Analysis of Volatile Components in Lavender Using PDMS/GO@Fe₃O₄ Sponge Headspace Solid Phase Extraction Combined with GC-MS

Lavender (Lavandula angustifolia Mill.) is an aromatic herb that belongs to the Labiatae family, which is native to world. In recent years, lavender is widely cultivated in Xinjiang of China. A novel PDMS/GO@Fe₃O₄ sponge headspace solid-phase microextraction (HS-PDMS/GO@Fe₃O₄) using microwave distillation followed by GC-MS was developed to determine the essential oil components in lavender. The PDMS/GO@Fe₃O₄ sponge was successfully synthesized. The prepared PDMS/GO@Fe₃O₄ was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The PDMS/GO@Fe3O4 sponge with high surface area and excellent adsorption capacity were successfully applied in the solid phase extraction process. The effective parameters of HS-PDMS/GO@Fe3O4, including the dosage of GO@Fe₃O₄, microwave power, microwave time and type of extraction solvent, were studied and optimized in detail. A single factor method was used to select the optimum extraction conditions in HS-PDMS/GO@Fe₃O₄. The optimal analytical conditions were as follows: GO@Fe₃O₄ dosage of 2.4 mg, microwave power of 600 W, microwave time of 10 min, and n-hexane as extraction solvent. The precision of HS-PDMS/GO@Fe₃O₄ was evaluated and the relative standard deviation (RSD) for determining six representative compounds were below 6.36%. The linearity was good, and the correlation coefficient was more than 0.998 8. The limits of detection (LODs) ranged from 0.14 to 0.33 ng, and the limits of quantification (LOQs) ranged from 0.50 to 0.80 ng, respectively. Only 10 mg of lavender sample was needed in each analysis. The result showed that a total of 18 samples from two different harvest years were analyzed and 52 compounds were identified. The results were further processed with a discriminative study by principal component analysis (PCA) to reveal the relationship among different samples. PCA provided a clear separation between those lavender samples harvested in different years. This method is fast, simple and sensitive for the determination of volatile components in natural products.