Institute of Chemistry, Faculty of Science and Technology, University of Tartu, Ravila 14a, 50411 Tartu, Estonia.
Molecules. 2021 Apr 12;26(8):2218. doi: 10.3390/molecules26082218.
In this study, quantitative gas chromatography-mass spectrometry (GC-MS) analysis was used to evaluate the influence of pigment concentration on the drying of oil paints. Seven sets of artificially aged self-made paints with different pigments (yellow ochre, red ochre, natural cinnabar, zinc white, Prussian blue, chrome oxide green, hematite + kaolinite) and linseed oil mixtures were analysed. In the pigment + linseed oil mixtures, linseed oil concentration varied in the range of 10 to 95 g/100 g. The results demonstrate that the commonly used palmitic acid to stearic acid ratio (P/S) to distinguish between drying oils varied in a vast range (from especially low 0.6 to a common 1.6) even though the paints contained the same linseed oil. Therefore, the P/S ratio is an unreliable parameter, and other criteria should be included for confirmation. The pigment concentration had a substantial effect on the values used to characterise the degree of drying (azelaic acid to palmitic acid ratio (A/P) and the relative content of dicarboxylic acids (∑D)). The absolute quantification showed that almost all oil paint mock-ups were influenced by pigment concentration. Therefore, pigment concentration needs to be considered as another factor when characterising oil-based paint samples based on the lipid profile.
在这项研究中，使用定量气相色谱-质谱（GC-MS）分析来评估颜料浓度对油画干燥的影响。分析了七组不同颜料（黄赭石、红赭石、天然朱砂、锌白、普鲁士蓝、氧化铬绿、赤铁矿+高岭土）和亚麻籽油混合物的人工老化自制涂料。在颜料+亚麻籽油混合物中，亚麻籽油浓度在 10 至 95g/100g 范围内变化。结果表明，常用的区分干性油的棕榈酸与硬脂酸比值（P/S）差异很大（从特别低的 0.6 到常见的 1.6），即使涂料中含有相同的亚麻籽油。因此，P/S 比值是一个不可靠的参数，应该包括其他标准进行确认。颜料浓度对用于表征干燥程度的数值有很大影响（壬二酸与棕榈酸的比值（A/P）和二羧酸的相对含量（∑D））。绝对定量表明，几乎所有的油画模拟品都受到颜料浓度的影响。因此，在根据脂质谱表征油性涂料样品时，需要将颜料浓度视为另一个因素。
