Characterization of volatile substances in apples from Rosaceae family by headspace solid‐phase microextraction followed by GC‐qMS

The volatile composition of different apple varieties of Malus domestica Borkh. species from different geographic regions at Madeira Islands, namely Ponta do Pargo (PP), Porto Santo (PS), and Santo da Serra (SS) was established by headspace solid‐phase microextraction (HS‐SPME) procedure followed by GC‐MS (GC‐qMS) analysis. Significant parameters affecting sorption process such as fiber coating, extraction temperature, extraction time, sample amount, dilution factor, ionic strength, and desorption time, were optimized and discussed. The SPME fiber coated with 50/30 μm divinylbenzene/carboxen/PDMS (DVB/CAR/PDMS) afforded highest extraction efficiency of volatile compounds, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 50°C for 30 min with constant magnetic stirring. A qualitative and semi‐quantitative analysis between the investigated apple species has been established. It was possible to identify about 100 of volatile compounds among pulp (46, 45, and 39), peel (64, 60, and 64), and entire fruit (65, 43, and 50) in PP, PS, and SS apples, respectively. Ethyl esters, terpenes, and higher alcohols were found to be the most representative volatiles. α‐Farnesene, hexan‐1‐ol and hexyl 2‐methylbutyrate were the compounds found in the volatile profile of studied apples with the largest GC area, representing, on average, 24.71, 14.06, and 10.80% of the total volatile fraction from PP, PS, and SS apples. In PP entire apple, the most abundant compounds identified were α‐farnesene (30.49%), the unknown compound m/z (69, 101, 157) (21.82%) and hexyl acetate (6.57%). Regarding PS entire apple the major compounds were α‐farnesene (16.87%), estragole (15.43%), hexan‐1‐ol (10.94), and E‐2‐hexenal (10.67). α‐Farnesene (30.3%), hexan‐1‐ol (18.90%), 2‐methylbutanoic acid (4.7%), and pentan‐1‐ol (4.6%) were also found as SS entire apple volatiles present in a higher relative content. Principal component analysis (PCA) of the results clustered the apples into three groups according to geographic origin. Linear discriminant analysis (LDA) was performed in order to detect the volatile compounds able to differentiate the three kinds of apples investigated. The most important contributions to the differentiation of the PP, PS, and SS apples were ethyl hexanoate, hexyl 2‐methylbutyrate, E,E‐2,4‐heptadienal, p‐ethyl styrene, and E‐2‐hexenal.     

Polythiophene/hexagonally ordered silica nanocomposite coating as a solid‐phase microextraction fiber for the determination of polycyclic aromatic hydrocarbons in water

A highly porous fiber coated with polythiophene/hexagonally ordered silica nanocomposite was prepared for solid‐phase microextraction (SPME). The prepared nanomaterial was immobilized onto a stainless‐steel wire for the fabrication of the SPME fiber. Polythiophene/hexagonally ordered silica nanocomposite fibers were used for the extraction of some polycyclic aromatic hydrocarbons from water samples. The extracted analytes were transferred to the injection port of a gas chromatograph using a laboratory‐designed SPME device. The results obtained prove the ability of the polythiophene/hexagonally ordered silica material as a new fiber for the sampling of organic compounds from water samples. This behavior is due most probably to the increased surface area of the polythiophene/hexagonally ordered silica nanocomposite. A one‐at‐a‐time optimization strategy was applied for optimizing the important extraction parameters such as extraction temperature, extraction time, ionic strength, stirring rate, and desorption temperature and time. Under the optimum conditions, the LOD of the proposed method is 0.1–3 pg/mL for analysis of polycyclic aromatic hydrocarbons from aqueous samples, and the calibration graphs were linear in a concentration range of 0.001–20 ng/mL (R² > 0.990) for most of the polycyclic aromatic hydrocarbons. The single fiber repeatability and fiber‐to‐fiber reproducibility were less than 8.6 and 19.1% (n = 5), respectively.     

