三种固相微萃取头对厚皮甜瓜果汁香气成分萃取效果分析

采用美国Supelco公司生产的Carboxen^TM/PDMS、DVB/CAR/PDMS和PDMS/DVB 3种固相微萃取头萃取厚皮甜瓜(Cucumis melo L.)果汁中的香气成分,并用气质联用仪对香气成分进行检测。结果表明, 3种萃取头检测到的香气成分均以酯类为主,醇类和醛类较少。Carboxen^TM/PDMS萃取的香气成分相对含量达91.55%,特征香气成分相对含量达到63.01%;DVB/CAR/PDMS也可以全面萃取甜瓜香气,但香气成分与特征香气的相对含量及总峰面积比Carboxen^TM/PDMS的低;PDMS/DVB萃取头吸附的香气成分种类最少,相对含量最低。可见,对厚皮甜瓜果汁香气成分的萃取以Carboxen^TM/PDMS萃取头较好。     

Headspace analysis identifies indole and 1-octen-3-ol as the “coal tar” odor of <Emphasis Type="Italic">Tricholoma inamoenum</Emphasis>

The odor emanating from sporocarps of Tricholoma inamoenum has been described as resembling “coal tar”. To characterize the compounds responsible for this odor, volatile chemicals released from T. inamoenum sporocarps were collected using solid phase microextraction (SPME). Subsequent analysis by gas chromatography-mass spectrometry (GC-MS) showed only indole and 1-octen-3-ol, so these compounds must be responsible for the “coal tar” odor of T. inamoenum. Mushroom pileus size was a factor in the amount of indole produced; larger mushrooms released 25-times more indole than smaller ones. A comparison of SPME and CH₂Cl₂ solvent extraction of sporocarps showed major differences in the volatile organic compounds. Benzaldehyde and phenyl acetaldehyde were the major compounds in the solvent extracts, but were not detected in the SPME experiments. Tissue disruption of the mushroom before solvent extraction showed up to a 40-fold increase in the amount of 1-octen-3-ol present.     

糖蜜草挥发性成分HS-SPME-GC-MS分析

本文首次采用顶空固相微萃取技术(HS-SPME)提取该植物挥发性成分,然后通过气质联用技术(GC-MS)结合保留指数以及标样对照对化学成分进行了定性,并通过峰面积归一化法计算出各组分的相对百分含量。试验确定了PDMS/DVB固相微萃取对糖蜜草挥发物的萃取效果最好,并从中鉴定出33种化合物占总挥发性成分的90.94%,主要为烷烃和萜烯类化合物。该研究为开发糖蜜草作为水稻螟虫的驱避植物进行害虫安全有效防治提供理论依据,并为驱避性挥发物的田间应用奠定基础。     

Effect of CO₂ and 1-octen-3-ol attractants for estimating species richness and the abundance of diurnal mosquitoes in the southeastern Atlantic forest, Brazil

Studies have shown that both carbon dioxide (CO?) and octenol (1-octen-3-ol) are effective attractants for mosquitoes. The objective of the present study was to evaluate the attractiveness of 1-octen-3-ol and CO? for diurnal mosquitoes in the southeastern Atlantic forest. A Latin square experimental design was employed with four treatments: CDC-light trap (CDC-LT), CDC-LT and 1-octen-3-ol, CDC-LT and CO? and CDC-LT with 1-octen-3-ol and CO?. Results demonstrated that both CDC-CO? and CDC-CO?-1-octen-3-ol captured a greater number of mosquito species and specimens compared to CDC-1-octen-3-ol; CDC-LT was used as the control. Interestingly, Anopheles (Kerteszia) sp. was generally attracted to 1-octen-3-ol, whereas Aedes serratus was the most abundant species in all Latin square collections. This species was recently shown to be competent to transmit the yellow fever virus and may therefore play a role as a disease vector in rural areas of Brazil.     

