树苔浸膏中关键气味活性化合物

香气是评价浸膏品质的重要指标,通过研究浸膏中的香气成分可以为浸膏的应用和质量控制提供参考依据。利用固相微萃取(SPME)和溶剂辅助风味蒸发(SAFE)两种方法结合GC-MS对树苔浸膏中的挥发性香气成分进行分析。通过香气提取物稀释分析(AEDA)对树苔浸膏中的香气活性物质进行了鉴定,结果表明:利用SPME和SAFE两种前处理方法共鉴定出102种挥发性成分,香气活性成分为27种,其中香气稀释因子(flavordilutionfactor,FD因子)较高(FD≥9)的为β-苔黑酚羧酸甲酯、戊酮酸乙酯、苔黑酚羧酸乙酯、赤星衣酸乙酯、壬酸乙酯、庚酸乙酯、苯乙酸乙酯。进一步的定量及气味活度值(OAV)计算确认关键气味活性化合物为β-苔黑酚羧酸甲酯、苔黑酚羧酸乙酯、庚酸乙酯。     

苦荞提取物的关键香气成分分析

采用固相微萃取(SPME)结合气相色谱-质谱联用技术(GC-MS)分析苦荞提取物中的挥发性成分;同时采用气相色谱-嗅闻仪(GC-O)结合香气提取稀释分析(AEDA)确定其香气活性成分,通过对香气活性成分定量并计算其香气活性值(OAV)最终确定苦荞提取物的关键性香气成分。结果显示,SPME-GC-MS在苦荞提取物中共鉴定出92种挥发性成分,包括酯类28种、醛类7种、醇类9种、酮类7种、酸类6种、烯烃8种、烷烃20种、其他类7种;经GC-O嗅闻仪共鉴定出17种香气活性化合物,定量结果显示,苯甲醇(8637.40μg/kg),苯乙醛(3150.47μg/kg)、D-柠檬烯(3080.00μg/kg)含量较高;结合稀释因子(FD)和香气活性值(OAV)推测,苯甲醛(FD=81,OAV=5)、二甲基三硫(FD=243,OAV=48)、苯甲醇(FD=81,OAV=9)、苯乙醛(FD=729,OAV=787)、丙二酸二乙酯(FD=81,OAV=1.2)5种物质对苦荞提取物的风味贡献最大,是苦荞提取物的关键香气成分。     

陈皮的挥发性香气分析

采用溶剂萃取法(SE)结合溶剂辅助风味蒸发法(SAFE)提取陈皮中的挥发性成分,利用GC-MS和气相色谱-嗅闻联用技术(GC-O)对陈皮和九制陈皮中的挥发性风味物质进行鉴定.共鉴定出95种挥发性成分,46种香气活性物质.为了确定关键香气物质,采用香气提取物稀释分析法(AEDA)对两种陈皮的香气活性成分作进一步分析,结果...     

陈皮的挥发性香气分析

为了深入探究陈皮的挥发性香气成分,采用溶剂辅助风味蒸发法（SAFE）提取陈皮中的挥发性成分,利用气相色谱-质谱联用仪（GC-MS）和气相色谱-嗅闻联用技术（GC-O）对陈皮和九制陈皮中的挥发性风味物质进行鉴定,结果共鉴定出93挥发性成分,46种香气活性物质。为了确定关键香气物质,采用香气提取物稀释分析法（AEDA）对两种陈皮的香气活性成分作进一步分析,结果显示：萜烯类、醇类和醛类化合物是主要的香气活性物质,其中柠檬烯、月桂烯是两者共有的关键香气成分。此外,1,4-二甲基-4-乙酰基-1-环己烯、橙花醇、香茅醛、肉豆蔻醛和α-甜橙醛是陈皮中的关键香气成分;香兰素、香芹酚、紫苏醇、芳樟醇、香芹酮和β-紫罗酮是九制陈皮中关键香气成分。通过对两种陈皮的关键性风味物质进行对比分析,确定出两种陈皮中对风味贡献较大的香气化合物及其差异组分,从而为陈皮类产品的开发提供理论支撑。     