碳纳米管顶空固相微萃取测定水中的多溴联苯醚

建立了顶空固相微萃取联结气相色谱-电子捕获检测器（HS-SPME-GC-ECD）测定水中多溴联苯醚的方法。制作了多壁碳纳米管涂层固相微萃取探头。优化了萃取时间,萃取温度,搅拌速度,顶空体积,溶液的pH,离子强度及有机溶剂等影响萃取效率的各种因素。比较了室温和100 ℃顶空萃取和直接萃取的效率。结果表明,室温下直接萃取比顶空萃取的效率高2-4倍,而在100 ℃时顶空萃取比直接萃取的效率高1-8倍。除BDE-154外,无论直接萃取还是顶空萃取,100 ℃时的萃取效率均高于室温。方法的线性范围50-1600 ng/L,相关系数为0.995-0.998,5种多溴联苯醚的最低检出限（S/N=3）为1.14-16.25 ng/L,相对标准偏差（RSD%,n=5）小于10%。本方法用于真实水样的测定,回收率为74.2%-98.7%。     

Use of two different coating temperatures for a cold fiber headspace solid‐phase microextraction system to determine the volatile profile of Brazilian medicinal herbs

In this study, the experimental extraction conditions on applying headspace solid‐phase microextraction and cold fiber headspace solid‐phase microextraction (CF‐HS‐SPME) procedures to samples of six medicinal herbs commonly found in southern Brazil were optimized. The optimized conditions for headspace solid‐phase microextraction were found to be an extraction temperature of 60°C and extraction time of 40 min. For CF‐HS‐SPME, the corresponding values were 60°C and 15 min. In the case of the coating temperature for the CF‐HS‐SPME system, two approaches were investigated: (i) Temperature of 5°C applied during the whole extraction procedure; and (ii) the use of two fiber temperatures in the same extraction procedure with the aim of extracting the volatile and semivolatile compounds, the ideal condition being 60°C for the first 7.5 min and 5°C for the final 7.5 min. The three extraction procedures were compared. The CF‐HS‐SPME procedure had good performance only for the more volatile compounds whereas the strategy using two coating temperatures in the same procedure showed good performance for all compounds studied. It was also possible to determine the profile for the volatile fraction of each herb studied applying this technique followed by GC‐MS.     

Preparation of a New Solid‐Phase Microextraction Fiber by Coating Silylated Nanoporous Silica on a Copper Wire

LUS‐1 typed nanoporous silica particles were synthesized and silylated with hexamethyldisilazane and investigated as a highly porous fiber coating for solid‐phase microextraction (SPME). The pore size distribution of the prepared Sil‐LUS‐1 was still typical of MCM‐41 and centered at 3 nm with a specific surface area of 720 m²g^?1. The SPME fiber was prepared by liming the material on a copper wire. The extraction efficiency of the new fiber was compared with a commercial PDMS fiber for headspace extraction and GC‐MS analysis of phenol, 4‐nitrophenol, 2,4‐dichlorophenol and 4‐chlorophenol in water samples. Due to the high porosity of the prepared fiber it showed a higher sensitivity and better selectivity for the extraction of the target compounds. For optimization of different factors affecting the extraction efficiency, a simplex optimization method was used. The relative standard deviation for the measurements by one fiber was better than 7% for five replicates and the fiber‐to‐fiber reproducibility was about 10% for five fabricated fibers. Detection limits in the range of 0.002 to 0.026 μg mL^?1 were obtained for the phenolic compounds. The fiber was successfully applied for the determination of phenolic compounds in natural water samples.     

Speciation of inorganic and tetramethyltin by headspace solid‐phase microextraction and gas chromatography–mass spectrometry

A headspace solid‐phase microextraction (HS‐SPME) method coupled to GC‐MS was developed in order to determine trace levels of tetramethyltin (TeMT) and inorganic tin (iSn) after ethylation to tetraethyltin (TeET) in various matrices. The derivatization of iSn and the extraction of both TeMT and iSn as TeET were performed in one step. Sodium tetraethylborate (NaBEt₄) was used as derivatization agent and the volatile derivatives were absorbed on a PDMS‐coated fused silica fiber. The conditions for the HS‐SPME procedure were optimized in order to gain in repeatability and sensitivity. Several critical parameters of GC‐MS were also studied. The detection of TeMT and iSn as TeET peaks was performed by the SIM mode. The precision of the proposed method is satisfactory providing RSD values below 10% for both tin species and good linearity up to 10 μg/L. The developed method was successfully applied to the determination of tin species in several samples like canned fish, fish tissues, aquatic plants, canned mineral water and sea water. The proposed HS‐SPME‐GC‐MS method was proved suitable to monitor the concentration levels of toxic tin compounds in environmental and biological samples.     