Identification of the Predominant Volatile Compounds Produced by Aspergillus flavus

A culture of Aspergillus flavus grown on moistened wheat meal was homogenized with a blendor, and the resulting slurry was vacuum-distilled at 5 mm of Hg and 35 C. The aqueous distillate was collected in traps cooled to -10 to -80 C. The culture volatiles were extracted from the distillate with CH(2)Cl(2), and, after removal of the bulk of the solvent, the concentrated volatiles were examined by packed-column gas chromatography. Nineteen peaks were observed, and coupled gas chromatography-mass spectrometry was employed to identify the larger components. The compounds identified were: 3-methyl-butanol, 3-octanone, 3-octanol, 1-octen-3-ol, 1-octanol, and cis-2-octen-1-ol. The two octenols were the predominant compounds, and sufficient sample was trapped from the gas chromatograph for infrared analyses; this confirmed the mass spectral identifications and permitted the assignment of the cis designation to 2-octen-1-ol. Both oct-1-en-3-ol and cis-2-octen-1-ol are thought to be responsible for the characteristic musty-fungal odor of certain fungi; the latter compound may be a useful chemical index of fungal growth.     

Field studies on efficacy of host odour baits for the biting midge Culicoides impunctatus in Scotland

The efficacy of some putative attractants for the biting midge Culicoides impunctatus (Goetghebuer) (Diptera: Ceratopogonidae) was assessed using odour-baited 'delta traps' and suction traps. 1-octen-3-ol was confirmed as a potent olfactory attractant for C. impunctatus when released at 0.06mg/h. Acetone (23mg/h) and a mix of six phenolic compounds (phenol, 3-ethylphenol, 4-ethylphenol, 3-methylphenol, 4-methylphenol and 4-propylphenol), at undetermined release rate, also significantly increased delta trap catches compared to unbaited controls. When tested in combination, there was evidence of synergism between CO2 (0.2L/min) and acetone, 1-octen-3-ol or cow urine, trap catches being, respectively, 4.7, 6.2 and 9.3-fold greater than for CO2 alone. Highest catches were obtained with triple bait combinations comprising cow urine + acetone + CO2 or cow urine + 1-octen-3-ol+CO2, which increased trap catches by X 22 and X 24, respectively, compared to CO2 alone. Culicoides impunctatus was found to be extremely sensitive to CO2 and responses, gauged over two field seasons, showed a significant dose-dependent increase in catch across the entire range of release rates (0.2-2.5 L/min). Responses to these release rates, ranging from small to large mammal equivalents, emphasized the important role of CO2 in host location by C. impunctatus. Uses of olfactory attractants for monitoring and control of Culicoides are reviewed on the basis of these results.     

The response of Culex quinquefasciatus (Diptera: culicidae) to traps baited with carbon dioxide, 1-octen-3-ol, acetone, butyric acid and human foot odour in Tanzania

The responses of Culex quinquefasciatus Say to traps baited with carbon dioxide, 1-octen-3-ol, acetone, butyric acid and human foot odour were studied in the field in Muheza, north-east Tanzania using Counterflow Geometry (CFG) and Centers for Disease Control (CDC) traps. It was found that significantly more C. quinquefasciatus responded to foot odour collected on nylon stockings than to clean nylon stockings (P < 0.05). Significantly more mosquitoes were caught in a CFG trap baited with carbon dioxide than in traps with either human foot odour, acetone or butyric acid. It was also found that in an outdoor situation a carbon dioxide baited CDC unlit trap collected over 12 times more C. quinquefasciatus than an unbaited CDC unlit trap and nine times more mosquitoes than CDC traps baited with 1-octen-3-ol alone (P < 0.05). The number of mosquitoes caught in a CDC trap baited with 1-octen-3-ol did not differ significantly from that of the unbaited CDC trap (P > 0.05). These results indicate that the Afrotropical C. quinquefasciatus respond significantly better to traps baited with carbon dioxide than to either octenol, acetone or butyric acid, and that human foot odour contains stimuli to which C. quinquefasciatus is attracted under field conditions.     

