Combined GC/MS Analytical Procedure for the Characterization of Glycerolipid, Waxy, Resinous, and Proteinaceous Materials in a Unique Paint Microsample

Abstract

A novel GC/MS analytical procedure for the identification of lipids, waxes, proteins, and resinous materials in the same microsample from painted works of art has been optimized. It is based on a sample multistep chemical pretreatment (solvent extractions and microwave-assisted chemolysis) that is able to separate the various organic components into different fractions, which are suitably treated and derivatized before analysis. In particular, the procedure allows the complete saponification of wax esters and the completeness of the Cannizzaro type reaction of shellac acids in conditions that are suitable also for glycerides saponification. The method was tested on reference materials for the identification of proteinaceous binders (egg, collagen, casein) on the basis of the quantitative determination of the amino acid profile and the identification of glycerolipids (linseed oil, poppy seed oil, walnut oil, and egg), plant resins (Pinaceae resins, sandarac, mastic, and dammar), animal resins (shellac), tars or pitches, and natural waxes (beeswax, carnauba wax) on the basis of the determination of fatty acid, alcohol, and hydrocarbon profiles and of significant terpenic molecular markers. The procedure was applied to the characterization of three old paint microsamples. Animal glue, egg, linseed oil, beeswax, Pinaceae resin, dammar, and shellac were the identified materials found in mixtures and recognized as original and/or restoration substances.

Yield and Characteristics of Pyrolysis Products Obtained from Schizochytrium limacinum under Different Temperature Regimes

“…Both soluble organic compounds in liquid and solid pyrolysis products can be conveniently determined by high performance liquid chromatography (HPLC) or gas chromatography (GC). By collecting a number of products over different stages of pyrolysis, retention times and the peak area percentages characteristic to each product can be automatically calculated and recorded by GC-MS [17][18][19][20]. Further data or profiles such as the absolute intensity and concentration level can also be automatically calculated by integration and by comparing against standard material databases, such as the NIST (National Institute of Standards and Technology) library.…”

The chemical-physical knowledge before the restoration: the case of “The Plague in Lucca”, a masterpiece of Lorenzo Viani (1882–1936)

“…The hydroxyproline is an indicator of animal glue presence: a quite high content in samples 1 and 4, lower in samples 2 and 3 [28][29][30]. The relative amino acid content in the samples was compared with 121 reference samples using the Principal Component Analysis (PCA) method, which confirms the presence of animal glue (see Fig.…”

The analysis of constituent materials of the naos doors belonging to the wooden church from Petrindu, Salaj County

“…One speeks on the electronic microscopy (SEM), X-ray fluorescence (XRF), gas and liquid chromatography coupled with massspectrometry, Raman and IR spectroscopy, etc. [4,5]. Petrindu wooden church has a door separating the narthex and nave (Fig.1).…”