Paints identification

Physical match Observation of fit between two chips of paint Only positive form of paint identification a physical match is regarded as the equivalent of a fingerprint ... 

In 1990, the U.S. HUD issued interim guidance for lead paint identification and abatement methodologies for public and Indian housing under the above LBPPPA Amendments (55 FR 14556-14614). These guidelines were addressed to testing for lead-based paint, criteria for lead paint abatement contractor selections, specific lead paint abatement criteria and methodologies, cleanup postabatement, and waste disposal. 

Dei et aL (1998) Dei, L. Able, A. Baghoni, R Dini, D Ferroni, E. Green degradation products of azurite in wall paintings identification and conservation treatment Studies in Conservation 43 (1998) 80-88... 

In a number of cases, identifications have been extremely difficult, because the materials were synthetic and knowledge of their existence had actually been lost. For example, several rather commonly encountered synthetic pigments, such as the lead-tin yellow often found in Renaissance and Baroque paintings, were originally misidentified or left unidentifiable until extensive research, including analyses of elemental composition and chemical and physical properties, and repHcation experiments, led to proper identification of the material and its manufacturing process. 

Eor many pigments, a period of time in which they had their widest use can be indicated (54,62,63). Dates of introduction are known either from documentary sources or from identification on paintings of known dates. Eor some pigments, an approximate date for the discontinuation of use can be assigned. In some cases, knowledge of the preparation process or even the very existence was lost over an appreciable time span. 

Testing of phthalocyanines includes crystallization (qv), flocculation, and appHcation in paints, plastics (qv), and printing inks (1). The ASTM standard specifications include CuPc in dry powder form for various appHcations (153). The specifications cover color (qv), character or tint, oil absorption, reactions in identification tests, and dispersions and storage stabiUty. Quantitative deterrninations are possible with ceric sulfate (30) or sodium vanadate (154). Identification methods are given (155), including tests for different appHcations. 

Gooch [4] has reported general deformulation schemes for solid paints and coatings, liquid paints, solid plastics, liquid plastic specimens, solid and liquid adhesives, in which preliminary examination (by OM, SEM, EDXRA) is followed by separation of the individual components and their subsequent identification (Scheme 2.9). Gooch employs different deformulation schemes for solid and liquid specimens, but essentially identical approaches for plastics, paints, adhesives and inks (Scheme 2.10). 

Despite these numerous advantages, mass spectrometry has often been used more as an auxiliary, rather than a primary, identification method for additives in polymers, paints, coatings, etc. Nevertheless, mass spectrometry can be used for direct determination of the composition of unknown admixtures. More difficult is the MS examination of substances of low volatility, as the sample has to be introduced in the gas phase. This requires volatilisation, which often leads to fragmentation. 

The use of Raman microscopy in the detection and identification of pigments on manuscripts, paintings, ceramics and papyri was reviewed by Clark (1999). He concludes that it is arguable the best single technique to be applied to this area, since it combines the attributes of reproducibility and sensitivity with those of being nondestructive and immune to interference from both pigments and binders. He points... 

Burgio, L., R. J. H. Clark, T. Stratoudaki, M. Doulgeridis, and D. Anglos (2000), Pigment identification in painted artworks A dual analytical approach employing LIBS (laser-induced breakdown spectroscopy) and Raman microscopy, Appl. Spectrosc. 54(4), 463-469. 

Shirono, S. and Y. Hayakawa (2006), Identification of painting materials used for mural paintings by image analysis and XRF, Adv. in X-Ray Anal. 49, 213-217. 

The spray paint can was inverted and a small amount of product was dispensed into a 20 mL glass headspace vial. The vial was immediately sealed and was incubated at 80°C for approximately 30 min. After this isothermal hold, a 0.5-mL portion of the headspace was injected into the GC/MS system. The GC-MS total ion chromatogram of the paint solvent mixture headspace is shown in Figure 15. Numerous solvent peaks were detected and identified via mass spectral library searching. The retention times, approximate percentages, and tentative identifications are shown in Table 8 for the solvent peaks. These peak identifications are considered tentative, as they are based solely on the library search. The mass spectral library search is often unable to differentiate with a high degree of confidence between positional isomers of branched aliphatic hydrocarbons or cycloaliphatic hydrocarbons. Therefore, the peak identifications in Table 8 may not be correct in all cases as to the exact isomer present (e.g., 1,2,3-cyclohexane versus 1,2,4-cyclohexane). However, the class of compound (cyclic versus branched versus linear aliphatic) and the total number of carbon atoms in the molecule should be correct for the majority of peaks. 