A platinized stainless steel fiber with in‐situ coated polyaniline/polypyrrole/graphene oxide nanocomposite sorbent for headspace solid‐phase microextraction of aliphatic aldehydes in rice samples

The surface of a stainless steel fiber was made larger, porous and cohesive by platinizing for tight attachment of its coating. Then it was coated by a polyaniline/polypyrrole/graphene oxide (PANI/PP/GO) nanocomposite film using electrochemical polymerization. The prepared PANI/PP/GO fiber was used for headspace solid‐phase microextraction (HS‐SPME) of linear aliphatic aldehydes in rice samples followed by GC‐FID determination. To achieve the highest extraction efficiency, various experimental parameters including extraction time and temperature, matrix modifier and desorption condition were studied. The linear calibration curves were obtained over the range of 0.05–20 μg g⁻¹ (R ² > 0.99) for C₄–C₁₁ aldehydes. The limits of detection were found to be in the range of 0.01–0.04 μg g⁻¹. RSD values were calculated to be <7.4 and 10.7% for intra‐ and inter‐day, respectively. The superiority of the prepared nanocomposite SPME fiber was established by comparison of its results with those obtained by polydimethylsiloxane, carbowax–divinylbenzene, divinylbenzene–carboxen–polydimethylsiloxane and polyacrylate commercial ones. Finally, the nanocomposite fiber was used to extract and determine linear aliphatic aldehydes in 18 rice samples.     

Evaluation of needle trap micro‐extraction and solid‐phase micro‐extraction: Obtaining comprehensive information on volatile emissions from in vitro cultures

Volatile organic compounds (VOCs) emitted from in vitro cultures may reveal information on species and metabolism. Owing to low nmol L⁻¹ concentration ranges, pre‐concentration techniques are required for gas chromatography–mass spectrometry (GC–MS) based analyses. This study was intended to compare the efficiency of established micro‐extraction techniques – solid‐phase micro‐extraction (SPME) and needle‐trap micro‐extraction (NTME) – for the analysis of complex VOC patterns. For SPME, a 75 μm Carboxen®/polydimethylsiloxane fiber was used. The NTME needle was packed with divinylbenzene, Carbopack X and Carboxen 1000. The headspace was sampled bi‐directionally. Seventy‐two VOCs were calibrated by reference standard mixtures in the range of 0.041–62.24 nmol L⁻¹ by means of GC–MS. Both pre‐concentration methods were applied to profile VOCs from cultures of Mycobacterium avium ssp. paratuberculosis. Limits of detection ranged from 0.004 to 3.93 nmol L⁻¹ (median = 0.030 nmol L⁻¹) for NTME and from 0.001 to 5.684 nmol L⁻¹ (median = 0.043 nmol L⁻¹) for SPME. NTME showed advantages in assessing polar compounds such as alcohols. SPME showed advantages in reproducibility but disadvantages in sensitivity for N‐containing compounds. Micro‐extraction techniques such as SPME and NTME are well suited for trace VOC profiling over cultures if the limitations of each technique is taken into account.     

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.     

Comparative analysis of volatile constituents between recipe jingfangsan and its single herbs by GC‐MS combined with alternative moving window factor analysis method

Comparative analysis of volatile constituents between recipe jingfangsan and its single herbs was performed by GC‐MS combined with alternative moving window factor analysis (AMWFA), a new chemometric resolution method. Identification of the compounds was also assisted by comparison of temperature‐programmed retention indices (PTRIs) on the OV‐1 column with authentic samples. In total, 36, 29, and 42 volatile components in essential oil of Herba schizonepetae (HS), Radix saposhnikoviae (RS), and the recipe were respectively determined qualitatively and quantitatively, accounting for 81.80, 82.62 and 85.98% total contents of volatile oil of HS, RS, and the recipe respectively. Analysis by the method of AMWFA indicates that there are 22 common volatile constituents between the recipe and single herbal medicine HS, and 14 common volatile constituents between the recipe and single herb medicine RS. The experimental results also show that the volatile components of the recipe in number are almost addition of that of two single herbal medicines HS and RS, and are mainly from the single herbal medicine HS.     

