Rapid Analysis of the Essential Oil of Acorus tatarinowii Schott by Microwave Distillation, SPME, and GC-MS

The dry rhizome of Acorus tatarinowii Schott is a traditional Chinese medicine (TCM) which has been used to treat many diseases, for example epilepsy, for thousands of years. In this work, microwave distillation and simultaneous solid-phase microextraction (MD-SPME) were used for analysis of the essential oil in the fresh leaves of Acorus tatarinowii. Isolation, extraction, and concentration of the volatile constituents of the leaves can be completed rapidly, in a single step, by use of MD-SPME; the compounds can then be analyzed by gas chromatography-mass spectrometry (GC-MS). MD-SPME conditions, including microwave power, irradiation time, and SPME fiber coating, were studied. By use of MD-SPME-GC-MS twenty-nine compounds were identified, for the first time, in the essential oil of the plant leaves; the compounds were the same as those in the rhizomes. This suggests the leaves of the plant might be used as a TCM. To demonstrate the feasibility of the method, conventional steam distillation (SD) was also used for extraction of the essential oil from the leaves. The same compounds, in similar amounts, were identified by both methods, confirming the MD-SPME method is highly reliable. Compared with SD, MD-SPME required less time (only 2 min), less sample (1.0 g), and no organic solvent. These results are indicative of the suitability of MD-SPME-GC-MS for simple, rapid, and solvent-free analysis of plant essential oils.     

Rapid determination of essential oil compounds in Artemisia Selengensis Turcz by gas chromatography-mass spectrometry with microwave distillation and simultaneous solid-phase microextraction

In the work, for the first time, two solvent-free sample preparation techniques of microwave distillation (MD) and solid-phase microextraction (SPME) were combined, and developed for determination of essential oil compounds in traditional Chinese medicine (TCM). Using the proposed method, isolation, extraction and concentration of TCM essential oil compounds can be carried out in a single step. To demonstrate its feasibility, MD-SPME was compared with a conventional technique, steam distillation (SD), for gas chromatography-mass spectrometry (GC-MS) analysis of essential oil compounds in a TCM, Artemisia Selengensis Turcz. Forty-nine compounds in the TCM were separated and identified by the present method, while only 26 compounds were detected by SD method. Relative standard deviation (R.S.D.) values less than 9% show that the present method has good precision. The SD method required long time (6 h) to isolate of the essential oil, and large amount of organic solvent for further extraction, while MD-SPME needed little time (only 3 min) to prepare sample, and no organic solvent. These results show that MD-SPME-GC-MS is a simple, rapid and solvent-free method for determination of TCM essential oil.     

Rapid analysis of the essential oil components of dried Zanthoxylum bungeanum Maxim by Fe2O3‐magnetic‐microsphere‐assisted microwave distillation and simultaneous headspace single‐drop microextraction followed by GC–MS

In this work, microwave distillation assisted by Fe₂O₃ magnetic microspheres (FMMS) and headspace single‐drop microextraction were combined, and developed for determination of essential oil compounds in dried Zanthoxylum bungeanum Maxim (ZBM). The FMMS were used as microwave absorption solid medium for dry distillation of dried ZBM. Using the proposed method, isolation, extraction, and concentration of essential oil compounds can be carried out in a single step. The experimental parameters including extraction solvent, solvent volume, microwave power, irradiation time, and the amount of added FMMS, were studied. The optimal analytical conditions were: 2.0 μL decane as the extraction solvent, microwave power of 300 W, irradiation time of 2 min, and the addition of 0.1 g FMMS to ZBM. The method precision was from 4 to 10%. A total of 52 compounds were identified by the proposed method. The conventional steam distillation method was also used for the analysis of essential oil in dried ZBM and only 31 compounds were identified by steam distillation method. It was found that the proposed method is a simple, rapid, reliable, and solvent‐free technique for the determination of volatile compounds in Chinese herbs.     

