Inter-specific variation in headspace scent volatiles composition of four commercially cultivated jasmine flowers

Jasmines are commercially grown for their fragrant flowers and essential oil production. The flowers of jasmine emit sweet-smelling fragrance from evening till midnight. This study was designed to study the composition and inter-specific variation of the emitted scent volatiles from flowers of four commercially cultivated Jasminum species namely, Jasminum sambac, Jasminum auriculatum, Jasminum grandiflorum and Jasminum multiflorum. Gas chromatography-mass spectrometry analysis revealed that the scent volatiles composition of these flowers was predominantly enriched with both terpenoid and benzenoid compounds. Linalool and (3E,6E)-α-farnesene were identified as the major monoterpene and sesquiterpene in all the four species, respectively. The most abundant benzenoid detected in all flowers was benzyl acetate. Comparison of volatile profiles indicated a variation in fragrance contents and types emitted from these four jasmine flowers. The outcome of this study shall help in elucidating the enzymes and genes of fragrance biosynthesis in jasmines and in aiming to create flowers with improved scent quality.     

Headspace Volatiles and Endogenous Extracts of Prunus mume Cultivars with Different Aroma Types

Prunus mume is a traditional ornamental plant, which owed a unique floral scent. However, the diversity of the floral scent in P. mume cultivars with different aroma types was not identified. In this study, the floral scent of eight P. mume cultivars was studied using headspace solid-phase microextraction (HS-SPME) and organic solvent extraction (OSE), combined with gas chromatography-mass spectrometry (GC-MS). In total, 66 headspace volatiles and 74 endogenous extracts were putatively identified, of which phenylpropanoids/benzenoids were the main volatile organic compounds categories. As a result of GC-MS analysis, benzyl acetate (1.55–61.26%), eugenol (0.87–6.03%), benzaldehyde (5.34–46.46%), benzyl alcohol (5.13–57.13%), chavicol (0–5.46%), and cinnamyl alcohol (0–6.49%) were considered to be the main components in most varieties. However, the volatilization rate of these main components was different. Based on the variable importance in projection (VIP) values in the orthogonal partial least-squares discriminate analysis (OPLS-DA), differential components of four aroma types were identified as biomarkers, and 10 volatile and 12 endogenous biomarkers were screened out, respectively. The odor activity value (OAV) revealed that several biomarkers, including (Z)-2-hexen-1-ol, pentyl acetate, (E)-cinnamaldehyde, methyl salicylate, cinnamyl alcohol, and benzoyl cyanide, contributed greatly to the strong-scented, fresh-scented, sweet-scented, and light-scented types of P. mume cultivars. This study provided a theoretical basis for the floral scent evaluation and breeding of P. mume cultivars.     

Floral scent composition of Plumeria tuberculata analyzed by HS-SPME

The headspace volatile compounds of the flowers of Plumeria tuberculata Lodd. were analyzed by solid phase microextraction coupled with capillary gas chromatography/mass spectrometry. Twenty-five compounds were identified, representing 100% of the total composition. The volatile fraction was characterized by oxygenated monoterpenes (79.6%), oxygenated sesquiterpenes (8.4%), sesquiterpene hydrocarbons (7.6%), and benzenoid esters (2.6%). The major components were geraniol (34.9%), citronelol (21.5%) and geranial (16.2%), and they were found to make the major contribution to the typical scent of this flower.     

Resonance structure counts in parallelogram-like benzenoids with holes

If a hexacyclic graph G represents a benzenoid, a perfect matching corresponds to a configuration of π-bonds. We present an algorithm for counting the number of configurations of π-bonds for parallelogram-like benzenoids with parallelogram-like holes by counting descending paths in a corresponding rectangular mesh with rectangular holes.     

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.     

Use of solid-phase microextraction as a sampling technique for the characterization of volatile compounds emitted from Chinese daffodil flowers

Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) has been applied to the determination of volatile compounds emitted from living daffodil flowers. The SPME conditions were optimized and applied to headspace extraction of the volatile compounds. The volatile compounds adsorbed on the fiber were desorbed and analyzed by GC-MS. We identified 27 compounds in the flower emission, which mainly included acetic acid phenethyl ester (31.68%), E-ocimene (17.15%), acetic acid benzyl ester (11.53%), neo-allo-ocimene (6.94%), allo-ocimene(5.34%), α-linalool (5.26%), 1,8-cineole(3.70%), benzenepropyl acetate (1.98%), and 3-methyl-2-buten-1-ol acetate(1.88%). The volatile compounds emitted by the flower excised from the daffodil were also analyzed by the present method, and the results showed that n-pentadecane, n-hexadecane, n-octadecane, and acetic acid phenethyl ester might be biomarker compounds of living daffodil flowers. To our knowledge, this is the first report on the volatile compounds emitted from Chinese daffodil flowers. The text was submitted by the authors in English.     

