不同产地香叶油中挥发性成分的GC-TOF/MS分析

为探讨不同产地香叶油中挥发性成分的差异,采用气相色谱-飞行时间质谱法进行挥发性成分定性,并通过质谱库检索,结合保留指数比对,从法国、广西和云南3个产地的香叶油中分别鉴定出91、71和63种挥发性成分,分别占总峰面积的97.24%、99.35%和98.15%。不同产地香叶油挥发性成分在组成和含量上存在一定的差异,3者共有成分46个,且主要的共有成分为香茅醇、甲酸香茅酯、香叶醇、甲酸香叶酯、芳樟醇、玫瑰醚等化合物。通过保留指数来鉴定香叶油中挥发性成分,提高化合物定性的准确性。该方法稳定可靠,适用于香叶油挥发性成分的分析。     

GC/MS法结合保留指数分析留兰香油成分

利用GC/MS结合保留指数分析留兰香油成分,并用峰面积归一化法计算各组分相对含量。分析并确定33个化合物,占留兰香油成分97.53%,其主要成分为香芹酮(56.19%),柠檬烯(21.26%),α-松油醇(4.81%),薄荷酮(2.12%),(Z)-二氢香芹酮(2.01%),芳樟醇(1.42%),β-蒎烯(1.46%),α-蒎烯(1.16%),3-辛醇(0.84%),莰烯(0.83%),月桂烯(0.69%)等。采用保留指数来鉴别同系物及同分异构体,提高对留兰香油成分定性准确性,研究结果可为留兰香油产品开发和应用提供理论依据。     

色谱指纹图谱分析在香精香料质量控制中的应用

针对复杂的烟草香精香料化学成分,首先采用了3种不同的提取技术:同时蒸馏萃取(SDE),液液萃取(LLE)和固相微萃取(SPME)进行提取,在比较了它们的效果之后,采用了SDE和GC-MS相结合的方法建立了一种新的色谱指纹图谱方法。通过12个来自不同批次的烟草香精样品建立的指纹图谱分析,结果显示有39种挥发性成分(占总量的86.54%)能够被识别,其中有28个共有峰,基于共有峰的相对保留时间和相对峰面积进行的相似性分析表明:12个烟草香精样品的相似度均大于0.8,这说明不同批次的样品品质在一定程度上是稳定的。通过相似度比较和主成分分析,这种色谱指纹图谱能够轻松区别烟草香精和烟叶提取物,完全能够用于烟草香精的质量控制。     

雅安藏茶贮藏过程中滋味和风味成分的变化

对贮藏0.5,6,11年的雅安藏茶的康砖品种茶叶的水浸出物、茶红素、茶黄素、茶褐素、氨基酸、儿茶素、茶多酚7种滋味物质含量进行检测,采用顶空固相微萃取(HS-SPME)和GC/MS对香气成分进行提取、鉴定,旨在探明贮藏时间对雅安藏茶滋味和风味成分的影响。结果表明,随着贮藏时间延长,水浸出物和茶褐素含量分别从28.442%和3.201%增加至48.116%和3.996%,茶红素、游离氨基酸、儿茶素含量从2.671%、0.859%、61.64%降低至2.182%、0.382%、41.59%(P0.05),导致陈年雅安藏茶具有汤色红褐、滋味醇厚而不苦涩,但缺少新茶特有回甘的特点。3个年份的康砖茶叶共检测出75种主要香气成分,包括己醛、a-蒎烯、甲基庚烯酮、2-正戊基呋喃等,贮藏11年藏茶中酯类、烯烃类及芳香类物质的含量最高,这可能是雅安藏茶陈香的主要贡献者。     

基于体外抑菌作用的金莲花系列制剂谱-效关系研究

通过体外抑菌活性检测结合化学指纹图谱分析,对金莲花系列制剂4种剂型进行再评价。以药用生药量为指标,采用试管二倍稀释法测定金莲花系列制剂的最小抑菌生药量;采用高效液相色谱法建立金莲花系列制剂的指纹图谱;通过"中药色谱指纹图谱相似度评价系统(药典委员会2004A版)"对金莲花4种指纹图谱进行相似度分析;基于"Statistical Product and Service Solutions"软件,对抑菌活性值和色谱指纹图谱数据进行相关性分析,简述指纹图谱特征峰与抑菌作用的相关性。金莲花4种制剂指纹图谱相似度良好。金莲花口服液抑菌生药量最小,各成分相对峰面积与抑菌生药量相关性良好,峰1、3、4、5、6、7、8、9、11、12与生药量负相关,峰2、13与生药量正相关。其中峰1、7、8、9、11对金黄色葡萄球菌抑菌生药量相关性与其他峰相比有显著性差异(P0.05),峰3(P0.05)、12(P0.01)对大肠杆菌的抑菌生药量相关性有显著差异。结果表明金莲花口服液剂型质量较优,运用谱-效相关性分析能较好地对剂型进行再评价。     

