐ray fluorescence spectroscopy (h‐XRF) and micro‐Fourier‐transform infrared spectroscopy (μ‐FT‐IR). Identification of the green pigments by Raman spectroscopy is, however, not always straightforward, and it is demonstrated how changes in relative band intensities and band broadening can point to mixtures, where the Raman spectral features of some compounds can easily be overseen in the spectrum.
1949 年，阿尔马达-内格雷罗斯在里斯本的 Rocha do Conde de Óbidos 海洋站绘制了六幅不朽的壁画，这被认为是他的最高艺术成就。在这些画作中，他使用了色彩鲜艳的调色板，需要对其进行研究，以便为后代保护和保存这些艺术品提供支持。在 ALMADA 项目所研究的颜料中，绿色样本的鉴定最具挑战性，因为 Almada Negreiros 似乎同时使用了无机颜料（如祖母绿、谢尔绿和病毒绿）和有机合成颜料来探索不同的色调，而这些颜料在使用传统壁画技术时是相当少见的（如 PG7 和 PG8）。此外，他似乎还掺入了白色（如钛白）或蓝色颜料（如群青）来改变色调。发现的不同着色剂以及颜料混合物的使用，表明阿尔马达-内格雷罗斯热衷于试验和应用相对新颖的绘画材料。拉曼光谱能够识别无机和有机成分，是区分所有这些化合物的关键分析工具。色度法、手持式 X 射线荧光光谱仪 (h-XRF) 和微傅立叶变换红外光谱仪 (μ-FT-IR)等辅助分析技术也为研究结果提供了支持。然而，通过拉曼光谱鉴别绿色颜料并不总是那么简单，研究表明，相对波段强度和波段展宽的变化可以指向混合物，在混合物中，某些化合物的拉曼光谱特征很容易在光谱中被发现。
{"title":"Analysis of green pigments: The case of Almada Negreiros maritime station murals in Lisbon (Portugal)","authors":"Sara Valadas, Peter Vandenabeele, Milene Gil, José C. Frade, Eva Vermeersch, Sylvia Lycke, Luís Dias, António Candeias, Mafalda Costa","doi":"10.1002/jrs.6717","DOIUrl":"https://doi.org/10.1002/jrs.6717","url":null,"abstract":"In 1949, Almada Negreiros painted at the maritime station of Rocha do Conde de Óbidos, in Lisbon, six monumental mural paintings, which are considered as his highest artistic achievement. On these paintings, he resorted to a bright colourful palette, which needs to be studied to support conservation and preservation of these artworks for future generations. Among the pigments under study within project ALMADA, the identification of the green samples is the most challenging, as Almada Negreiros seems to have explored different hues by using simultaneously inorganic (e.g., emerald green, Scheele's green and viridian) as well as organo‐synthetic pigments that were rather unusual when employing a traditional mural painting technique (e.g., PG7 and PG8). Moreover, he seems to have admixed white (e.g., titanium white) or blue pigments (e.g., ultramarine) to modify the hues. The different colourants found, as well as the use of mixtures of pigments, hints that Almada Negreiros was keen on experimenting and applying relatively novel painting materials. Raman spectroscopy, given its ability to identify inorganic as well as organic components, is a key analytical tool to discriminate between all these compounds. The findings were also supported by complimentary analytical techniques, including colourimetry, handheld X‐ray fluorescence spectroscopy (h‐XRF) and micro‐Fourier‐transform infrared spectroscopy (μ‐FT‐IR). Identification of the green pigments by Raman spectroscopy is, however, not always straightforward, and it is demonstrated how changes in relative band intensities and band broadening can point to mixtures, where the Raman spectral features of some compounds can easily be overseen in the spectrum.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141577761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antonella Privitera, Simone Bernardini, Giancarlo Della Ventura, Paolo Ballirano, Elena Arbolino, Caterina Coletti, Lorenzo Conte, Francesco Pacetti, Simona Morretta, Armida Sodo
A multi‐analytical approach based on colourimetry, micro‐Raman spectroscopy, scanning electron microscopy, optical microscopy and powder X‐ray diffraction, has been applied to investigate Roman cooking ware samples dating back to imperial age (I‐II century AD). In particular, the highly distinctive production of pots coming from two different archaeological sites, ‘Villa della Piscina’ at Centocelle district and the so called ‘Minerva Medica Temple’ at Esquilino district (Rome, Italy), was studied characterising the colour, the chemical, mineralogical and petrographic distinctive properties of the investigated samples, in order to compare technological and provenance aspects. Classification of ceramic fragment by colorimetry, integrated by compositional studies with a main contribution of micro‐Raman spectroscopy, allows to discriminate between superior and inferior quality cooking ware and evaluate the compatibility of the investigated samples with some pottery realised in known manufacturing sites in Lazio. Compositional and petrographic features allow assignment of samples from ‘Villa della Piscina’ testifying productions in the surroundings of Rome, while an importation from outsider workshops is hypothesised for the ceramic fragments from the so called ‘Minerva Medica Temple’. For these, an importation from outsider workshop is hypothesised.