Development of gas chromatography-mass spectrometry following microwave distillation and simultaneous headspace single-drop microextraction for fast determination of volatile fraction in Chinese herb

In this work, for the first time, microwave distillation (MD) coupled with simultaneous headspace single-drop microextraction (HS-SDME) was developed for the determination of the volatile components in the Chinese herb, Artemisia capillaris Thunb. The volatile components were rapidly isolated by MD, and simultaneously extracted and concentrated by using a dodecane microdrop. The volatile oil extracted in the microdrop solvent was analyzed by gas chromatography-mass spectrometry (GC-MS). The experimental parameters of solvent selection, microdrop volume, microwave power, irradiation time and sample amount were investigated, and the method precision was also studied. The optimal parameters were extraction solvent of dodecane, solvent volume of 2.0 microL, microwave power of 400 W, irradiation time of 4 min, and sample amount of 2.0 g. Thirty-five volatile compounds present in Artemisia capillaris Thunb. were identified by using the proposed method, which were identical with those obtained by the conventional steam distillation method. The experimental results showed that MD-HS-SDME is a simple, rapid, reliable, and solvent-free technique for the determination of volatile compounds in Chinese herbs.     

Analysis of volatile oil composition of Citrus aurantium L. by microwave‐assisted extraction coupled to headspace solid‐phase microextraction with nanoporous based fibers

Nanoporous silica was prepared and functionalized with amino propyl‐triethoxysilane to be used as a highly porous fiber‐coating material for solid‐phase microextraction (SPME). The prepared nanomaterials were immobilized onto a stainless steel wire for fabrication of the SPME fiber. The proposed fiber was evaluated for the extraction of volatile component of Citrus aurantium L. leaves. A homemade microwave‐assisted extraction followed by headspace (HS) solid‐phase apparatus was used for the extraction of volatile components. For optimization of factors affecting the extraction efficiency of the volatile compounds, a simplex optimization method was used. The repeatability for one fiber (n = 4), expressed as RSD, was between 3.1 and 8.6% and the reproducibility for five prepared fibers was between 10.1 and 14.9% for the test compounds. Using microwave‐assisted distillation HS‐SPME followed by GC‐MS, 53 compounds were separated and identified in C. aurantium L., which mainly included limonene (62.0%), linalool (7.47%), trans‐β‐Ocimene (3.47%), and caryophyllene (2.05%). In comparison to a hydrodistillation method, the proposed technique could equally monitor almost all the components of the sample, in an easier way, which was rapid and required a much lower amount of sample.     

GC-MS of volatile components of Schisandra chinensis obtained by supercritical fluid and conventional extraction

In this paper, the volatile compounds of Schisandra chinensis obtained by different extraction techniques including supercritical fluid extraction (SFE), steam distillation (SD), Soxhlet extraction (SE) and ultrasound-assisted extraction (UAE) were investigated for the first time. The sample preparation procedure for GC-MS analysis of the volatile compounds was optimized and then 37, 45, 27 and 37 compounds were identified in the samples obtained by SFE, SD, SE and UAE methods, respectively. As the therapeutic effect of the traditional Chinese medicine is usually based on multifarious essential components or the combination of them instead of only one component, the volatile compounds were compared in groups with the extracts by SE, SD and UAE. This would be more reasonable to evaluate the effects of an alternative technique to extracting multifarious essential components. Among the identified components in the SFE extract, 32 compounds were the same as that by three conventional methods, accounting for 90.5% of the volatile compounds identified. However, as the volatile compounds were classed into groups, it was easy to see that the Schisandra chinensis oil extracted by SFE was made up largely of aromatics and sesquiterpenoids (52.1 and 27.6%, respectively), with less amounts of monoterpenoids and other compounds, distinguishing SFE from the conventional extractions.     

微波蒸馏-固相微萃取-气相色谱-质谱-嗅觉检测器联用分析鳙鱼鱼肉中的挥发性成分

用微波蒸馏(MD)-固相微萃取装置(SPME)提取鳙鱼鱼肉中的挥发性成分,利用气相色谱-质谱联用仪(GC-MS)对气味化合物成分进行了定性分析,同时利用嗅觉检测器鉴别了部分挥发性物质的气味特征。实验中优化了MD的操作条件(加热功率、加热时间及载气流速等)、SPME参数(萃取头种类、萃取温度、萃取时间、无机盐离子浓度及搅拌速率等)。通过NIST 02质谱数据库检索共定性确定出鳙鱼鱼肉挥发性成分中的53种化合物,其中主要为 C6~C9 的羰基化合物和挥发性醇类。经过嗅觉检测器分析,这些成分分别具有青草味、鱼腥味、泥土味等气味特征,其协同作用构成了鳙鱼鱼肉特殊的鱼腥味、泥腥味。该方法可用于水产品中挥发性成分的分析,并可为不良风味化合物的定量研究提供参考。     

