A method employing the direct immersion solid-phase microextraction followed by GC-MS analysis is presented for the determination of essential oils components in herbal tea infusions, i.e. their direct content in the liquid phase. The extraction performances were compared using five different microextraction fibres. Significant parameters affecting sorption process such as sample amount, sorption and desorption time and temperature, stirring speed, pH adjustment and effect of ionic strength were optimised and discussed. By optimising the key parameters, a detection limits (LOD = S/N × 3) for ten target marker compounds were obtained in the range from 5.3 to 48.2 ng/mL with recoveries ranged between 93.03 and 100.50%. Intra-day and inter-day repeatability at three concentration levels were found to be 1.1-15.3 and 7.2-15.5% RSD, respectively. Finally, the optimised procedure enabling a rapid and simple analysis of essential oils was applied for the direct determination of these compounds in ten herbal tea infusions.

• MeSH
• Solid Phase Microextraction methods   MeSH
• Beverages analysis   MeSH
• Oils, Volatile analysis   isolation & purification   MeSH
• Gas Chromatography-Mass Spectrometry MeSH
• Publication type
• Journal Article MeSH
• Evaluation Study MeSH

A method employing the headspace single-drop microextraction (HS-SDME) is presented for the determination of essential oils in dried herbal leaves. By optimising the key experimental parameters, a linear response for the individual target compounds was obtained in the concentration range from LOQ to 4 mg/mL (r(2) = 0.9912-0.9998), with LODs from 3.3 up to 20.5 microg per 100 g of dried leaves, and the repeatability within the RSD of 2.1-8.9%. The HS-SDME-based procedure, enabling a rapid and simple analysis of essential oils in herbs, was applied to selected real samples (nine essential oils in four different samples) in combination with GC-FID identification and quantification of the target volatiles.

• MeSH
• Chromatography, Gas methods   MeSH
• Financing, Organized MeSH
• Oils, Volatile analysis   MeSH
• Temperature MeSH
• Publication type
• Validation Study MeSH

• MeSH
• Chemistry Techniques, Analytical methods   standards   MeSH
• Solid Phase Extraction methods   standards   utilization   MeSH
• Research Support as Topic MeSH
• Financing, Organized MeSH
• Chemistry, Physical methods   standards   MeSH
• Clinical Laboratory Techniques standards   utilization   MeSH
• Organic Chemicals chemistry   isolation & purification   standards   MeSH
• Solvents analysis   chemistry   MeSH