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Analysis of the volatile compounds in Nepeta crispa willd. Using improved HS-SPME-GC-MS and comparison with conventional methods

Azar P. A, Porgham-Daryasari A, Saber-Tehrani M, Soleimani M.

Acta Chromatographica

2012

Vol. 24, no. 1

75--84

In this study, gas chromatography-mass spectrometry (GC-MS) following microwave distillation and solid-phase microextraction (MD-SPME) was developed for the analysis of essential oil compounds in Nepeta crispa. To improve the headspace (HS) method, microwave powers, irradiation times, and SPME fiber coatings were studied. The optimal experiment parameters obtained were 65-μm PDMS/DVB SPME fiber, a microwave power of 400 W, and an irradiation time of 3 min. MD-SPME was compared with headspace solid-phase microextraction (HS-SPME) and conventional hydrodistillation (HD) for the extraction of essential oil compounds in N. crispa. A comparative qualitative and quantitative study on the composition of the oils was carried out. For this, 26 compounds, constituting 98.2% of the oil, were identified in the essential oil by MD-SPME, and 23 compounds, representing 91.3% of the oil, were characterized in the SPME and HD methods; 25 compounds, constituting 94.6% of the oil, were separated and identified. The main compounds identified by all methods were 1,8-cineol, β-bourbonene, α-terpineol, and β-pinene. The relative standard deviation (RSD) values of less than 8% show that the MD-SPME method has good repeatability.It has been shown that the extraction of essential oils from N. crispa with MD-SPME was better in terms of energy saving, extraction time, plant material, oxygenated fractions, and product quality.

Analysis of tributyltin and triphenyltin in water by ionic liquid-headspace single-drop microextraction then HPLC with fluorimetric detection

Sheikhloie H, Saber-Tehrani M, Abrumand-Azar P, Waqif-Husain S.

Acta Chromatographica

2009

Vol. 21, no. 4

577--589

A novel method using ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C 4 MIM][PF 6 ] as extracting solvent in head-space single drop microextraction followed by HPLC with fluorimetric detection has been developed for analysis of tributyltin (TBT) and triphenyltin (TPhT) in water. Experimental conditions related to SDME performance, for example micro-drop volume, extraction time, stirring rate, salt content, and sample volume were investigated. Under the optimized conditions (micro-drop volume, 10 μL; extraction time, 30 min; stirring rate, 900 rpm; salt concentration, 6%; sample volume, 6 mL), the linear range, detection limit ( S / N = 3), and reproducibility (RSD, n = 4) were 1−100 μL -1, 0.62 μL -1, and 7.8%, respectively, for TBT, and 2−100 μL -1, 0.95 μL -1, and 8.3% for TPhT. All micro-extraction experiments were performed at room temperature (25 ± 1°C). The optimized procedure was successfully used for analysis of TBT and TPhT in deionized water and waste water. Recovery of a 25 μL -1 spike was in the range 86.9–92.1%. The method has also been used for analysis of TBT and TPhT in natural water.