联苯菊酯纯度标准物质的研制

研制了联苯菊酯纯度标准物质.采用红外光谱、质谱和熔点法对联苯菊酯纯品进行定性鉴定,并利用Dean-Switch切换、气相色谱-质谱联用方法对杂质进行定性分析,确认了8种杂质的结构.优化并建立了高效液相色谱-二极管阵列检测器(HPLC-DAD)、气相色谱-氢火焰离子化检测器(GC-FID)进行主成分定值.利用卡尔费休法、电感耦合等离子体质谱法、灼烧法等方法进行无机杂质的分析.均匀性和稳定性检验结果表明,研制的联苯菊酯纯度标准物质均匀性良好,稳定时间3年,纯度值为99.6%,扩展不确定度为0.2%(k=2).     

三种竹叶中挥发性成分分析及对比研究

目的 研究对比苦竹、麻竹、紫竹竹叶中的挥发性成分,旨在开发新型抗菌抗氧化成分资源,为天然安全的抗菌抗氧化包装及保鲜技术开发提供基础。方法 采用水蒸气蒸馏法提取3种竹叶挥发油成分,并用气相色谱-质谱联用（GC-MS）技术结合保留指数（RI）对挥发油成分进行鉴定分析。结果 从3种竹叶挥发油中分别鉴定出61,49,68种挥发性成分,以酯类（16.358%～31.930%）、酮类（18.206%～24.033%）、烃类（3.873%～19.632%）、醛类（8.436%～15.414%）和醇类（8.448%～11.182%）化合物为主。3种竹叶挥发油含24种相同成分,以棕榈酸异丙酯（9.826%～22.408%）、4-羟基-3-甲基苯乙酮（5.870%～7.078%）、苯乙醛（3.746%～4.486%）等为主。结论 3种竹叶挥发油相同成分均相对含量较高,这些含量较高的物质均有良好的抗菌抗氧化特性。     

百里香-丁香罗勒精油抗菌纸对草莓的防腐保鲜效果

目的研究一种精油抗菌纸及其对草莓的防腐保鲜效果。方法从百里香等5种植物精油中筛选出对灰霉等4种微生物具有强抑制作用的精油,并对其成分进行气相色谱-质谱(GC-MS)分析。将筛选出的精油结合聚乙烯醇涂布于纸张表面制得抗菌纸,采用熏蒸法测试其对供试微生物的抑制作用,并研究其对草莓的保鲜效果。结果百里香精油和丁香罗勒精油对4种供试微生物的抑菌效果较强。百里香精油的主要成分为百里香酚和香芹酚,其峰面积百分比分别为77.04%和16.46%;丁香罗勒精油的主要成分为丁香酚和β-石竹烯,其峰面积百分比分别为77.95%和18.80%。涂布液中精油体积分数为4%的抗菌纸(双层涂布,下同)抑菌效果最强。精油体积分数为3%的抗菌纸抑菌效果次之,但其对维持草莓感官品质、抑制草莓的腐烂、延缓其菌落总数上升具有最佳的效果,显著优于精油体积分数为4%,2%和1%的抗菌纸及原纸(P0.05)。抗菌纸对草莓可溶性固形物含量无明显影响。结论体积分数为3%的百里香-丁香罗勒精油抗菌纸对草莓具有较好的保鲜效果。     

不同产地黑老虎挥发油成分的GC-MS分析研究

采用水蒸气蒸馏法,GC-MS分离检测技术,分析研究了福建、广西、广东三个不同产地黑老虎挥发油的成分。共鉴定出51种化合物,挥发油总量福建占77.82%,广西占78.62%,广东占78.83%。其中有20种为共有成分,主要包括δ-荜澄茄烯、β-石竹烯、α-可巴烯、葎草烯、别香橙烯、γ-衣兰油烯等,分别占各自挥发油总量的51.45%(福建),38.08%(广西),62.95%(广东)。结果表明,不同产地黑老虎挥发油含量及化学成分组成差异较大。     