Analysis of volatile compounds in Herba Asari by single-drop micro-extraction gas chromatography mass spectrometry

A rapid headspace single-drop micro-extraction(mix) gas chromatography mass spectrometry(SDMEGC -MS) for the analysis of the volatile compounds in Herba Asari was developed in this study.A mixed solvent of n-tridecane and butyl acetate(1:1) was finally used for the extraction at 70 C for 15 min with sample amount of 0.750 g and 100 mesh particle size.Under the determined conditions,the pound samples of Herba Asari were directly applied for the analysis.SDME-GC-MS,SPME-GC-MS and SD-GCMS methods were compared and the results showed that SDME-GC-MS method was a simple, inexpensive and effective way to measure the volatile compounds in Herba Asari and could be used for the analysis of volatile compounds in complex samples.     

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.     

应用动态顶空吸附-气相色谱-质谱法分析算盘子花气味的化学成分

花气味在维持大戟科(Phyllanthaceae)算盘子属(Glochidion)植物和头细蛾(Epicephala)专性传粉互利共生体系中发挥关键作用。本研究采用动态顶空吸附法(dynamic headspace adsorption)收集算盘子(Glochidion puberum)花气味,运用气相色谱-质谱(GC-MS)联用技术分离并鉴定其化学成分,用峰面积归一化法测得各组分的相对含量。结果表明:算盘子花气味中共鉴定出45种挥发物,主要包含单萜和倍半萜类物质;芳樟醇(38.06%)和β-榄香烯(23.84%)相对含量最高,占总相对含量的61.9%,为主要的气味成分,推测这两种物质可能是吸引传粉头细蛾的重要气味成分。本研究为进一步开展触角电生理检测和生物行为试验来筛选吸引传粉头细蛾的活性物质提供了理论依据。     

Analysis of Volatile Organic Compounds from Dendranthema indicum var. aromaticum by Headspace Gas Chromatography-Mass Spectrometry and Accurate Mass Measurement

The volatile organic compounds from flowers, leaves, and stems of Dendranthema indicum var. aromaticum, obtained through a static headspace technique, were analyzed by gas chromatography-mass spectrometry (GC-MS) and accurate mass measurement. The qualitative approach, comprising accurate mass measurement, retention index, and mass spectral search, was utilized to identify compounds. A total of 162 components were identified, representing 97.55–98.72% of the volatiles of individual samples. The principal chemical components in flowers were bornyl acetate (15.40%), α-phellandrene (14.18%), p-cymene (9.64%), camphor (9.54%), β-linalool (8.61%), and α-thujone (7.06%). In leaves, the main components were p-cymene (20.42%), bornyl acetate (20.41%), α-phellandrene (13.67%), and β-linalool (5.46%). As for stems, trans-β-farnesene (17.95%), germacrene D (12.89%), β-phellandrene (12.70%), β-caryophyllene (10.18%), and bicyclogermacrene (8.01%) were the dominant volatile compounds. Comparative studies on the volatiles from various species of genus Dendranthema indicated that Dendranthema indicum var. aromaticum contains significantly more aroma compounds than its morphologically similar species.     

Volatile compounds in perianth and corona of Narcissus Pseudonarcissus cultivars

Narcissus pseudonarcissus (daffodil) is a valuable plant for the cosmetic, pharmaceutical and therapeutical traits. The flower volatile compounds (FVCs) of ten Narcissus pseudonarcissus cultivars were analyzed by Headspace/Solid Phase Micro Extraction-Gas Chromatography Mass Spectrometry (HS/SPME- GC/MS). 69 and 73 FVCs were detected in perianth and corona of the ten cultivars. The compounds are largely comprised of monoterpenes, sesquiterpene, benzenoid compounds and other minor compounds classes. Monoterpenes were major component among the FVCs, with beta-ocimene and beta-myrcene as the two major compounds in most perianths and coronas. The composition and content of the FVCs of different cultivars are quite different from each other.     

