The research revealed that all the symmetrical ionic liquids studied exhibit excellent thermal stability. Besides, the hydrophobicity and viscosity of the ionic liquid increase and its density and polarity decrease with the increase of the alkyl chain length in the imidazole ring. To investigate the extraction performance of different ionic liquid for five esters flavors, the ionic liquid was chosen as the extractant for headspace single-drop microextraction (HS-SDME) in this study. The results showed that the extraction efficiency depend not only on the viscosity, hydrophobicity and polarity of the ionic liquid, but also on the structure and properties of the analyte. Since the ionic liquid 1,3-di-n-butylimidazolium hexafluorophosphate abbreviated as [DC 4 -IM][PF 6 ] offers obviously better extraction efficiency than other ionic liquids, it was selected as headspace drop. Moreover, experimental parameters for the extraction and analysis were also optimized based on the coupling with gas chromatography-mass spectrometry. Under optimal conditions, i.e. the headspace volume of [DC 4 -IM][PF 6 ] 1.0 μL, the concentration of salt 0.36 g/mL , reaction temperature of 40 ℃, reaction time 35 min and desorption 1 min at 250 ℃, the enrichment factors and detection limits were in the range of 260-1429 and 0.46-16.1 μg/L for the five esters, respectively. This method has been applied to simultaneous determination of five esters in natural flavors such as rose oil, rose absolute and jasmin absolute, and the recoveries of standard additives varied in the range of 93.8%-108.9%. The fact confirmed that the proposed method is of high sensitivity and good precision.

Cotinus coggygria Scop. as a precious landscape shrub and a good afforestation species that is used in the pharmaceutical industry. In this paper, TG-FTIR, TG-DTG, and Py-GC/MS were used to study the biomaterials of Cotinus coggygria used as biofuels and biochemicals under the catalysis of nano-Mo/Fe2O3. The wood powder was extracted using a methanol/benzene solution, and the extract was analyzed by FTIR and GC-MS. The results showed that the pyrolysis products of Cotinus coggygria wood were rich in phenols, alcohols, and biofuels. The metal nano-Mo powder played a catalytic role in the interpretation of the gas in the species, where it accelerates gas products. Metal nano-Fe2O3 has a certain flame-retardant effect on the burning process of Cotinus coggygria wood, and the residual amount of pyrolysis is greater. The contents of the extract Formamide, 1-Hexanol, Levodopa, and 9,12-Octadecadienoic acid (Z,Z)- are not only widely used industrially but also play an important role in medicine. Cotinus coggygria is therefore an excellent biomaterial for biofuels and biochemicals.