Use of Attenuated Total Reflection Fourier Transform Infrared Spectroscopy and Principal Component Analysis for the Assessment of Engine Oils

Attenuated total reflection Fourier transform infrared spectroscopy coupled with principal component analysis was used to investigate expensive and low-priced engine oil samples. A total of 174 oil samples of 15 commercial brands (expensive and low-priced) was successfully differentiated into five viscosity grades. The percentage of successful clustering of these oils ranged from 70.6 to 100%. The viscosity grades of oils of each commercial brand were also successfully distinguished for 10 different commercial brands. The successful clustering for this ranged from 72.5 to 100% for the 159 studied oil samples. Moreover, 15 low-priced oil samples of five commercial brands were assessed with 100% accuracy.