Extraction of Citrus paradisi Volatile Components by Headspace Single-Drop Microextraction and Statistical Modeling

In present study, headspace single-drop microextraction (HS-SDME) was applied for the extraction and preconcentration of the volatile components of the plant sample into a microdrop surface. The extraction occurred by suspending a microliter drop of the solvent from the tip of a microsyringe to the headspace of a ripe fruit sample (grapefruit Citrus paradisi) in a sealed vial for a preset extraction time. Then the microdrop was retracted back into the microsyringe and injected directly into a gas chromatography injection port. The chemical composition of the SDME extracts was confirmed according to their mass spectra, and quantitative analysis was performed by gas chromatography-flame ionization detector (GC-FID). Response surface methodology along with Box-Behnken design was applied to optimize the extraction condition of four components, d-limonene, β-myrcene, α-pinene and β-pinene, from the peel of grapefruit. Parameters considered for SDME include the kind of the extracting solvent, size of drop, extraction temperature and extraction time. The optimized condition was microdrop volume of 1 µL, extraction time of 2 min and sample temperature of 50°C.