Differentiation of essential oils in Atractylodes lancea and Atractylodes koreana by gas chromatography with mass spectrometry

Atractylodes rhizome is a valuable traditional Chinese medicinal herb that comprises complex several species whose essential oils are the primary pharmacologically active component. Essential oils of Atractylodes lancea and Atractylodes koreana were extracted by hydrodistillation, and the yield was determined. The average yield of essential oil obtained from A. lancea (2.91%) was higher than that from A. koreana (2.42%). The volatile components of the essential oils were then identified by a gas chromatography with mass spectrometry method that demonstrated good precision. The method showed clear differences in the numbers and contents of volatile components between the two species. 41 and 45 volatile components were identified in A. lancea and A. koreana, respectively. Atractylon (48.68%) was the primary volatile component in A. lancea, while eudesma‐4(14)‐en‐11‐ol (11.81%) was major in A. koreana. However, the most significant difference between A. lancea and A. koreana was the major component of atractylon and atractydin. Principal component analysis was utilized to reveal the correlation between volatile components and species, and the analysis was used to successfully discriminate between A. lancea and A. koreana samples. These results suggest that different species of Atractylodes rhizome may yield essential oils that differ significantly in content and composition.     

Direct analysis of alkaloid profiling in plant tissue by using matrix-assisted laser desorption/ionization mass spectrometry

A method for the direct determination of alkaloid profiling in plant tissues by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was developed. The alkaloid profiles of the herbs were obtained without the need for complicated sample preparation. Experimental results demonstrated that the direct MALDI-TOFMS analysis allowed rapid and reliable characterization of the components in plant tissues. Four commonly used Chinese medicinal herbs were studied, including Aconitum Carmichaeli Debx. (Fuzi in Chinese) and Processed Fuzi, for herb differentiation and explanation of the significant difference in their toxicities. The direct analysis method proved valuable for the preliminary study of plant component profiles. The rapid collection of information from the direct analysis on plant tissues could be valuable for supporting the discovery of new compounds and for the quality control of medicinal herbs.     

Fabrication of polyaniline‐coated halloysite nanotubes by in situ chemical polymerization as a solid‐phase microextraction coating for the analysis of volatile organic compounds in aqueous solutions

We have synthesized an organic–inorganic polyaniline–halloysite nanotube composite by an in situ polymerization method. This nanocomposite is immobilized on a stainless‐steel wire and can be used as a fiber coating for solid‐phase microextraction. It was found that our new solid‐phase microextraction fiber is an excellent adsorbent for the extraction of some volatile organic compounds in aqueous samples in combination with gas chromatography and mass spectrometry. The coating can be prepared easily, is mechanically stable, and exhibits relatively high thermal stability. It is capable of extracting phenolic compounds from water samples. Following thermal desorption, the phenols were quantified by gas chromatography with mass spectrometry. The effects of extraction temperature, extraction time, sample ionic strength, stirring rate, pH, desorption temperature and desorption time were studied. Under optimal conditions, the repeatability for one fiber (n = 5), expressed as the relative standard deviation, is between 6.2 and 9.1%. The detection limits range from 0.005 to 4 ng/mL. The method offers the advantage of being simple to use, with a shorter analysis time, lower cost of equipment and higher thermal stability of the fiber in comparison to conventional methods of analysis.     

Chemometrics comparison of gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry Daphnia magna metabolic profiles exposed to salinity

The performances of gas chromatography with mass spectrometry and of comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry are examined through the comparison of Daphnia magna metabolic profiles. Gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with mass spectrometry were used to compare the concentration changes of metabolites under saline conditions. In this regard, a chemometric strategy based on wavelet compression and multivariate curve resolution–alternating least squares is used to compare the performances of gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry for the untargeted metabolic profiling of Daphnia magna in control and salinity‐exposed samples. Examination of the results confirmed the outperformance of comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry over gas chromatography with mass spectrometry for the detection of metabolites in D. magna samples. The peak areas of multivariate curve resolution–alternating least squares resolved elution profiles in every sample analyzed by comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry were arranged in a new data matrix that was then modeled by partial least squares discriminant analysis. The control and salt‐exposed daphnids samples were discriminated and the most relevant metabolites were estimated using variable importance in projection and selectivity ratio values. Salinity de‐regulated 18 metabolites from metabolic pathways involved in protein translation, transmembrane cell transport, carbon metabolism, secondary metabolism, glycolysis, and osmoregulation.     