“In situ” extraction of essential oils by use of Dean–Stark glassware and a Vigreux column inside a microwave oven: a procedure for teaching green analytical chemistry

One of the principal objectives of sustainable and green processing development remains the dissemination and teaching of green chemistry in colleges, high schools, and academic laboratories. This paper describes simple glassware that illustrates the phenomenon of extraction in a conventional microwave oven as energy source and a process for green analytical chemistry. Simple glassware comprising a Dean-Stark apparatus (for extraction of aromatic plant material and recovery of essential oils and distilled water) and a Vigreux column (as an air-cooled condenser inside the microwave oven) was designed as an in-situ extraction vessel inside a microwave oven. The efficiency of this experiment was validated for extraction of essential oils from 30 g fresh orange peel, a by-product in the production of orange juice. Every laboratory throughout the world can use this equipment. The microwave power is 100 W and the irradiation time 15 min. The method is performed at atmospheric pressure without added solvent or water and furnishes essential oils similar to those obtained by conventional hydro or steam distillation. By use of GC-MS, 22 compounds in orange peel were separated and identified; the main compounds were limonene (72.1%), β-pinene (8.4%), and γ-terpinene (6.9%). This procedure is appropriate for the teaching laboratory, does not require any special microwave equipment, and enables the students to learn the skills of extraction, and chromatographic and spectroscopic analysis. They are also exposed to a dramatic visual example of rapid, sustainable, and green extraction of an essential oil, and are introduced to successful sustainable and green analytical chemistry.     

Comparison of solid-phase microextraction, supercritical fluid extraction, steam distillation, and solvent extraction techniques for analysis of volatile consituents in Fructus Amomi

Four sampling techniques, solid-phase microextraction (SPME), supercritical fluid extraction (SFE), steam distillation (SD), and solvent extraction (SE), were compared for the analysis of volatile constituents from a traditional Chinese medicine (TCM) of the dried ripe fruit of Fructus Amomi (Sha Ren). A total of 38 compounds were identified by gas chromatography/mass spectrometry. Different SFE and SPME parameters (modifier content, extraction pressure, and temperature for SFE and fibers, extraction temperature, and time for SPME) were studied. The results by SFE and SPME were compared with those obtained by conventional SD and SE methods. The results showed that SFE and SPME are better sample preparation techniques than SD and SE. Due to SFE's requirement for expensive specialized instrumentation, the simplicity, low cost, and speed of SPME make it a more appropriate technique for extraction of volatile constituents in TCMs.     

Determination of volatile compounds in Magnolia bark by microwave-assisted extraction coupled to headspace solid-phase microextraction and gas chromatography-mass spectrometry.

A method is described for the determination of volatile compounds in Magnolia bark using microwave-assisted extraction coupled to headspace solid-phase microextraction (MAE-HS-SPME), followed by gas chromatography with mass spectrometry (GC-MS). Parameters affecting the extraction efficiency, such as sampling time and temperature, microwave irradiation power and desorption time, were investigated to achieve the optimal conditions. The result obtained was compared with that of steam distillation; only small differences existed between these two methods. Therefore, the proposed method seems to be a feasible and relatively simple, fast and solvent-free procedure for identification of essential oils in Magnolia bark.     

蛇油的挥发性成分分析和脱腥

采用水蒸汽蒸馏、黏土吸附、乙醇-乙酸乙酯共沸的方法除去蛇油的腥味,运用顶空固相微萃取(SPME)-气相色谱(GC)-质谱(MS)联用技术分析脱腥前后蛇油中挥发性成分的变化,并运用GC-MS联用技术分析脱腥后的蛇油中的脂肪酸.结果表明水蒸汽蒸馏是效果最佳的脱腥方法,它可使蛇油挥发性成分的量降至脱腥前的38%,使腥味的主要成分减少60%～100%,同时较大程度地保留了多不饱和脂肪酸.     