基于比色法、显微拉曼光谱法、扫描电子显微镜法、光学显微镜法和粉末 X 射线衍射法的多种分析方法已被用于研究可追溯到帝国时代（公元一至二世纪）的罗马烹饪器皿样品。特别是对来自两个不同考古遗址（位于 Centocelle 区的 "Villa della Piscina "和位于 Esquilino 区（意大利罗马）的所谓 "Minerva Medica Temple"）的极具特色的陶器进行了研究，对所调查样品的颜色、化学、矿物学和岩相学特征进行了描述，以便对技术和来源方面进行比较。通过比色法对陶瓷碎片进行分类，并结合成分研究和微拉曼光谱分析，可以区分优质和劣质炊具，并评估调查样品与拉齐奥已知制造地点的一些陶器的兼容性。通过成分和岩相特征，可以确定 "Villa della Piscina "的样品为罗马周边地区的产品，而所谓的 "Minerva Medica Temple "的陶瓷碎片则被认为是从外来作坊进口的。对于这些陶瓷碎片，假设是从外来作坊进口的。
{"title":"A multi‐analytical investigation of Imperial (I‐II century AD) Roman cooking ware from ‘Villa della Piscina’ and the so called ‘Minerva Medica Temple’ (Rome, Italy)","authors":"Antonella Privitera, Simone Bernardini, Giancarlo Della Ventura, Paolo Ballirano, Elena Arbolino, Caterina Coletti, Lorenzo Conte, Francesco Pacetti, Simona Morretta, Armida Sodo","doi":"10.1002/jrs.6718","DOIUrl":"https://doi.org/10.1002/jrs.6718","url":null,"abstract":"A multi‐analytical approach based on colourimetry, micro‐Raman spectroscopy, scanning electron microscopy, optical microscopy and powder X‐ray diffraction, has been applied to investigate Roman cooking ware samples dating back to imperial age (I‐II century AD). In particular, the highly distinctive production of pots coming from two different archaeological sites, ‘Villa della Piscina’ at Centocelle district and the so called ‘Minerva Medica Temple’ at Esquilino district (Rome, Italy), was studied characterising the colour, the chemical, mineralogical and petrographic distinctive properties of the investigated samples, in order to compare technological and provenance aspects. Classification of ceramic fragment by colorimetry, integrated by compositional studies with a main contribution of micro‐Raman spectroscopy, allows to discriminate between superior and inferior quality cooking ware and evaluate the compatibility of the investigated samples with some pottery realised in known manufacturing sites in Lazio. Compositional and petrographic features allow assignment of samples from ‘Villa della Piscina’ testifying productions in the surroundings of Rome, while an importation from outsider workshops is hypothesised for the ceramic fragments from the so called ‘Minerva Medica Temple’. For these, an importation from outsider workshop is hypothesised.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141550860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Arianna Passaretti, Luana Cuvillier, Claude‐Alain Künzi, Laura Brambilla, Edith Joseph
Jean Dunand (1877–1942) was a European artist internationally appreciated at his time for his innovative Art Déco housewares made of hammer‐beaten copper‐based alloys, known as dinanderie. Still uncertain was the nature of the constituting materials; therefore, for the first time, three objects, namely, a bowl, a trinket bowl and a vase, were the target of a multi‐modal work of characterisation. Mobile or benchtop X‐ray fluorescence, Fourier‐transform infrared (FTIR) and Raman spectroscopies were used to adapt the analyses to the shape and size of the artefacts. Elemental analysis verified that the vase consisted of brass Cu70Zn30, whereas the bowl and the trinket bowl were made of nickel silver Cu70Zn19Ni11. The black finishing present on all the artefacts was related to tenorite by Raman spectroscopy, ascribing the patina to an intentional artist's willing and not to spontaneous tarnishing processes. Metal soaps of copper and zinc were documented as degradation products by FTIR spectroscopy. The drawings adorning the vase and the trinket bowl were identified as silver‐based, contrary to what was hypothesised by conservators (i.e., tin‐based) due to conventional Dunand's inlaying technique. Besides single‐point analysis, Raman mapping was performed in‐situ, applying for the first time a Virsa™ Raman Analyser (Renishaw) in the field of cultural heritage. The fibre‐optic‐coupled instrument allowed to comply constantly with the artefacts' geometry thanks to the modular probe and the motorised focus‐tracking stand. The synergic combination of elemental and vibrational analyses resulted successful, providing new and unique information on artist's technique in view of possible restoration interventions.