静态顶空–气相色谱质谱联用结合感官评价分析3种胶黏剂中的气味物质

目的 探究纸包装材料用胶黏剂中挥发性气味物质及其影响。方法 选择10名感官评价员对3种胶黏剂样品的气味强度进行嗅辨分析,使用顶空–气相色谱质谱法(Headspace-Gas Chromatography-Mass Spectrometry, HS-GC-MS)采集挥发性化合物数据,利用MS–DIAL软件解卷积、NIST质谱库和保留指数实现对物质的定性分析,计算各化合物的相对峰面积含量和相对气味活性值(Relative Odour Activity Value, ROAV),用于确定样品气味特征的关键贡献物质及其影响。结果 3种胶黏剂样品的感官影响差异明显,样品中共检测出45种挥发性物质,以酯类、醇类、酮类和芳香烃等化合物为主,其中可筛选出8种对胶黏剂的气味特征贡献最大的关键气味物质,包括丙酸丁酯、乙酸丁酯、3–甲基–4–庚酮、乙苯等。结论 胶黏剂的气味主要与使用的复杂化学成分有关,其生产加工过程应当引起高度关注。     

"翔安邨"清香型高梁酒主要香气成分的GC/MS分析

采用气相色谱／质谱法对以乙醚提取的“翔安郦”白酒中香气成分进行了分析鉴定,共分离和初步鉴定22个芳香性成分。其中主要芳香性成分是乙酸乙酯、乳酸乙酯、辛酸乙酯、棕榈酸乙酯、异戊醇、异丁醇等。     

琯溪蜜柚鲜花香气成分的气相色谱/质谱分析

采用乙醚浸提、水蒸气蒸馏和溶剂萃取溪蜜柚鲜花的香气成分,用气相色谱-质谱(GC/MS)进行分析鉴定,首次鉴定出19种香气成分,并对其各种香气成分的相对含量进行了统计分析。本文为利用溪蜜柚鲜花开发高附加值天然鲜花香精提供了科学依据。     

Modified cemented stem fixation in hip arthroplasty with computer based analysis – Experimental results

27 cemented stems were implanted in fresh‐frozen human cadaver femora with third generation antegrade cementing technique and with prechilled vacuum‐mixed and pre‐pressurized Palacos R bone cement. 3 groups with different implantation techniques were compared according to the achieved cement mantle thickness distribution. Group 1 (modified stem fixation): 7 canulated stems inserted over guidetubes that were fixed in distal synthetic plugs (3 Willert CF‐30 and 4 flanged Charnley stems). The guidetubes served simultaneously for stem centralization and evacuation of the intramedullary cavity. Group 2: 12 stems with distal centralizers with fins (4 flanged Charnley, 8 anatomic cemented AC), and Group 3: 8 stems without centralizer (4 Willert CF‐30 and 4 flanged Charnley). For analysis, each femur was cut into mean 25 cross‐sections (range, 22 ‐ 31). Contact radiographs were taken and digitized with a sampling distance of 0.12mm (204.8 dpi). Using a custom‐made computer program (FemStat 1.001), the cement mantle thickness was determined at mean 650 implant surface points per cross section. Results: The percentage of critical cement mantle thickness was lower for the canulated stems with guidetube. Here 14.1 % of the measurements were smaller than 2mm. For the stems with distal centralizer and without centralizer this was 28.3 % and 28.2 % (p = 0.003 and p = 0.002, U‐test). Cement mantles smaller than 1mm were also reduced for group 1 (2.8 % compared with 4.7 % and 7.5 %) but this was not significant (p = 0.384 and p = 0.094). The stems without centralizers had only slightly inferior cement mantles if compared to stems with distal centralizers with fins (for < 2mm p = 0.571, for < 1mm p = 0.305). Comparing different cementing techniques for one constant type of prosthesis (Charnley) the canulated stems with guide tubes provided a significantly better cement mantle thickness than the stems with distal centralizers (for < 2mm 10.3 % compared with 26.6 %, p = 0.029; for < 1mm 1.5 % compared with 3.4 %, p = 0.343). Distal centralizers failed, as the intramedullary cavity is elliptic in cross section and the gaps between the wings caused malposition. For all stems in group 3 improvement of the cement mantle thickness was predominantly achieved in the distal and middle third of the femur. Conclusion: The implantation technique with canulated stems inserted over a guidetube allows superior stem positioning leading to a more favourable cement mantle.     