Isolation of volatiles from Nigella sativa seeds using microwave‐assisted extraction: effect of whole extracts on canine and murine CYP1A

The volatile components of Nigella sativa seeds were isolated using microwave‐assisted extraction (MAE) and identified using gas chromatography. Further investigations were carried out to demonstrate the effects of whole extracts on canine (dog) and murine (rat) cytochrome P450 1A (CYP1A). The optimal extraction conditions of MAE were as follows: 25 mL of water, medium level of microwave oven power and 10 min of extraction time. A total of 32 compounds were identified under the conditions using GC‐FID and GC‐MS. Thymoquinone (38.23%), p‐cymene (28.61%), 4‐isopropyl‐9‐methoxy‐1‐methyl‐1‐cyclohexene (5.74%), longifolene (5.33%), α‐thujene (3.88) and carvacol (2.31%) were the main compounds emitted from N. sativa seeds. Various extracts including pure compounds, essential oil, nonpolar partition, relatively high‐polar/nonpolar partition, and polar partition extracts effectively inhibited the reaction of ethoxyresorufin O‐de‐ethylation, which is specified for CYP1A activity both in dog and rat. This in vitro data should be heeded as a signal of possible in vivo interactions. The use of human liver preparations would considerably strengthen the practical impact of the data generated from this study. Copyright © 2013 John Wiley & Sons, Ltd.     

Application of mesoporous carbon as a solid‐phase microextraction fiber coating for the extraction of volatile aromatic compounds

A mesoporous carbon was fabricated using MCM‐41 as a template and sucrose as a carbon source. The carbon material was coated on stainless‐steel wires by using the sol–gel technique. The prepared solid‐phase microextraction fiber was used for the extraction of five volatile aromatic compounds (chlorobenzene, ethylbenzene, o‐xylene, bromobenzene, and 4‐chlorotoluene) from tea beverage samples (red tea and green tea) prior to gas chromatography with mass spectrometric detection. The main experimental parameters affecting the extraction of the volatile aromatic compounds by the fiber, including the extraction time, sample volume, extraction temperature, salt addition, and desorption conditions, were investigated. The linearity was observed in the range from 0.1 to 10.0 μg/L with the correlation coefficients (r) ranging from 0.9923 to 0.9982 and the limits of detection were less than 10.0 ng/L. The recoveries of the volatile aromatic compounds by the method from tea beverage samples at spiking levels of 1.0 and 10.0 μg/L ranged from 73.1 to 99.1%.     

Graphene‐coated fiber for solid‐phase microextraction of triazine herbicides in water samples

Graphene is a novel and interesting carbon material that could be used for the separation and purification of some chemical compounds. In this investigation, graphene was used as a novel fiber‐coating material for the solid‐phase microextraction (SPME) of four triazine herbicides (atrazine, prometon, ametryn and prometryn) in water samples. The main parameters that affect the extraction and desorption efficiencies, such as the extraction time, stirring rate, salt addition, desorption solvent and desorption time, were investigated and optimized. The optimized SPME by graphene‐coated fiber coupled with high‐performance liquid chromatography‐diode array detection (HPLC‐DAD) was successfully applied for the determination of the four triazine herbicides in water samples. The linearity of the method was in the range from 0.5 to 200 ng/mL, with the correlation coefficients (r) ranging from 0.9989 to 0.9998. The limits of detection of the method were 0.05‐0.2 ng/mL. The relative standard deviations varied from 3.5 to 4.9% (n=5). The recoveries of the triazine herbicides from water samples at spiking levels of 20.0 and 50.0 ng/mL were in the range between 86.0 and 94.6%. Compared with two commercial fibers (CW/TPR, 50 μm; PDMS/DVB, 60 μm), the graphene‐coated fiber showed higher extraction efficiency.     

Application of a new fiber coating based on electrochemically reduced graphene oxide for the cold‐fiber headspace solid‐phase microextraction of tricyclic antidepressants

A new fiber based on the electrochemical reduction of graphene oxide was prepared on a copper wire for solid‐phase microextraction (SPME) applications. The prepared fiber was used for the SPME and gas chromatographic analysis of tricyclic antidepressants (TCADs), including amitriptyline, trimipramine, and clomipramine. The feasibility of direct‐immersion and headspace modes of SPME for the determination of TCADs was studied. The effects of four parameters including pH, salt content, extraction temperature with and without cooling the fiber, and extraction time were investigated. The comparison showed that headspace cold fiber SPME results in the best outcome for the extraction of TCADs. Under the optimized conditions of this mode, the calibration curves were linear between 2.0 and 500 ng/mL and the detection limits were between 0.30 and 0.53 ng/mL. The intraday and interday RSDs obtained at 20 ng/mL (n = 5), using a single fiber, were 5.5–9.0 and 7.5–9.8, respectively. The fiber to fiber repeatability (n = 4), expressed as the RSD, was between 12.8 and 13.2% at a 20 ng/mL concentration level. The method was successfully applied to the analysis of TCADs in plasma samples showing recoveries from 73 to 96%.     