Comparative analysis of main bio‐active components in the herb pair Danshen‐Honghua and its single herbs by ultra‐high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry

A sensitive, reliable, and powerful ultra‐high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry method was developed for simultaneous quantification of the 15 main bio‐active components including phenolic acids and flavonoids within 13 min for the first time. The proposed method was first reported and validated by good linearity (r ² > 0.9975), limit of detection (1.12–7.01 ng/mL), limit of quantification (3.73–23.37 ng/mL), intra‐ and inter‐day precisions (RSD ≤ 1.92%, RSD ≤ 2.45%), stability (RSD ≤ 5.63%), repeatability (RSD ≤ 4.34%), recovery (96.84–102.12%), and matrix effects (0.92–1.02). The established analytical methodology was successfully applied to comparative analysis of main bio‐active components in the herb pair Danshen‐Honghua and its single herbs. Compared to the single herb, the content of most flavonoid glycosides was remarkably increased in their herb pair, and main phenolic acids were decreased, conversely. The content changes of the main components in the herb pair supported the synergistic effects on promoting blood circulation and removing blood stasis. The results provide a scientific basis and reference for the quality control of Danshen‐Honghua herb pair and the drug interactions based on variation of bio‐active components in herb pairs.     

Capillary chromatographic analysis of volatile organic compounds in the indoor environment

The wide variety of volatile organic compounds found in the indoor environment can present a difficult chromatographic problem for the analyst. Capillary-column gas chromatography is required to achieve adequate separation. Thermal desorption/capillary gas chromatography/mass spectrometry is usually the preferred method for broad spectrum analysis of the volatile organics detected indoors. Cryogenic trapping is required for capillary gas chromatographic analysis of the more volatile components.     

Head-space solid phase microextraction for the GC-MS analysis of terpenoids in herb based formulations

Head-Space Solid Phase Microextraction (HS-SPME) has been employed for sampling of volatile components and their volatile decomposition products occurring in herbal medicines and herb extracts with subsequent injection into a gas chromatographic column. The identification and quantification was performed by coupled gas chromatography – mass spectrometry (GC-MS) with classical splitless injection, electron impact ionization and a quadrupole mass analyzer. As fast and inexpensive technique for the isolation of organic analytes HS-SPME with GC-MS can be successfully employed for the quality control of herbal medicines and other formulations containing herb extracts. Analytical results with satisfying accuracy and precision are given.     

Quantitative and fingerprinting analysis of Atractylodes rhizome based on gas chromatography with flame ionization detection combined with chemometrics

This study assessed the feasibility of gas chromatography with flame ionization detection fingerprinting combined with chemometrics for quality analysis of Atractylodes rhizome. We extracted essential oils from 20 Atractylodes lancea and Atractylodes koreana samples by hydrodistillation. The variation in extraction yields (1.33–4.06%) suggested that contents of the essential oils differed between species. The volatile components (atractylon, atractydin, and atractylenolide I, II, and III) were quantified by gas chromatography with flame ionization detection and confirmed by gas chromatography with mass spectrometry, and the results demonstrated that the number and content of volatile components differed between A. lancea and A. koreana. We then calculated the relative peak areas of common components and similarities of samples by comparing the chromatograms of A. lancea and A. koreana extracts. Also, we employed several chemometric techniques, including similarity analysis, hierarchical clustering analysis, principal component analysis, and partial least‐squares discriminate analysis, to analyze the samples. Results were consistent across analytical methods and showed that samples could be separated according to species. Five volatile components in the essential oils were quantified to further validate the results of the multivariate statistical analysis. The method is simple, stable, accurate, and reproducible. Our results provide a foundation for quality control analysis of A. lancea and A. koreana.     

Rapid Extraction of Volatile Compounds Using a New Simultaneous Microwave Distillation: Solvent Extraction Device

Simultaneous distillation–extraction (SDE) is routinely used by analysts for sample preparation prior to gas chromatography analysis. In this work, a new process design and operation for microwave assisted simultaneous distillation–solvent extraction (MW-SDE) of volatile compounds was developed. Using the proposed method, isolation, extraction and concentration of volatile compounds can be carried out in a single step. To demonstrate its feasibility, MW-SDE was compared with the conventional technique, SDE, for gas chromatography-mass spectrometry (GC-MS) analysis of volatile compounds in a fresh aromatic herb, Zygophyllum album L., a wild salty desert herb belonging to the family Zygophyllaceae. SDE method required a long time (3 h) to isolate the volatile compounds, and large amounts of organic solvent (200 mL of hexane) for further extraction, while MW-SDE needed shorter time (only 30 min) to prepare the sample, and less amount of organic solvent (10 mL of hexane). These results show that MW-SDE–GC-MS is a simple, rapid and solvent-less method for the determination of volatile compounds from aromatic plants.     

Low‐temperature headspace‐trap gas chromatography with mass spectrometry for the determination of trace volatile compounds from the fruit of Lycium barbarum L.

