A method for the extraction and quantification of limonene from citrus fruit peels is discussed in this applications note. Beyond demonstrating the use of GC/MS in the analysis of citrus fruit for limonene content, this application demonstrates a simple, inexpensive technique to introduce students to method development, calibration and quantification using a chromatographic technique. The analysis of citrus fruit for limonene may be an ideal laboratory assignment at the undergraduate level. The techniques used are safe, simple and easy.
The extraction and quantification of limonene from citrus rinds using GC/MS
D-Limonene, shown in Figure 1, is a common naturally occurring compound with a citrus scent. It is often used as an additive in food products and fragrances, and is classified by the U.S. Food and Drug Administration (FDA) as Generally Recognized as Safe (GRAS)1. It has also been approved by the U.S. Environmental Protection Agency (EPA) for usage as a natural pesticide and insect repellent1. Limonene has also been studied for its anti-arcinogenic properties2. Orange oil, which contains a considerable amount of limonene, has numerous applications including a combustant in engines3, a powerful degreaser in cleaning applications, and a natural pesticide4. These uses may require a known concentration of limonene with a limited amount of impurities. This exemplifies the need for a reliable method of extraction of limonene from its natural source, citrus rinds, followed by a quantitative analysis of the extract for limonene and possible impurities.