QSRR Study of GC Retention Indices of Volatile Compounds Emitted from Mosla chinensis Maxim by Multiple Linear Regression

The volatile compounds emitted from Mosla chinensis Maxim were analyzed by headspace solid‐phase microextraction (HS‐SPME) and headspace liquid‐phase microextraction (HS‐LPME) combined with gas chromatography‐mass spectrometry (GC‐MS). The main volatiles from Mosla chinensis Maxim were studied in this paper. It can be seen that 61 compounds were separated and identified. Forty‐nine volatile compounds were identified by SPME method, mainly including myrcene, α‐terpinene, p‐cymene, (E)‐ocimene, thymol, thymol acetate and (E)‐β‐farnesene. Forty‐five major volatile compounds were identified by LPME method, including α‐thujene, α‐pinene, camphene, butanoic acid, 2‐methylpropyl ester, myrcene, butanoic acid, butyl ester, α‐terpinene, p‐cymene, (E)‐ocimene, butane, 1,1‐dibutoxy‐, thymol, thymol acetate and (E)‐β‐farnesene. After analyzing the volatile compounds, multiple linear regression (MLR) method was used for building the regression model. Then the quantitative structure‐retention relationship (QSRR) model was validated by predictive‐ability test. The prediction results were in good agreement with the experimental values. The results demonstrated that headspace SPME‐GC‐MS and LPME‐GC‐MS are the simple, rapid and easy sample enrichment technique suitable for analysis of volatile compounds. This investigation provided an effective method for predicting the retention indices of new compounds even in the absence of the standard candidates.     

A Microwave‐assisted Headspace Solid‐phase Microextraction for Rapid Determination of Synthetic Polycyclic and Nitro‐aromatic Musks in Fish Samples

Rapid solvent‐free microwave‐assisted headspace solid‐phase microextraction (MA‐HS‐SPME) coupled with gas chromatography‐mass spectrometry (GC‐MS) was developed to determine synthetic polycyclic and nitro‐aromatic musks in fish samples. Four commonly used synthetic musks, galaxolide (HHCB), tonalide (AHTN), musk xylene (MX) and musk ketone (MK) were employed in the method development and validation. The parameters (microwave irradiation time, irradiation power, amount of water addition, pH value and addition of NaCl) affecting the extraction efficiency of analytes from fish slurry were systematically investigated and optimized. The best extraction conditions were achieved when the fish sample 2‐g mixed with 4‐mL methanol and 15‐mL deionized water (containing 4 g of NaCl, pH 2.0 in a 40‐mL sample‐vial) was microwave irradiated at 80 watt for 5 min. The limits of quantification (LOQ) were 0.4 to 1.2 ng/g in 2‐g of wet tissue. The precision for these analytes, as indicated by relative standard deviations, were less than 9% for both intra‐ and inter‐day analysis. Accuracy, expressed as the mean extraction recovery, was between 80 to 92%. A standard addition method was used to quantitate these four synthetic musks, and the total concentrations ranged from 2.1 to 23.1 ng/g in various fish samples.     

Selective determination of alkylmercury compounds in solid matrices after subcritical water extraction,followed by solid‐phase microextraction and GC–MS

A method for the extraction and determination of methylmercury (MeHg) in solid matrices is presented. Combining the advantages of two extraction techniques—subcritical water extraction (subWE) and solid‐phase microextraction (SPME)—selective separation of MeHg from soils is possible. The procedure is based on extraction with subcritical water without using organic solvents, followed by in situ aqueous‐phase derivatization with sodium tetraethylborate and headspace SPME with a silica fiber coated with poly(dimethylsiloxane). The optimization of the extraction parameters is described. The identification and quantification of the extracted alkylmercury compounds from spiked soil samples is performed by GC–MS after thermal desorption. Copyright © 2000 John Wiley & Sons, Ltd.     