The total saccharides content of Lycium barbarum L. is very high, and a high temperature would result in saccharide decomposition and the emergence of a large amount of water. Moreover, the volatile compounds from the fruit of L. barbarum L. are rather low in concentration. Hence, it is difficult for a conventional headspace method to study the volatile compounds from the fruit of L. barbarum L. Since headspace‐trap gas chromatography with mass spectrometry is an excellent method for trace analysis, a headspace‐trap gas chromatography with mass spectrometry method based on low‐temperature (30°C) enrichment and multiple headspace extraction was developed to explore the volatile compounds from the fruit of L. barbarum L. The headspace of the sample was extracted in 17 cycles at 30°C. Each time, the compounds extracted were concentrated in the trap (Tenax TA and Tenax GR, 1:1). Finally, all the volatile compounds were delivered into the gas chromatograph after thermal desorption. With the method described above, a total of 57 compounds were identified. The identification was completed by mass spectral search, retention index, and accurate mass measurement.     

An efficient biosorption‐based dispersive liquid‐liquid microextraction with extractant removal by magnetic nanoparticles for quantification of bisphenol A in water samples by gas chromatography‐mass spectrometry detection

In this work, a simple, fast, sensitive, and environmentally friendly method was developed for preconcentration and quantitative measurement of bisphenol A in water samples using gas chromatography with mass spectrometry. The preconcentration approach, namely biosorption‐based dispersive liquid‐liquid microextraction with extractant removal by magnetic nanoparticles was performed based on the formation of microdroplet of rhamnolipid biosurfactant throughout the aqueous samples, which accelerates the mass transfer process between the extraction solvent and sample solution. The process is then followed by the application of magnetic nanoparticles for easy retrieval of the analyte‐containing extraction solvent. Several important variables were optimized comprehensively including type of disperser solvent and desorption solvent, rhamnolipid concentration, volume of disperser solvent, amount of magnetic nanoparticles, extraction time, desorption time, ionic strength, and sample pH. Under the optimized microextraction and gas chromatography with mass spectrometry conditions, the method demonstrated good linearity over the range of 0.5–500 µg/L with a coefficient of determination of R² = 0.9904, low limit of detection (0.15 µg/L) and limit of quantification (0.50 µg/L) of bisphenol A, good analyte recoveries (84–120%) and acceptable relative standard deviation (1.8–14.9%, n = 6). The proposed method was successfully applied to three environmental water samples, and bisphenol A was detected in all samples.     

Chemical fingerprinting of Gardenia jasminoides fruit using direct sample introduction and gas chromatography with mass spectrometry detection

A rapid, rugged, and inexpensive approach is described to develop chemical fingerprints of volatile and semivolatile fractions in herbal medicine. The method is based on the combination of direct sample introduction and gas chromatography (GC) analysis with mass spectrometry detection. In comparison with routine methods, the proposed approach provides the most informative fingerprint and does not demand time-consuming extraction, pretreatment, and cleanup procedures. The approach was applied to establish the GC fingerprint of gardenia fruit (Gardenia jasminoides Ellis), in which 39 components were identified. With the help of principal components analysis, the obtained fingerprint could reveal the variation in and within different herb samples as affected by season and developmental state (wild or cultivated). The results indicated that the proposed approach could serve as a rapid, simple, and effective technique for the quality control of herbal medicines.     

Comparison of Headspace SPME with Hydrodistillation and SFE for Analysis of the Volatile Components of the Roots of Valeriana officinalis var. latifolia

Valeriana officinalis var. latifolia is a common medicinal and fragrant plant in China. The plant’s essential oil plays an important role in its sedative and hypnotic action. In this work, supercritical fluid extraction and headspace solid phase micro-extraction, with gas chromatography–mass spectrometry, were used for analysis of the volatile components of the roots of V. officinalis var. latifolia. The results were compared with those obtained by hydrodistillation. Seventy-two compounds were isolated and identified by GC–MS. The results showed that the major volatile components of V. officinalis var. latifolia were significantly different from those of V. officinalis, and varied with different extraction methods. SFE co-extracted high-molecular-weight compounds that do not contribute to the aroma. Hydrodistillation extraction resulted in loss of some highly volatile fragrant components. The conditions (extraction temperature and pressure) used for SFE affected the extraction yield and the composition of the oil.     

Rapid and green determination of 58 fragrance allergens in plush toys

This paper presents a simple, rapid, and green method based on a static headspace gas chromatography–mass spectrometry for determining 58 fragrance allergens in plush toys. This study is the first to meet the requirement for simultaneously determining 66 fragrances, except for eight natural extracts restricted by the European Toy Safety Directive 2009/48/EC. A minimal amount of sample (20 mg) and acetone solvent (20 μL) were placed in a headspace vial. A gas–solid equilibration of fragrances between the headspace and the sample was achieved within 10 min under the vapor atmosphere of acetone at 200°C, which allowed the fragrances in the sample to be measured by gas chromatography–mass spectrometry. Results showed that the interference caused by different sample matrices was negligible. The proposed method exhibited determination results that were highly similar to those of traditional ultrasonic extraction with sufficient sensitivity (limits of quantification: 0.02–10 mg/kg) for 58 fragrances, indicating its accuracy and reliability. The average recoveries ranged from 71.3 to 137.4%, and the relative standard deviation (n = 6) varied from 1.1 to 18.0%. Finally, the method was applied to monitor the fragrances in 20 commercial toys. This study provides a good reference for rapidly and greenly determining the semi‐volatile analytes in toys, textiles, and other products.     