Performance evaluation of a wood-chip based biofilter using solid-phase microextraction and gas chromatography-mass spectroscopy-olfactometry

A pilot-scale mobile biofilter was developed where two types of wood chips (western cedar and 2 in. hardwood) were examined to treat odor emissions from a deep-pit swine finishing facility in central Iowa. The biofilters were operated continuously for 13 weeks at different air flow rates resulting in a variable empty bed residence time (EBRT) from 1.6 to 7.3 s. During this test period, solid-phase microextraction (SPME) PDMS/DVB 65 microm fibers were used to extract volatile organic compounds (VOCs) from both the control plenum and biofilter treatments. Analyses of VOCs were carried out using a multidimentional gas chromatography-mass spectrometry-olfactometry (MDGC-MS-O) system. Results indicated that both types of chips achieved significant reductions in p-cresol, phenol, indole and skatole which represent some of the most odorous and odor-defining compounds known for swine facilities. The results also showed that maintaining proper moisture content is critical to the success of wood-chip based biofilters and that this factor is more important than media depth and residence time.     

Antennal responses of tsetse to analogues of the attractant 1-octen-3-ol

Abstract. Antennal movement responses of male Glossina morsitans morsitans Westwood to twelve analogues of the tsetse olfactory attractant 1-octen-3-ol were investigated to determine their structure-activity relationships. The results indicate that the chemoreceptors which perceive this set of kairomones may not be highly specific. Activity is dependent on the length of the alkyl chain; also homologues with odd alkyl chains such as 3-buten-2-ol, 1-hexen-3-ol and 1-octen-3-ol evoked higher antennal responses than homologues with even alkyl chains such as l-nonen-3-ol, 1-hepten-3-ol and 1-penten-3-ol. Comparison of the activities of eight carbon structural variants of 1-octen-3-ol showed that the structural requirements for activity of the functional end of the molecule may not be rigid; thus, 1-octyn-3-ol elicited relatively high responses. However, low responses to 1-octene and 3-octanol showed that both the π electron system as well as the oxygen function are important for activity. Laboratory bioassay findings indicate that compounds such as 1-octyn-3-ol, 3-buten-2-ol, allyl alcohol and 1-octen-3-one which evoke antennal responses 2–3 times greater than the control have attractive properties and preliminary field investigations show that 3-buten-2-ol and allyl alcohol significantly increase trap catches.     

Studies on the aroma of maté (Ilex paraguariensis St. Hil.) using headspace solid-phase microextraction

Volatile and semi-volatile components of maté (Ilex paraguariensis St. Hil.) were analysed by headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography and mass spectrometry. Five SPME fibres coated separately with 100 microm poly(dimethylsiloxane) (PDMS), 65 microm PDMS-divinylbenzene (DVB), 70 microm carbowax (CW)-DVB, 85 microm carboxen (CAR)-PMDS or 50/30 microm DVB-CAR, were tested. Seventy compounds were identified in the sample headspace, including propanal, (E)-2-pentenal, hexanal, (E)-2-hexenal, 6-methyl-5-hepten-2-one, (E,Z)-2,4-heptadienal, (E,E)-2,4-heptadienal, (E,Z)-3,5-octadien-2-one, beta-cyclocitral, 3-ethyl 4-methyl-(1H)-pyrrole-2,5-dione, alpha-ionone, geranylacetone, beta-ionone, dihydroactinidiolide and caffeine. Extraction parameters such as temperature, time and sample mass were studied and optimized. The best conditions for trapping volatile and semi-volatile compounds were obtained using a DVB-CAR fibre at 80 degrees C for 60 min with a sample mass starting from 100 mg in a vial of 4 mL.     