Assessment of carcinogenic risk due to inhalation of polycyclic aromatic hydrocarbons in PM10 from an industrial city: a Korean case-study

This study investigated the effects of meteorological conditions and spatial variations on the toxicity of polycyclic aromatic hydrocarbons (PAHs) in airborne PM(10) in Ulsan, the largest industrial city in Korea. Daily PM(10) samples were collected on quartz microfiber filters using high volume samplers located in a downtown area, a residential area and an industrial area of Ulsan during spring and summer sampling periods. Sixteen individual PAHs were extracted into a mixture solution of dichloromethane and n-hexane (1:1, v/v) in an ultrasonic bath and were analyzed using a high performance liquid chromatography system with an ultra-violet detector (HPLC-UVD). The average total PAH concentrations from the three representative sampling sites of Ulsan ranged from 16.15 to 57.12 ng/m(3) in spring and from 11.11 to 34.56 ng/m(3) in summer. The toxicity equivalent concentrations (TEQs) of the PAHs in PM(10) of Ulsan ranged from 1.82 to 13.1 ng/m(3), with an average level of 4.17 ng/m(3). The highest TEQs were found in the downtown area, which had an average value of 6.30 ng/m(3) in spring and 5.52 ng/m(3) in summer. BaP and DahA were identified as the major carcinogenic PAHs that contributed to 34.8 and 59.4% of the total carcinogenic potency of PAHs in PM(10) in Ulsan. The identified TEQs were highly correlated (r(2) = 0.73-0.90, p<0.01) with the total PAH concentrations for each area. The TEQs showed a significant correlation (p < 0.01) with the concentration of air pollutants, including PM(10), PM(2.5) and NO(2).     

氮气吸附静态容量法测定固体材料比表面积不确定度评定

氮气吸附静态容量法是测定固态材料比表面积最常用的方法,以吸附质和吸附剂发生多层物理吸附为基础,使用商用比表面积分析仪,依据标准GB/T 19587-2004《气体吸附BET法测定固态物质比表面积》测量了α-氧化铝的比表面积;详细分析了仪器测试过程中各个环节带来的不确定度分量,得出:不确定度主要来源于仪器校准、质量称量的重复性以及线性最小二乘法拟合数据,最后计算得到测量结果为(79.3±3.4)m2/g(k=2)。     

Liquid-liquid-liquid microextraction for sample preparation of biological fluids prior to capillary electrophoresis.

Methamphetamine as a model compound was extracted from 2.5-mL aqueous samples adjusted to pH 13 (donor solution) through a thin phase of 1-octanol inside the pores of a polypropylene hollow fiber and finally into a 25-microL acidic acceptor solution inside the hollow fiber. Following this liquid-liquid-liquid microextraction (LLLME), the acceptor solutions were analyzed by capillary zone electrophoresis (CE). Extractions were performed in simple disposable devices each consisting of a conventional 4-mL sample vial, two needles for introduction and collection of the acceptor solution, and a 8-cm piece of a porous polypropylene hollow fiber. From 5 to 20 different samples were extracted in parallel for 45 min, providing a high sample capacity. Methamphetamine was preconcentrated by a factor of 75 from aqueous standard solutions, human urine, and human plasma utilizing 10(-1) M HCl as the acceptor phase and 10(-1) M NaOH in the donor solution. In addition to preconcentration, LLLME also served as a technique for sample cleanup since large molecules, acidic compounds, and neutral components were not extracted into the acceptor phase. Utilizing diphenhydramine hydrochloride as internal standard, repetitive extractions varied less than 5.2% RSD (n = 6), while the calibration curve for methamphetamine was linear within the range 20 ng/microL to 10 micrograms/mL (r = 0.9983). The detection limit of methamphetamine utilizing LLLME/CE was 5 ng/mL (S/N = 3) in both human urine and plasma.     

High-performance nitrate-selective electrodes containing immobilized amino acid betaines as sensors

Ten nitrate-selective electrodes based upon rubbery membranes containing various betaine salts as sensors covalently bound to a cross-linked polystyrene-block-polybutadiene-block-polystyrene (SBS) polymer have been produced. The membranes were robust, highly selective, and effective over a pH range of 2-8. The best nitrate-selective electrode fabricated contained 10% m/m dicumyl peroxide, 40% 2-nitrophenyloctyl ether, 6.5% triallyl leucine betaine chloride and 43.5% SBS. The characteristics of this electrode were a linear Nernstian range of 1 x 10(-1) to 5 x 10(-6) mol dm(-3) NO3-, a limit of detection of 3.4 x 10(-7) mol dm(-3) NO3-, and a selectivity coefficient for nitrate against chloride, K(NO3-,Cl-)pot, of 3.4 x 10(-3). These figures represent a significant improvement on current commercial nitrate sensors. Response times were 1 min or less; stability of response and electrode lifetime in continuous use was also very satisfactory.     

