Abstract This study employed Raman spectroscopy for the identification of spectral differences in automotive lubricant oils with different SAE specifications. Samples of 18 lubricant oils were obtained from a local auto parts store. Spectra were obtained with a dispersive Raman spectrometer (830 nm) and separated according to the type of base oil in the samples: mineral, semi-synthetic and synthetic. Also, samples were separated according to the SAE specifications regarding the viscosity grade in low and high temperatures. Principal component analysis (PCA) showed that the lubricants with mineral base oils presented peaks referred to aromatic hydrocarbons and additives containing aromatics, sulfites/dissulphites and sulfonates, while semi-synthetic and synthetic base oils presented peaks referred to alkanes. Other peaks referred to alkanes and olefins were also seen in synthetic base oils. The discriminant analysis based on quadratic distance applied to the PCA variables was able to discriminate the lubricant samples according to the type of base oil with 89.7% accuracy and discriminate the SAE viscosity grade for low and high temperatures with 95.8% and 90.0% accuracy, respectively. The use of Raman spectroscopy makes possible nondestructive evaluation of lubricant oils, which may replace expensive and complex traditional tests and methods of quality control.

中文翻译：

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用于识别与 SAE 规格和添加剂相关的汽车润滑油成分差异的拉曼光谱

摘要 本研究采用拉曼光谱来识别具有不同 SAE 规格的汽车润滑油的光谱差异。18 种润滑油的样品来自当地一家汽车零部件商店。光谱是用分散拉曼光谱仪 (830 nm) 获得的，并根据样品中基础油的类型进行分离：矿物油、半合成油和合成油。此外，根据关于低温和高温下粘度等级的 SAE 规范分离样品。主成分分析（PCA）表明，矿物基础油的润滑油出现的峰是指芳香烃和含有芳烃、亚硫酸盐/二亚硫酸盐和磺酸盐的添加剂，而半合成和合成基础油的润滑油出现的峰是指烷烃。在合成基础油中也发现了其他与烷烃和烯烃有关的峰。基于应用于 PCA 变量的二次距离的判别分析能够根据基础油的类型以 89.7% 的准确度区分润滑油样品，并分别以 95.8% 和 90.0% 的准确度区分低温和高温的 SAE 粘度等级. 拉曼光谱的使用使得对润滑油的无损评估成为可能，这可能会取代昂贵且复杂的传统质量控制测试和方法。7% 的准确度，并分别以 95.8% 和 90.0% 的准确度区分低温和高温的 SAE 粘度等级。拉曼光谱的使用使得对润滑油的无损评估成为可能，这可能会取代昂贵且复杂的传统质量控制测试和方法。7% 的准确度，并分别以 95.8% 和 90.0% 的准确度区分低温和高温的 SAE 粘度等级。拉曼光谱的使用使得对润滑油的无损评估成为可能，这可能会取代昂贵且复杂的传统质量控制测试和方法。