Rapid identification of microbial VOCs from tobacco molds using closed-loop stripping and gas chromatography/time-of-flight mass spectrometry

Several microbial volatile organic compounds (MVOCs) that can serve as potential chemical markers for microbial contamination in tobacco have been identified. Four different fungal species, Aspergillus niger (AN), A. ornatus (AO), Pencillium chrysogenum (PC) and Rhizopus stolonifer (RS), commonly reported in moldy tobacco were cultured and screened for MVOCs. Because the MVOCs emitted by a microbial species are substrate specific, the fungal strains were separately grown on potato dextrose agar (PDA) and tobacco products. MVOCs from the mold cultures grown on PDA and tobacco products were extracted using closed-loop stripping analysis (CLSA) and identified by gas chromatography/time-of-flight mass spectrometry (GC/TOF-MS). Some of the prominent tobacco mold markers identified by this method include: 1-octen-3-ol; 2-octen-1-ol; 2-methyl-1-butanol; 3-methyl-1-butanol; 1-octene and 2-pentanone. In particular, 1-octen-3-ol was detected in all the mold cultures and moldy tobacco samples analyzed. Olfactory evaluation of 1-octen-3-ol indicated a characteristic musty odor and the odor threshold was determined to be approximately 200 ng/ml. The limits of detection for 1-octen-3-ol using GC/TOF-MS and GC/mass selective detector (MSD) in the full-scan mode and selected ion monitoring (SIM) mode were investigated. The CLSA-GC/TOF-MS demonstrates a fast, sensitive and semi-quantitative analytical technique for screening tobacco materials for the presence of mold via chemical markers of microbial contamination.     

Electroantennogram responses of the stable fly, Stomoxys calcitrans, to components of host odour

Abstract. Electroantennograms (EAGs) were recorded from laboratory-reared male and female Stomoxys calcitrans (L.) in response to a range of synthetic chemicals known to be electrophysiologically-active for other biting flies. Of the eight compounds initially tested, only two - 1-octen-3-ol and 3-methylphenol - consistently elicited larger electroantennograms (EAGs) than did control treatments; 1-octen-3-ol was the most potent. EAG recovery time was inversely correlated with EAG amplitude. EAGs recorded with primary C₂-C₁₂ carbon chain-length primary aliphatic alcohols peaked at octan-1–ol with pentan-1-ol, hexan-1-ol and heptan-1-ol also eliciting EAG responses significantly larger than the controls. When different C₈ carbon chain compounds and nonane were tested: 1-octen-3-ol elicited the largest EAGs followed by, in decreasing activity, octan-1-ol, 1-bromooctane, octan-3-ol, octanal, 2-octanone, octanoic acid and nonane. The EAG response of 1-octen-3-ol increased sigmoidally with dose, with the threshold at between 2 and 20 ng, and the peak response at 200 μg on filter paper. EAGs larger than control were also elicited by entrained ox odour and ox breath. The behavioural implications are discussed.     

Indole and 3-chloroindole: The source of the disagreeable odor of Hygrophorus paupertinus

The odor emanating from sporocarps of Hygrophorus paupertinus is disagreeable and fecal-like. Solid phase microextraction (SPME) and analysis by gas chromatography-mass spectrometry (GC-MS) showed 1-octen-3-ol, indole and 3-chloroindole were responsible for the odor. This is the first case in which 3-chloroindole has been identified from a terrestrial organism.     

Development of a solid phase microextraction-gas chromatography method to determine N-hydroxymethyl-N-methylformamide and N-methylformamide in urine

A headspace solid phase microextraction (SPME) method has been developed to determine metabolites of dimethylformamide, N-hydroxymethyl-N-methylformamide, and N-methylformamide (NMF) as NMF in urine by gas chromatography with nitrogen-phosphorus detector (GC-NPD). An SPME holder with a 65-microm PDMS/DVB fiber coating was used. Optimal desorption conditions were 250 degrees C for 1 min, adsorption at 80 degrees C for 15 min, and 3.00 mL of sample in the headspace vial. The method presented good resolution, repeatability, recovery, detection limit, ruggedness and response linearity.     