Selective trace enrichment of chlorotriazine pesticides from natural waters and sediment samples using terbuthylazine molecularly imprinted polymers

Two molecularly imprinted polymers were synthesized using either dichloromethane or toluene as the porogen and terbuthylazine as the template and were used as solid-phase extraction cartridges for the enrichment of six chlorotriazines (deisopropylatrazine, deethylatrazine, simazine, atrazine, propazine, and terbuthylazine) in natural water and sediment samples. The extracted samples were analyzed by liquid chromatography/diode array detection (LC/DAD). Several washing solvents, as well as different volumes, were tested for their ability to remove the matrix components nonspecifically adsorbed on the sorbents. This cleanup step was shown to be of prime importance to the successful extraction of the pesticides from the aqueous samples. The optimal analytical conditions were obtained when the MIP imprinted using dichloromethane was the sorbent, 2 mL of dichloromethane was used in the washing step, and the preconcentrated analytes were eluted with 8 mL of methanol. The recoveries were higher than 80% for all the chlorotriazines except for propazine (53%) when 50- or 100-mL groundwater samples, spiked at 1 microg/L level, were analyzed. The limits of detection varied from 0.05 to 0.2 microg/L when preconcentrating a 100-mL groundwater sample. Natural sediment samples from the Ebre Delta area (Tarragona, Spain) containing atrazine and deethylatrazine were Soxhlet extracted and analyzed by the methodology developed in this work. No significant interferences from the sample matrix were noticed, thus indicating good selectivity of the MIP sorbents used.     

食品包装粘合剂中挥发性化合物的HS-SPME/GC-O-MS分析

目的研究食品包装材料常用的5种粘合剂样品中的挥发性成分。方法采用顶空固相微萃取法(HS-SPME)提取粘合剂中的挥发性化合物,再利用气相色谱质谱联用技术(GC-MS)结合气相色谱嗅觉测量法(GC-O),分析计算挥发性化合物的保留指数、量化强度值、气味和浓度,鉴定粘合剂中的主要挥发性化合物,并对挥发性组分及浓度进行定性、定量和对比分析。结果采用HS-SPME/GC-O-MS法能有效地鉴别和确认粘合剂中挥发性化合物的类别及浓度;各粘合剂的挥发性气味成分在组成和含量上存在差异,粘合剂中有33种嗅感物质,其中乙酸、丁酸、丁酸甲酯、1-丁醇和壬醛存在于大部分的粘合剂。结论粘合剂中含量最丰富的挥发性化合物是乙酸,其含量范围为22 900~8 930 000 ng/g,最佳的萃取纤维时间为15 min,最优萃取纤维是DVB/CAR/PDMS。     

Use of booster seats by Michigan children 4-8 years of age

This study reports the results of a statewide survey of restraint use by 4–8-year-old children in Michigan conducted between July 13 and 29, 2004. In this study, 3420 4–8-year-old children were observed traveling in passenger cars, vans/minivans, sport-utility vehicles, and pickup trucks. Restraint use was estimated for children traveling in all vehicles combined, as well as for each vehicle type separately. Children's restraint use was also calculated by the sex, age, and belt use of the driver. Separate estimates were also made of the restraint use of 4–8-year-old children by the combination of sex and belt use of the driver. Overall, 8.6 ± 5.9% of 4–8-year-old children were seated in a booster seat, 48.8 ± 10.3% were wearing a safety belt, 5.1 ± 3.4% were seated in a child safety seat, and the remaining 37.5 ± 11.5% were traveling completely unrestrained. When examining the rates by vehicle type, booster seat use was highest among children riding in sport-utility vehicles and lowest for those in pickup trucks. Surprisingly, children riding in passenger cars were more likely to be completely unrestrained than those in any other type of vehicle. While the sex of the driver did not seem to influence the restraint use of target-aged children, the driver's age did seem to have an effect. Booster seat use was quite low (0.6%) for children traveling with a driver over the age of 60, compared to 7.0 and 9.1% for those riding with drivers 16–29 and 30–59 years of age, respectively. The safety belt use of the driver also had a substantial influence on children's restraint use. Irrespective of driver sex, children riding with belted drivers were traveling in booster seats about 10% of the time, while those riding with unbelted drivers were only in booster seats 1–2% of the time.