Solvent-free microwave extraction of essential oil from aromatic herbs: comparison with conventional hydro-distillation

Solvent-free microwave extraction (SFME) is a combination of microwave heating and dry distillation, performed at atmospheric pressure without added any solvent or water. Isolation and concentration of volatile compounds are performed by a single stage. SFME has been compared with a conventional technique, hydro-distillation (HD), for the extraction of essential oil from three aromatic herbs: basil (Ocimum basilicum L.), garden mint (Mentha crispa L.), and thyme (Thymus vulgaris L.). The essential oils extracted by SFME for 30min were quantitatively (yield) and qualitatively (aromatic profile) similar to those obtained by conventional hydro-distillation for 4.5 h. The SFME method yields an essential oil with higher amounts of more valuable oxygenated compounds, and allows substantial savings of costs, in terms of time, energy and plant material. SFME is a green technology and appears as a good alternative for the extraction of essential oils from aromatic plants.     

一种简易同时蒸馏萃取方法用于八角茴香挥发油提取及其GC-MS分析

设计了一种简易同时蒸馏萃取(SSDE)装置并用于八角茴香挥发油提取及其气相色谱-质谱法(GC-MS)分析。 该装置由圆底烧瓶、恒压滴液漏斗和回流冷凝管构成。 通过对八角茴香挥发油组分的GC-MS分析,比较SSDE法和水蒸汽蒸馏提取法(HD)提取植物源挥发油的效果。 结果表明,SSDE法所得挥发油相对含量在0.1%以上的19种化合物占挥发油总量的98.84%(相对标准偏差(RSD)(n=3)均不大于5.59%,其中RSD﹤5%的17种化合物占鉴定组分89.5%。SSDE法和HD法挥发油平均收率分别为7.30%(RSD=2.37%(n=5))和6.67%(RSD=5.26%(n=5))。 SSDE法简便、快速,适用于八角茴香挥发油的提取。     

独活挥发油化学成分的气相色谱-质谱法测定

采用水蒸气蒸馏法从独活中提取挥发油。采用不同类型的毛细管柱进行分析 ,找出最佳分析条件 ,共分离出50个峰 ,用归一化法测定其相对含量 ,并用气相色谱 -质谱法对化学成分进行鉴定 ,共鉴定了40个成分 ,占挥发油总成分的80 %以上。     

An improved microwave Clevenger apparatus for distillation of essential oils from orange peel

Microwave Clevenger or microwave accelerated distillation (MAD) is a combination of microwave heating and distillation, performed at atmospheric pressure without added any solvent or water. Isolation and concentration of volatile compounds are performed by a single stage. MAD extraction of orange essential oil was studied using fresh orange peel from Valencia late cultivar oranges as the raw material. MAD has been compared with a conventional technique, which used a Clevenger apparatus with hydro-distillation (HD). MAD and HD were compared in term of extraction time, yields, chemical composition and quality of the essential oil, efficiency and costs of the process. Extraction of essential oils from orange peels with MAD was better in terms of energy saving, extraction time (30 min versus 3 h), oxygenated fraction (11.7% versus 7.9%), product yield (0.42% versus 0.39%) and product quality. Orange peels treated by MAD and HD were observed by scanning electronic microscopy (SEM). Micrographs provide evidence of more rapid opening of essential oil glands treated by MAD, in contrast to conventional hydro-distillation.     

Comparison of different extraction methods: steam distillation, simultaneous distillation and extraction and headspace co-distillation, used for the analysis of the volatile components in aged flue-cured tobacco leaves

Steam distillation (SD), simultaneous distillation and extraction (SDE) and headspace co-distillation (HCD) were compared here for their effectiveness in the extraction of volatile compounds from tobacco. The different grades of aged flue-cured tobacco leaves extracted by the three methods respectively were analyzed using GC-MS. Mass spectra or authentic compounds were used to identify around 408 components in various volatile fractions. On the one hand, the qualitative comparison showed that more compounds were detected in HCD extract (391 components) than in SDE extract (377 components), and the approximately quantitative analysis showed that the total amount of volatile components in SDE extract (445.48 microg/g) was much more than that in HCD extract (315.72 microg/g). But on the other hand, HCD was the most efficient for nearly all the highly volatile compounds among the three methods. As to low-volatile compounds such as lactones, long chain aldehydes, ketones, alcohols, and esters, more was detected in SDE extract than in HCD extract. The SD method (322 components, total amount 228.42 microg/g) was the lowest sensitive to all compounds except semi-volatile fatty acids among the three methods.     

