Detection of Ethanol Adulteration in Citronellal Oil by using Near Infared Spectroscopy and Multivariate Data Analysis

Citronella oil is one of the essential oils obtained from the leaves and stems of different species of Cymbopogon. The oil is used extensively as a source of perfumery chemicals such as citronellal, citronellol and geraniol. These chemicals are use in soap, perfumery, cosmetic, flavouring industries and also insect repellent throughout the world. The objective of this study is to use Near Infrared Spectroscopy (NIRS) as a rapid analytical technique for quantitative assessment of purity in citronella oils. At first, the potential of NIRS in controlling and monitoring the quality of essential oil was investigated by diluting ethanol in different concentration as perturbation. Partial Least Square (PLS) regression method was used as a mathematical approach to detect and quantify ethanol. A number of wavelength ranges and data pretreatments were explored. The accuracy of these mathematical models was compared, and the most successful models were identified. The results demonstrate that NIRS technology was useful in the rapid and accurate detect and quantify ethanol in citronella oil.