Microwave‐assisted extraction coupled with countercurrent chromatography for the rapid preparation of flavonoids from Scutellaria barbata D. Don

As a famous Chinese herb having good inhibitory effects on numerous human cancers both in vitro and in vivo, Scutellaria barbata D. Don attracts extensive attention worldwide. In this work, four flavonoids named scutellarin, baicalin, luteolin, and apigenin were simply and rapidly prepared from S. barbata by microwave‐assisted extraction coupled to countercurrent chromatography. Extraction conditions including irradiation time, extraction temperature, liquid/solid ratio, and microwave power were optimized using an orthogonal array design method. The extract of S. barbata was separated and purified with a two‐phase solvent system composed of hexane/ethyl acetate/methanol/acetic acid/water (1:5:1.5:1:4, v/v/v/v/v) and 4.5 mg of scutellarin, 4.6 mg of baicalin, 1.1 mg of luteolin, 2.1 mg of apigenin were obtained from 2.0 g original sample in a single run. The purities of scutellarin, baicalin, luteolin, and apigenin determined by HPLC were 93.6, 97.3, 97.6, and 98.4%, respectively. The targeted compounds were identified by LC with MS and ¹H NMR spectroscopy. The total time including extraction, separation, and purification was <300 min. Compared to traditional methods, microwave‐assisted extraction coupled to countercurrent chromatography method is more simple and rapid for the extraction, separation, and purification of flavonoid compounds from natural products.     

Rapid preparative separation of six bioactive compounds from Gentiana crassicaulis Duthie ex Burk. using microwave‐assisted extraction coupled with high‐speed counter‐current chromatography

A rapid method combining microwave‐assisted extraction (MAE) and high‐speed counter‐current chromatography (HSCCC) was applied for preparative separation of six bioactive compounds including loganic acid ( I ), isoorientin‐4′‐O‐glucoside ( II ), 6′‐O‐β‐d ‐glucopyranosyl gentiopicroside ( III ), swertiamarin ( IV ), gentiopicroside ( V ), sweroside ( VI ) from traditional Tibetan medicine Gentiana crassicaulis Duthie ex Burk. MAE parameters were predicted by central composite design response surface methodology. That is, 5.0 g dried roots of G. crassicaulis were extracted with 50 mL 57.5% aqueous ethanol under 630 W for 3.39 min. The extract (gentian total glycosides) was separated by HSCCC with n‐butanol/ethyl acetate/methanol/1% acetic acid water (7.5:0.5:0.5:3.5, v/v/v/v) using upper phase mobile in tail‐to‐head elution mode. 16.3, 8.8, 12., 25.1, 40.7, and 21.8 mg of compounds I–VI were obtained with high purities in one run from 500 mg of original sample. The purities and identities of separated components were confirmed using HPLC with photo diode array detection and quadrupole TOF‐MS and NMR spectroscopy. The study reveals that response surface methodology is convenient and highly predictive for optimizing extraction process, MAE coupled with HSCCC could be an expeditious method for extraction and separation of phytochemicals from ethnomedicine.     

Ultra‐rapid non‐equilibrium solid‐phase microextraction at elevated temperatures and direct coupling to mass spectrometry for the analysis of lidocaine in urine

Solid‐phase microextraction (SPME) has been directly coupled to an ion‐trap mass spectrometer (MS) for the determination of the model compound lidocaine in urine, hereby applying MS/MS [fragmentation of [M + H]⁺ (m/z 235) to a fragment with m/z 86]. The throughput of samples has been increased using non‐equilibrium SPME with polydimethylsiloxane (PDMS) fibers. The effect of temperature on the sorption and the desorption was studied. Elevated temperatures during sorption (65°C) and desorption (55°C) had a considerable influence on the speed of the extraction. The desorption was carried out with a home‐made desorption chamber allowing thermostating. Only 1 min sorption and 1 min desorption were performed, after which MS detection took place, resulting in a total analysis time of 3 min. Detection limits below 1 ng/mL could be obtained despite yields of only 2.1 and 1.5% for a 100‐ and a 30‐μm PDMS‐coated fiber, respectively. Furthermore, the determination of lidocaine in urine had acceptable reproducibilities, i.e., relative standard deviations (RSDs) below 10%. A limit of quantitation (RSD < 15%) of about 1 ng/mL was obtained. No extra wash step of the extraction fiber was required after desorption if a 30‐μm coating was used, whereas not all the analyte was desorbed from the 100‐μm coating in a single desorption. Therefore, the SPME‐MS/MS system with a 30‐μm PDMS‐coated fiber for rapid non‐equilibrium SPME at elevated temperatures has interesting potential for high‐throughput analysis of biological samples.