Rapid analysis of Achillea tenuifolia Lam essential oils by polythiophene/hexagonally ordered silica nanocomposite coating as a solid-phase microextraction fibre

In this work, a highly porous fibre coated with polythiophene/hexagonally ordered silica nanocomposite (PT/SBA-15) was prepared and used for extraction of essential oils with microwave-assisted distillation headspace solid phase microextraction (MA-HS-SPME) method. The prepared nanomaterials were immobilised on a stainless steel wire for fabrication of the SPME fibre. Using MA-HS-SPME followed by GC-MS, 24 compounds were separated and identified in Achillea tenuifolia, which mainly included limonene (28.6%), α-cadinol (12.7%), borneol (6.7%), caryophyllene oxide (3.2%), bornyl acetate (4.3%), camphene (3.2%) and para-cymene (2.3%). The experimental results showed that the polythiophene/hexagonally ordered silica nanocomposite fibres were suitable for the semi-quantitative study of the composition of essential oils in plant materials and for monitoring the variations in the volatile components of the plants.     

苦杏仁挥发油化学成分的微波-同时蒸馏萃取GC-MS分析

报道了用微波照射－同时蒸馏萃取法提取苦杏仁挥发性物质，测得苦杏仁挥发油的含量为4.5%（ω），利用GC－MS法分离确认出18种化学成分，用峰面积归一化法通过化学工作站数据处理系统得出各化学成分在挥发油中的相对含量；其中主要成分为苯甲醛，占总挥发油的89.1%；又用加成分解法分离出苯甲醛，并用IR、EI－MS法对其进行分析鉴定加以确认。     

Study of the Essential Oil Composition of Cumin Seeds by an Amino Ethyl-Functionalized Nanoporous SPME Fiber

An ultrasound assisted SPME method with a new nanoporous SBA-15 fiber functionalized with 3-[bis(2-hydroxyethyl)amino]propyl-triethoxysilane was successfully applied to the study of the essential oil composition of cumin (Cuminum cyminum L.) seeds. The sample was irradiated by ultrasound radiation and its volatile components were collected by the fiber from the sample headspace and directly injected into a GC-MS injection port for analysis. A simplex method was used for optimization of four different parameters affecting the efficiency of the extraction. Under the optimized conditions (i.e. sample weight, 0.6 g; temperature, 70 °C; sonication time, 12 min and extraction time, 28 min), the number of components identified by the proposed method and their amounts were identical to those of a hydrodistillation technique. The extraction efficiency of the SBA-15 fiber was superior to a PDMS commercial fiber. The major components identified were p-menta-1,3-dien-7-al, cuminaldehyde, γ-terpinene and p-cymene, respectively. The proposed method was applied to a comparative study of the essential oil composition of cumin in three different climate conditions of the Lorestan province in Iran. The results indicated that the essential oils in the temperate and tropical locations were 94.0 and 85.6% of the cold region, respectively.     

Separation and identification of volatile constituents in Artemisia argyi flowers by GC-MS with SPME and steam distillation

Artemisia argyi leaf is a widely used traditional Chinese medicine (TCM). In this work, for the first time, the separation and identification of volatile constituents in Artemisia argyi flowers is performed. Gas chromatography-mass spectrometry (GC-MS) with solid-phase microextraction (SPME) is developed for the fast analysis of volatile constituents in the flowers. Several headspace SPME parameters, including fiber coating, extraction temperature, and extraction time, are optimized. Forty-nine compounds in the flowers are re-identified by SPME-GC-MS. At the same time, in order to compare with the SPME, steam distillation is used for analysis of the volatile constituents in the flowers, and forty-seven are detected. The total fifty-three compounds in the flowers, which mainly include cylcofenchene, alpha-pinene, alpha-myrcene, D-limonene, caryophyllene, and germacrene D, are identified by the two methods. Compared to the volatile components in Artemisia argyi leaves, the main components (including the two active compounds of borneol and borneol acetate) are also found in Artemisia argyi flowers. These results show that Artemisia argyi flowers as well as leaves might be used as TCM.