{"title":"Multi‐analytical characterisation of Art Déco dinanderie: Single‐point and map analysis of Jean Dunand's metal artworks","authors":"Arianna Passaretti, Luana Cuvillier, Claude‐Alain Künzi, Laura Brambilla, Edith Joseph","doi":"10.1002/jrs.6712","DOIUrl":"https://doi.org/10.1002/jrs.6712","url":null,"abstract":"Jean Dunand (1877–1942) was a European artist internationally appreciated at his time for his innovative Art Déco housewares made of hammer‐beaten copper‐based alloys, known as <jats:italic>dinanderie</jats:italic>. Still uncertain was the nature of the constituting materials; therefore, for the first time, three objects, namely, a bowl, a trinket bowl and a vase, were the target of a multi‐modal work of characterisation. Mobile or benchtop X‐ray fluorescence, Fourier‐transform infrared (FTIR) and Raman spectroscopies were used to adapt the analyses to the shape and size of the artefacts. Elemental analysis verified that the vase consisted of brass Cu<jats:sub>70</jats:sub>Zn<jats:sub>30</jats:sub>, whereas the bowl and the trinket bowl were made of nickel silver Cu<jats:sub>70</jats:sub>Zn<jats:sub>19</jats:sub>Ni<jats:sub>11</jats:sub>. The black finishing present on all the artefacts was related to tenorite by Raman spectroscopy, ascribing the patina to an intentional artist's willing and not to spontaneous tarnishing processes. Metal soaps of copper and zinc were documented as degradation products by FTIR spectroscopy. The drawings adorning the vase and the trinket bowl were identified as silver‐based, contrary to what was hypothesised by conservators (i.e., tin‐based) due to conventional Dunand's inlaying technique. Besides single‐point analysis, Raman mapping was performed in‐situ, applying for the first time a Virsa™ Raman Analyser (Renishaw) in the field of cultural heritage. The fibre‐optic‐coupled instrument allowed to comply constantly with the artefacts' geometry thanks to the modular probe and the motorised focus‐tracking stand. The synergic combination of elemental and vibrational analyses resulted successful, providing new and unique information on artist's technique in view of possible restoration interventions.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141550862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Flávia C. Marques, Erix A. Milán‐Garcés, Vanessa E. de Oliveira, Stéfanos L. Georgopoulos, Gustavo F. S. Andrade, Luiz Fernando C. de Oliveira
There has been increasing interest in the use of squaraines with different physicochemical properties. However, their applications in nanoplasmonics are limited. For that, detailed information on the interactions of squaraines with plasmonic nanostructures is required. In this work, we have studied the adsorption of the squaraine cis‐dicyanomethylene squarate (CDSQ) on the surface of Ag nanoparticles (AgNP). We have combined normal Raman, surface‐enhanced Raman scattering (SERS), and DFT calculations to get insights into the configuration of its adsorption. DFT calculations have been carried out using simplified models of different adsorption geometries for comparison with the results of the SERS experiments. A comparison between the relative intensities of the normal Raman and SERS spectra indicates that CDSQ is adsorbed perpendicular to the AgNP surface. The predicted spectra suggest that CDSQ is chemically adsorbed on the silver surface through one of its N atoms.
{"title":"Surface‐enhanced Raman scattering of Cis‐(dicyanomethylene) squarate ion on a silver substrate","authors":"Flávia C. Marques, Erix A. Milán‐Garcés, Vanessa E. de Oliveira, Stéfanos L. Georgopoulos, Gustavo F. S. Andrade, Luiz Fernando C. de Oliveira","doi":"10.1002/jrs.6716","DOIUrl":"https://doi.org/10.1002/jrs.6716","url":null,"abstract":"There has been increasing interest in the use of squaraines with different physicochemical properties. However, their applications in nanoplasmonics are limited. For that, detailed information on the interactions of squaraines with plasmonic nanostructures is required. In this work, we have studied the adsorption of the squaraine cis‐dicyanomethylene squarate (CDSQ) on the surface of Ag nanoparticles (AgNP). We have combined normal Raman, surface‐enhanced Raman scattering (SERS), and DFT calculations to get insights into the configuration of its adsorption. DFT calculations have been carried out using simplified models of different adsorption geometries for comparison with the results of the SERS experiments. A comparison between the relative intensities of the normal Raman and SERS spectra indicates that CDSQ is adsorbed perpendicular to the AgNP surface. The predicted spectra suggest that CDSQ is chemically adsorbed on the silver surface through one of its N atoms.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The Raman spectra of ferrocene crystals were measured at pressures up to 20 GPa, and an abnormally large bandwidth of intermolecular phonons at ambient pressure was found. With an increase in the pressure, the bandwidth increased to a maximum at ~2 GPa and then decreased to a minimum at ~4 GPa, which was equal to the pressure‐independent bandwidth of intramolecular phonons. The unusual behavior of the bandwidth was related to the instability of a ferrocene molecule caused by jumps between its D5d and D5h conformations. A decrease in the time of jumps between the conformations to the period of crystal lattice vibrations led to a loss of coherence and broadening of intermolecular phonon bands. The energy barrier between the conformations was determined to be ~17.6 meV/molecule under ambient conditions and 80 meV/molecule at 4.9 GPa. An increase in the barrier with pressure was due to the enhancement of the crystal field, which resulted in the inhibition of the jumps and the stabilization of the molecule in the D5d conformation.
