Solid-phase extraction based on PDMS/ionic liquid sponge followed by gas chromatography-mass spectrometry for rapid...

Due to the complexity and the low concentrations of volatile components in aromatic plants, sample pretreatment is an important step in the whole analytical procedure.

This study aimed to propose a novel, sensitive and fast approach to determine the volatile components in lavender.

The 1-butyl-3-(propyltrimethoxysilane)imidazolium chloride ([BPtmsim]Cl) ionic liquid was introduced onto the surface of polydimethylsiloxane (PDMS) to prepare a novel PDMS/[BPtmsim]Cl sponge with large surface area, good sorption performance, and reusability. A solid-phase extraction method was developed based on PDMS/[BPtmsim]Cl sponge combined with gas chromatography-mass spectrometry (GC-MS).

The effects of the various experimental parameters on the extraction efficiency were investigated. The optimal conditions were [BPtmsim]Cl amount of 0.3 g, 1:4 as the mass ratio of PDMS/[BPtmsim]Cl to lavender sample, microwave power of 700 W, microwave time of 10 min, and n-hexane as the desorption solvent. The method validation results showed good linearity (10-800 μg/ml), high correlation coefficient (R²  ≥ 0.9991), low limits of detection (1.73-2.50 ng/μl), and limits of quantification (4.10-5.11 ng/μl). The interday and intraday precision with relative standard deviation (RSD) values were below 1.93% and 4.71%, respectively. Under the optimal extraction conditions, 16 lavender samples from three different species were analysed and a total of 57 volatile compounds were identified. The correlation between different species of lavender and volatile components was explored using principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA).

The results showed that PDMS/[BPtmsim]Cl extraction is a rapid, highly efficient, and sensitive technique for the determination of volatile components in complex plant samples.