Analysis of volatile organic compounds in pleural effusions by headspace solid‐phase microextraction coupled with cryotrap gas chromatography and mass spectrometry

Headspace solid‐phase microextraction coupled with cryotrap gas chromatography and mass spectrometry was applied to the analysis of volatile organic compounds in pleural effusions. The highly volatile organic compounds were separated successfully with high sensitivity by the employment of a cryotrap device, with the construction of a cold column head by freezing a segment of metal capillary with liquid nitrogen. A total of 76 volatile organic compounds were identified in 50 pleural effusion samples (20 malignant effusions and 30 benign effusions). Among them, 34 more volatile organic compounds were detected with the retention time less than 8 min, by comparing with the normal headspace solid‐phase microextraction coupled with gas chromatography and mass spectrometry method. Furthermore, 24 volatile organic compounds with high occurrence frequency in pleural effusion samples, 18 of which with the retention time less than 8 min, were selected for the comparative analysis. The results of average peak area comparison and box‐plot analysis showed that except for cyclohexanone, 2‐ethyl‐1‐hexanol, and tetramethylbenzene, which have been reported as potential cancer biomarkers, cyclohexanol, dichloromethane, ethyl acetate, n‐heptane, ethylbenzene, and xylene also had differential expression between malignant and benign effusions. Therefore, the proposed approach was valuable for the comprehensive characterization of volatile organic compounds in pleural effusions.     

Detection and identification of volatile organic compounds in blood by headspace gas chromatography as an aid to the diagnosis of solvent abuse

A gas chromatographic method has been developed for the detection and identification of some volatile organic compounds in whole blood, plasma or serum. After incubation of the sample (200 μl) together with the internal standard solution in a sealed vial, a portion of the headspace in analysed using a 2-m glass column packed with 0.3% (w/w) Carbowax 20M on Carbopack C, 80–100 mesh. The column oven, after a 2-min isothermal period, is programmed from 35 to 175°C at 5°/min and held for 8 min. the effluent is monitored by both flame-ionisation and electron-capture detection, and peak assignment is by means of retention time and relative detector response.The method has proved applicable to the detection of bromchlorodifluoromethane, n-butane, carbon tetrachloride, chlorobutanol, cryofluorane (Halon 114), dichlorodifluoromethane (Halon 12), ethyl acetate, halothane, isobutane, isopropanol, isopropyl nitrate, methyl ethyl ketone, propane, tetrachloroethylene, toluene, 1,1,1-trichlorothane, 2,2,2-trichlorethanol, trichloroethylene and trichlorofluoromethane (Halon 11) in blood specimens obtained from patients suspected of abusing these agents.     

Characterization of volatile compounds of <Emphasis Type="Italic">Daucus crinitus</Emphasis>Desf. Headspace Solid Phase Microextraction as alternative technique to Hydrodistillation

Background  

Traditionally, the essential oil of aromatic herbs is obtained using hydrodistillation (HD). Because the emitted volatile fraction plays a fundamental role in a plant's life, various novel techniques have been developed for its extraction from plants. Among these, headspace solid phase microextraction (HS-SPME) can be used to obtain a rapid fingerprint of a plant's headspace. Daucus crinitus Desf. is a wild plant that grows along the west coast of Algeria. Only a single study has dealt with the chemical composition of the aerial part oils of Algerian D. crinitus, in which isochavicol isobutyrate (39.0%), octyl acetate (12.3%), and β-caryophyllene (5.4%) were identified. Using GC-RI and GC-MS analysis, the essential oils and the volatiles extracted from separated organs of D. crinitus Desf. were studied using HS-SPME.     

The valence bond calculations for conjugated hydrocarbons having 24–28 π‐electrons

A novel algorithm is introduced for coding all Slater determinants in the covalent space with conserved S_Z, the z component of total spin S for a classical valence bond (VB) model. It effectively minimizes the search time and the storing space in the central memory of the computer. In cooperation with symmetry reductions based on molecular point group and spin inversion, the VB calculations have been extended to benzenoid hydrocarbons of up to 28 π‐electrons that have 4×10⁷ configurations. The low‐lying states of benzenoids with 24, 26, and 28 π‐electrons have been obtained for 62 species. To rationalize the aromaticity of benzenoids in a VB scheme, the resonance energy per hexagon (REPH) is defined. A linear correlation between the REPH and the energy gap of the ground (singlet) state and the first excited (triplet) state for 89 benzenoids is established. © 2000 John Wiley & Sons, Inc. J Comput Chem 21: 856–869, 2000     

HS–SPME–GC–MS and Electronic Nose Reveal Differences in the Volatile Profiles of Hedychium Flowers