成熟度对印度块菌香气成分的影响

研究成熟度对印度块菌Tuber indicum香气成分的影响,并测定成熟印度块菌的关键香气成分。将3种不同成熟度的印度块菌,以固相微萃取(SPME)技术为香气富集方法,利用气相色谱-质谱联用(GC-MS)分析其香气成分。结果表明未成熟印度块菌中仅检测出4种香气成分,中度成熟阶段检测出8种,成熟阶段检测出13种,而且成熟阶段检测出的香气成分大多都是前人报道过对块菌香气有贡献的成分;通过计算成熟块菌各香气组分的香气活度值(OAV),可知二甲基硫醚、2,3-丁二酮、3-甲基正丁醛、2-甲基正丁醛、己醛、1-辛烯-3-醇这6种物质是印度块菌的关键香气成分(OAV>1)。     

贮藏保鲜中SO2伤害对红提葡萄香气组分的影响

采用固相微萃取技术及气相-质谱联用技术对不同SO2漂白伤害程度的红提果实进行香气成分的提取与鉴定,以探讨SO2漂白伤害对贮藏葡萄果实中香气组分的影响.结果表明,果实经漂白伤害后其具有芳香气味的气体所占比重明显下降,主要成分醇类化合物下降最多,而具有刺激难闻气味的酸类化合物所占比重明显上升;此外,4-萜烯醇、正己醇、月桂醇、松油醇、芳樟醇、橙花醇、乙酸萜烯酯及青叶醛等具有葡萄特征性香味的化合物在香气中所占比例明显下降或消失,而异辛醇、1-辛烯-3-醇、壬酸、辛酸、正癸酸、乙酸、己酸、2,6-二叔丁基对甲酚及2-丁基-5-(2-甲基丙基)-噻吩等具有臭味或刺激性气味的化合物出现或所占比重上升.说明,SO2伤害对红提果实香气的影响主要表现为香味化合物所占比重的减少或消失及异味化合物的产生.     

Development of a Headspace Solid‐Phase Microextraction Gas Chromatography‐Mass Spectrometry Method to Study Volatile Organic Compounds (VOCs) Emitted by Lavender Roots

A headspace solid‐phase microextraction (HS‐SPME) method combined with gas chromatography‐mass spectrometry (GC/MS) was developed and optimized for the extraction and the analysis of volatile organic compounds (VOCs) from lavandin and fine lavender roots. Optimal parameters to extract volatile molecules from ground and intact roots were determined using a divinylbenzene‐carboxen‐polydimethylsiloxane (DVB/CAR/PDMS) coating fiber at 70 °C for 60 min. A total of 99 VOCs, including 40 monoterpenoids, 15 sesquiterpenoids, 1 diterpenoid and 2 coumarins were detected. The main compounds detected in lavandin roots were fenchol, borneol, and coumarin. Performances of the optimized SPME GC/MS method were evaluated via the comparison of VOC emissions between roots from different cultivars of fine lavender (7713 and maillette) and lavandin (abrial and grosso). Chemometric analysis, using partial least squares‐discriminant analysis (PLS‐DA), suggests fifteen significant features as potential discriminatory compounds. Among them, β‐phellandrene allows discrimination between lavender and lavandin varieties.     