Analysis of Artemisia annua L. volatile oil by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry

Artemisia annua L. is an annual herb native of Asia, it has been used for many centuries for the treatment of fever and malaria. In this paper, analysis of the volatile oil of Artemisia annua L. was performed by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GC-TOF MS). Three hundred and three components were tentatively identified and terpene compounds are the main components of Artemisia annua L. volatile oil. Artemisinic acid is tentatively qualified.     

Enhanced resolution of Mentha piperita volatile fraction using a novel medium‐polarity ionic liquid gas chromatography stationary phase

The evaluation of a novel medium‐polarity ionic‐liquid‐based gas chromatography column, SLB‐IL60, towards the analysis of a complex essential oil, namely, a peppermint essential oil sample, is reported. The SLB‐IL60 30 m column was subjected to bleeding measurements, by means of conventional gas chromatography with mass spectrometry. The SLB‐IL60 column was then evaluated in the analysis of pure standard compounds, chosen as typical constituents of peppermint essential oil. Resolution and peak symmetry (expressed as tailing factors at 10% of peak height) were measured and the results were compared to those obtained on the most widely used columns in such an application, namely a medium‐polarity [100% poly(ethyleneglycol)] stationary phase, and an apolar 5% diphenyl/95% dimethyl siloxane. The final part of the evaluation was dedicated to the gas chromatography with mass spectrometry analysis of a peppermint essential oil sample and again the data were compared to those obtained on the 100% poly(ethyleneglycol) and the 5% diphenyl/95% dimethyl siloxane phase. Linear retention indices were determined for all the identified components on the ionic liquid capillary.     

Fast analysis of glycosides based on HKUST‐1‐coated monolith solid‐phase microextraction and direct analysis in real‐time mass spectrometry

Glycosides are a kind of highly important natural aromatic precursors in tobacco leaves. In this study, a novel HKUST‐1‐coated monolith dip‐it sampler was designed for the fast and sensitive analysis of trace glycosides using direct analysis in real‐time mass spectrometry. This device was prepared in two steps: in situ polymerization of monolith in a glass capillary of dip‐it and layer‐by‐layer growth of HKUST‐1 on the surface of monolith. Sufficient extraction was realized by immersing the tip to solution and in situ desorption was carried out by plasma direct analysis in real time. Compared with traditional solid‐phase microextraction protocols, sample desorption was not needed anymore, and only extraction conditions were needed to be optimized in this method, including the gas temperature of direct analysis in real time, extraction time, and CH₃COONH₄ additive concentration. This method enabled the simultaneous detection of six kinds of glycosides with the limits of detection of 0.02–0.05 μg/mL and the linear ranges covering two orders of magnitude with the limits of quantitation of 0.05–0.1 μg/mL. Moreover, the developed method was applied for the glycosides analysis of three tobacco samples, which only took about 2 s for every sample.     

Advanced mono‐ and multi‐dimensional gas chromatography–mass spectrometry techniques for oxygen‐containing compound characterization in biomass and biofuel samples

A wide variety of biomass, from triglycerides to lignocellulosic‐based feedstock, are among promising candidates to possibly fulfill requirements as a substitute for crude oils as primary sources of chemical energy feedstock. During the feedstock processing carried out to increase the H:C ratio of the products, heteroatom‐containing compounds can promote corrosion, thus limiting and/or deactivating catalytic processes needed to transform the biomass into fuel. The use of advanced gas chromatography techniques, in particular multi‐dimensional gas chromatography, both heart‐cutting and comprehensive coupled to mass spectrometry, has been widely exploited in the field of petroleomics over the past 30 years and has also been successfully applied to the characterization of volatile and semi‐volatile compounds during the processing of biomass feedstock. This review intends to describe advanced gas chromatography–mass spectrometry‐based techniques, mainly focusing in the period 2011–early 2020. Particular emphasis has been devoted to the multi‐dimensional gas chromatography–mass spectrometry techniques, for the isolation and characterization of the oxygen‐containing compounds in biomass feedstock. Within this context, the most recent advances to sample preparation, derivatization, as well as gas chromatography instrumentation, mass spectrometry ionization, identification, and data handling in the biomass industry, are described.     

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.