{"title":"Raman study of the conformational instability of a ferrocene molecule at high pressure: Influence of a crystal field","authors":"Konstantin Meletov","doi":"10.1002/jrs.6713","DOIUrl":"https://doi.org/10.1002/jrs.6713","url":null,"abstract":"The Raman spectra of ferrocene crystals were measured at pressures up to 20 GPa, and an abnormally large bandwidth of intermolecular phonons at ambient pressure was found. With an increase in the pressure, the bandwidth increased to a maximum at ~2 GPa and then decreased to a minimum at ~4 GPa, which was equal to the pressure‐independent bandwidth of intramolecular phonons. The unusual behavior of the bandwidth was related to the instability of a ferrocene molecule caused by jumps between its D<jats:sub>5d</jats:sub> and D<jats:sub>5h</jats:sub> conformations. A decrease in the time of jumps between the conformations to the period of crystal lattice vibrations led to a loss of coherence and broadening of intermolecular phonon bands. The energy barrier between the conformations was determined to be ~17.6 meV/molecule under ambient conditions and 80 meV/molecule at 4.9 GPa. An increase in the barrier with pressure was due to the enhancement of the crystal field, which resulted in the inhibition of the jumps and the stabilization of the molecule in the D<jats:sub>5d</jats:sub> conformation.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Macro‐Raman mapping is an approach that is well suited to study the distribution of molecules over a surface of typically several cm2, such as the pigment distribution on a painting. During such an experiment, thousands Raman spectra are recorded in a predefined array of points. As there can be a huge difference in Raman sensitivity between different molecules, an alternative approach is proposed, where measurement times are adapted according to the quality of the Raman scatterer. Therefore, an iterative process is implemented, involving recording short accumulations, followed by a quick evaluation. As soon as the accumulated spectrum reaches a quality criterium, measurement of the next point is started, while in the other case further accumulations are added. The influence of using multiple accumulations opposite to a single measurement for a prolonged period has been assessed by comparing the overall measurement time and the spectral intensity of the main Raman band (520.5 cm−1) of silicon. Another prerequisite for this algorithm to be successful is the need for a quick and reliable evaluation of the spectral quality. This was examined by applying this function on the accumulations of Raman spectra of 49 paint samples from a colour chart. Finally, the variable‐accumulation algorithm is applied during a macro‐Raman mapping experiment of a watercolour painting on paper. Despite a significant gain in overall measuring time, this novel approach yields a qualitative data set that can be used for creating clear Raman maps, using different data processing methods.
{"title":"An alternative macro‐Raman mapping algorithm, adapting the numbers of accumulations","authors":"Peter Vandenabeele","doi":"10.1002/jrs.6715","DOIUrl":"https://doi.org/10.1002/jrs.6715","url":null,"abstract":"Macro‐Raman mapping is an approach that is well suited to study the distribution of molecules over a surface of typically several cm<jats:sup>2</jats:sup>, such as the pigment distribution on a painting. During such an experiment, thousands Raman spectra are recorded in a predefined array of points. As there can be a huge difference in Raman sensitivity between different molecules, an alternative approach is proposed, where measurement times are adapted according to the quality of the Raman scatterer. Therefore, an iterative process is implemented, involving recording short accumulations, followed by a quick evaluation. As soon as the accumulated spectrum reaches a quality criterium, measurement of the next point is started, while in the other case further accumulations are added. The influence of using multiple accumulations opposite to a single measurement for a prolonged period has been assessed by comparing the overall measurement time and the spectral intensity of the main Raman band (520.5 cm<jats:sup>−1</jats:sup>) of silicon. Another prerequisite for this algorithm to be successful is the need for a quick and reliable evaluation of the spectral quality. This was examined by applying this function on the accumulations of Raman spectra of 49 paint samples from a colour chart. Finally, the variable‐accumulation algorithm is applied during a macro‐Raman mapping experiment of a watercolour painting on paper. Despite a significant gain in overall measuring time, this novel approach yields a qualitative data set that can be used for creating clear Raman maps, using different data processing methods.","PeriodicalId":16926,"journal":{"name":"Journal of Raman Spectroscopy","volume":null,"pages":null},"PeriodicalIF":2.5,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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