The FTIR spectrum for the dried paint resin does have a reasonable match score to and feature bands characteristic of an alkyd resin [5]. Due to the presence of fillers though, the spectral analysis did not allow for a high-quality match to be obtained. Removal of the fillers and subsequent FTIR analysis would provide the best spectroscopic result for the identification of the alkyd type and provide a better comparison to such as the reference vinyl toluene-modified alkyd. 

Yellow Lake Pigments, Identification and Study of Deterioration of Flavonoid Colorants. Arie Wallert and N. Wyplosz, Molecular Aspects of Ageing in Painted Works of Art, Progress Report 1995-1997, FOM Institute for Atomic and Molecular Physics, Amsterdam, NL, http //www.amolf.nl/research/biomacromolecular mass spectrometry/ molart/progress report98.pdf... 

Anglos D., Couris S., Fotakis C., Laser Diagnostics of Painted Artworks Laser-Induced Breakdown Spectroscopy in Pigment Identification, Appl. Spectrosc. 1997 51(7) 1025. 

Bussotti L., Castellucci E., Matteini M., The Micro-Raman Technique in the Studies for the Conservation of Art Works Identification of Lakes in Paints, Science and Technology for Cultural Heritage 1996 5 (1) 13. 

S. Keck, T. Peters, Identification of protein containing paint media by quantitative amino acid analysis, Studies in Conservation, 14, 75 82 (1969). 

J.S. Mills, The gas chromatographic examination of paint media. Part I Fatty acid composition and identification of dried oil films, Studies in Conservation, 11, 92 107 (1966). 

J.S. Mills, R. White, The identification of paint media from the analysis of their sterol composition, Studies in Conservation, 20, 176 182 (1975). 

According to the predominant component, the binders are usually divided into protein, oil, polysaccharide, and resin binders. In this section we shall focus on protein binders but it is worth mentioning that in the majority of natural non-protein binders a minority protein component is usually present as well. Thus many of the analytical techniques described here can be (with certain limitations) applied to them as well. Although in colour layers of artworks and particularly in paintings protein binders are relatively abundant (up to 10%), their identification is often limited by a small amount of sample that is usually available for analysis (tens or hundreds of micrograms at most [6]). 

I. Gluch, A. Urbanska, I. Zadrozna, K. Pawlak, M. Jarosz, Identification of proteinaceous binding media used for paintings by capillary electrophoresis with electrospray MS detection, Chem. Analit., 51, 195 210 (2006). 

R. Hynek, S. Kuckova, J. Hradilova, M. Kodicek, Matrix assisted laser desorption/ionization time of flight mass spectrometry as a tool for fast identification of protein binders in color layers of paintings, Rapid. Commun. Mass Spectrom., 18, 1 5 (2004). 

C. Tokarski, E. Martin, Ch. Rolando, C. Cren Olive, Identification of proteins in Renaissance paintings by proteomics, Anal. Chem., 78, 1494 1502 (2006). 

The analysis of paint samples represents a peculiar case, in which the identification of lipids is made virtually possible by the fact that the range of used materials is limited to drying oils (linseed, poppy seed, walnut, tung), egg yolk, and beeswax. Safflower oil (from... 

The analytical techniques proposed in the literature generally give reliable information on lipids present in the paint layer. However, the presence of lipid mixtures and of particular environmental conservation conditions may affect the lipid pattern to such an extent that their identification may be very difficult and sometimes erroneous. Thus, a multianalytical approach is recommended which integrates chromatographic data with techniques such as mapping based on Fourier transform infrared spectroscopy or SIM on cross-sections, in order to better understand the distribution of lipids in the various paint layers. 

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