Floral fragrance is one of the most important characteristics of ornamental plants and plays a pivotal role in plant lifespan such as pollinator attraction, pest repelling, and protection against abiotic and biotic stresses. However, the precise determination of floral fragrance is limited. In the present study, the floral volatile compounds of six Hedychium accessions exhibiting from faint to highly fragrant were comparatively analyzed via gas chromatography–mass spectrometry (GC–MS) and Electronic nose (E-nose). A total of 42 volatile compounds were identified through GC–MS analysis, including monoterpenoids (18 compounds), sesquiterpenoids (12), benzenoids/phenylpropanoids (8), fatty acid derivatives (2), and others (2). In Hedychium coronarium ‘ZS’, H. forrestii ‘Gaoling’, H. ‘Jin’, H. ‘Caixia’, and H. ‘Zhaoxia’, monoterpenoids were abundant, while sesquiterpenoids were found in large quantities in H. coccineum ‘KMH’. Hierarchical clustering analysis (HCA) divided the 42 volatile compounds into four different groups (I, II, III, IV), and Spearman correlation analysis showed these compounds to have different degrees of correlation. The E-nose was able to group the different accessions in the principal component analysis (PCA) corresponding to scent intensity. Furthermore, the pattern-recognition findings confirmed that the E-nose data validated the GC–MS results. The partial least squares (PLS) analysis between floral volatile compounds and sensors suggested that specific sensors were highly sensitive to terpenoids. In short, the E-nose is proficient in discriminating Hedychium accessions of different volatile profiles in both quantitative and qualitative aspects, offering an accurate and rapid reference technique for future applications.     

Global Forcing Number of Benzenoid Graphs

A global forcing set in a simple connected graph G with a perfect matching is any subset S of E(G) such that the restriction of the characteristic function of perfect matchings of G on S is an injection. The number of edges in a global forcing set of the smallest cardinality is called the global forcing number of G. In this paper we prove several results concerning global forcing sets and numbers of benzenoid graphs. In particular, we prove that all catacondensed benzenoids and catafused coronoids with n hexagons have the global forcing number equal to n, and that for pericondensed benzenoids the global forcing number is always strictly smaller than the number of hexagons.     

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.     

Determination of the volatile constituents of ChineseCoriandrum sativum L. by gas chromatography—Mass spectrometry with solid-phase microextraction

Summary Fifteen main volatile compounds in ChineseCoriandrum sativum L. were separated and identified by gas chromatography—mass spectrometry (GC-MS) combined with solid-phase microextraction (SPME). Fresh ChineseCoriandrum sativum L. was ground and its volatile compounds were extracted by SPME with a 100 μm polydimethylsiloxane fiber. The fibers were desorbed in a GC injection liner at 250°C for 3 min. More than 15 peaks were separated by headspace SPME-GC-MS analysis. The main compounds in headspace ofCoriandrum sativum L. identified by mass spectrometry included decanal, 2-decenal, 1-decanol,trans-2-decen-1-ol,trans-2-decen-1-al,trans-2-tridecenal etc, which were verified by reference compounds. Their relative contents were calculated on basis of peak areas. SPME extraction conditions and capillary chromatography column used to separate the volatile compounds were investigated.     

Identification and Evaluation of Aromatic Volatile Compounds in 26 Cultivars and 8 Hybrids of Freesia hybrida

Freesia hybrida is a group of cultivars in the genus Freesia with a strong floral scent composed of diverse volatile organic compounds (VOCs). In this study, the VOCs of 34 F. hybrida were extracted and analyzed by headspace solid phase microextraction and gas chromatography mass spectrometry (HS-SPME-GC-MS). A total of 164 VOCs whose relative contents were higher than 0.05% were detected. The numbers of VOCs in all germplasms differed between 11 to 38, and the relative contents ranged from 32.39% to 94.28%, in which most germplasms were higher than 80%. Terpenoids, especially monoterpenes, were the crucial type of VOCs in most germplasms, of which linalool and D-limonene were the most frequently occurring. Principal component analysis (PCA) clearly separated samples based on whether linalool was the main component, and hierarchical clustering analysis (HCA) clustered samples into 4 groups according to the preponderant compounds linalool and (E)-β-ocimene. Comparison of parental species and hybrids showed heterosis in three hybrids, and the inherited and novel substances suggested that monoterpene played an important role in F. hybrida floral scent. This study established a foundation for the evaluation of Freesia genetic resources, breeding for the floral aroma and promoting commercial application.