Solid-phase microextraction and the human fecal VOC metabolome

The diagnostic potential and health implications of volatile organic compounds (VOCs) present in human feces has begun to receive considerable attention. Headspace solid-phase microextraction (SPME) has greatly facilitated the isolation and analysis of VOCs from human feces. Pioneering human fecal VOC metabolomic investigations have utilized a single SPME fiber type for analyte extraction and analysis. However, we hypothesized that the multifarious nature of metabolites present in human feces dictates the use of several diverse SPME fiber coatings for more comprehensive metabolomic coverage. We report here an evaluation of eight different commercially available SPME fibers, in combination with both GC-MS and GC-FID, and identify the 50/30 μm CAR-DVB-PDMS, 85 μm CAR-PDMS, 65 μm DVB-PDMS, 7 μm PDMS, and 60 μm PEG SPME fibers as a minimal set of fibers appropriate for human fecal VOC metabolomics, collectively isolating approximately 90% of the total metabolites obtained when using all eight fibers. We also evaluate the effect of extraction duration on metabolite isolation and illustrate that ex vivo enteric microbial fermentation has no effect on metabolite composition during prolonged extractions if the SPME is performed as described herein.     

HS-SPME-GC/MS analysis of the volatile compounds of <Emphasis Type="Italic">Achillea collina</Emphasis>: Evaluation of the emissions fingerprint induced by <Emphasis Type="Italic">Myzus persicae</Emphasis> infestation

A Headspace Solid-phase Microextraction (HS-SPME) method combined with Gas Chromatography-Mass Spectrometry (GC/MS) was developed and optimized to extrat and analyze the volatile compounds of aerial parts of Achillea collina Becker ex Rchb. and to investigate the effect of the phlem feeding aphid Myzus persicae Sulzer on the Volatile Organic Compounds (VOCs) emitted by the infested plants. The extraction of 1 g of powdered freeze dried plant samples for 120 min at 30°C using divinylbenzene-carbowax-polydimethylsiloxane (DVB/CAR/PDMS) fiber showed the highest area counts for the majority of the volatile compounds. Overall, 62 and 80 volatile compounds were detected in control and infested plant samples respectively. In A. collina infested plants, we observed a great increase in both monoterpenes and sesquiterpenes fractions. Several changes among alcohols also occurred, particularly regarding Z-3-hexen-1-ol, E-3-hexen-1-ol and E-2-hexen-1-ol proposing these compounds as herbivore-induces plant volatiles (HIPVs). New perspective for agricultural practice may derive from the opportunity to identify novel herbivores-induced plant VOCs active as plant protection agents.     

Exploiting volatile organic compounds in crop protection: A systematic review of 1-octen-3-ol and 3-octanone

The 21st century has brought new challenges to the agri-food industry due to population growth, global warming, and greater public awareness of environmental issues. Ensuring global food security for future generations is crucial. However, pests, weeds, and diseases still significantly contribute to crop losses, and the availability of effective conventional synthetic pesticides is decreasing. To address this, new and diverse pest management tools are needed. One pest management tool showing potential for invertebrate pest management is the exploitation of volatile organic compounds (VOCs)—in particular, the compounds 1-octen-3-ol and 3-octanone. This review aims to explore the extent to which 1-octen-3-ol and 3-octanone show potential in the future management of invertebrate crop and animal pests. A significant increase in the rate of publication of literature on the use of 1-octen-3-ol and 3-octanone in crop protection since 2018 is identified by this review, therefore, showing the potential importance of these compounds for use in future pest management. This review also identifies key interactions between naturally occurring biosynthesised 1-octen-3-ol and 3-octanone, and a range of invertebrate targets. Many of these interactions with key crop pests are sourced from the taxonomic families Lamiaceae, Fabaceae, and Trichomaceae. However, analysis of the practical application of these sources in an integrated pest management programme identifies clear limitations with the use of naturally occurring biosynthesised 1-octen-3-ol and 3-octanone. Rather, future focus should be placed on the development and exploitation of synthesised nature identical 1-octen-3-ol and 3-octanone for use as a biopesticide product. Overall, 1-octen-3-ol and 3-octanone show potential for exploitation in future crop protection, being abundant in source and diversity of invertebrate interactions. However, their use as a naturally occurring biosynthesised chemical is likely not practical for direct implementation in crop protection. Rather, focus should be placed on the development and exploitation of synthesised nature identical variants of these compounds for use as a biopesticide.