Authentication of Citronella Oil from Turpentine Oil Using Fourier-Transform Infrared Spectroscopy Followed by Principal Component Analysis and Partial Least Squares Regression

The adulteration of citronella (Cymbopogon winterianus) oil with a cheaper alternative, such as low-grade turpentine oil, is a recurring issue in the essential oil industry, posing risks to product quality and consumer safety. A rapid and non-destructive authentication method is therefore essential for quality control of this product. This study utilized Fourier-transform infrared spectroscopy followed by principal component analysis (PCA) and partial least squares (PLS) regression for qualitative and quantitative authentication of citronella oil mixed with turpentine oil, respectively. Samples were prepared with various adulteration concentrations of citronella oil in turpentine oil (0 to 100