AEDA/GC-MS分析新鲜芫荽香气成分

采用溶剂辅助风味蒸发法（SAFE）结合气相色谱-质谱联机（GC-MS）,通过双柱对新鲜芫荽中的挥发性成分进行鉴定,并通过谱库检索和保留指数比对,共计从新鲜芫荽中鉴定出化合物87种,其中烃类28种,醛类20种,醇类22种,酸类4种,酯类7种,酮类3种,杂环及其他类3种。通过香气提取物稀释分析法 (AEDA) 结合气相色谱-嗅闻技术（GC-O）对新鲜芫荽进行分析,共鉴定出21种活性香气成分,其中关键香气的物质有5种 (FD≥81),分别是反-2-十二烯醛、反-2-十三烯醛、反-2-十四烯醛、3-甲硫基丙醛、反-2-癸烯醛。     

新鲜芫荽关键性香气成分的鉴定与分析

采用溶剂辅助风味蒸发法(SAFE),结合气相色谱-质谱联机(GC-MS),通过双柱对新鲜芫荽中的挥发性成分进行了鉴定,并通过谱库检索和保留指数比对,共计从新鲜芫荽中鉴定出化合物87种,其中烃类28种,醛类20种,醇类22种,酸类4种,酯类7种,酮类3种,杂环及其他类3种。通过芳香萃取物稀释分析法(AEDA),结合气相色谱-嗅闻技术(GC-O)对新鲜芫荽进行了分析,共鉴定出21种活性香气成分,其中关键性香气成分有5种[香气稀释因子(FD)≥81],分别是反-2-十二烯醛、反-2-十三烯醛、反-2-十四烯醛、3-甲硫基丙醛、反-2-癸烯醛。     

豆豉鲮鱼挥发性风味成分分析

为确定豆豉鲮鱼的关键性风味成分,稳定产品品质,采用固相微萃取(SPME)法和同时蒸馏萃取(SDE)法提取豆豉鲮鱼中的挥发性风味成分,结合气相色谱-质谱联用技术(GC-MS)进行分析。共鉴定出113种挥发性化合物,两种提取方法共同检测出来的成分有26种。对同时蒸馏萃取结果进行气相色谱-嗅闻(GC-O)检测,共确定了豆豉鲮鱼9种关键性风味成分,分别为2-正戊基呋喃、2,5-二甲基吡嗪、2-乙基吡嗪、2,3,5-三甲基吡嗪、2-十一烯醛、茴香脑、2-乙酰基吡咯、可卡醛、肉桂酸乙酯。     

生韭菜与炒韭菜挥发性风味物质的对比分析

采用溶剂辅助风味蒸发法(SAFE)结合气相色谱-质谱联用仪(GC-MS),通过双柱(DB-WAX和DB-5毛细管柱)定性对生韭菜和炒韭菜的挥发性成分进行鉴定,分别检测出83和127种挥发性成分,生韭菜和炒韭菜中物质含量的差异主要体现在酯类和醛类化合物。采用芳香萃取物稀释分析法(AEDA)结合气相色谱-嗅闻-质谱联用仪(GC-O-MS)分析样品,鉴定出生韭菜的关键性香气成分17种〔香气稀释因子(FD)≥27〕,炒韭菜的关键性香气成分10种(FD≥27),其中共有的关键性香气成分为甲基烯丙基二硫醚,具有辛辣、蒜香气味。生韭菜的关键性香气成分主要为硫醚类物质,为生韭菜提供辛辣、酸臭气味。炒韭菜的关键性香气成分主要为醛类和杂环类化合物,为炒韭菜提供烤香、焦香气味。     

HS-SPME-GC-MS／O分析品牌香皂的特征呈香成分

应用固相微萃取法（SPME）富集结合GC-MS分离检测技术,研究了品牌香皂中的挥发性成分,并采用气相色谱一嗅觉检测（GC一（））技术对品牌香皂中的呈香化合物进行了筛选和鉴定。分析结果表明,HS-SPME-GC-MS与GC-O芳香萃取物稀释分析（AEDA）方法相结合不仅能分析被试样品的组成,还可用来鉴别香皂中呈香化合物的类别、香气强度及各自对总体香气的贡献。     

SPME和SAFE对比分析炸花椒油挥发性风味成分

采用固相微萃取(SPME)和溶剂辅助风味蒸发(SAFE)两种萃取方法结合气相色谱-质谱联用(GC-MS)对炸花椒油的挥发性风味成分进行分析。结果表明,共鉴定出103种挥发性化合物,包括烃类36种、醛类12种、酮类8种、醇类28种、酯类12种、醚类2种、杂环及其他类5种。SPME法和SAFE法萃取出的挥发性风味成分的差异主要体现在烃类、酯类和醚类化合物,SPME法中相对含量较高的酯类化合物和独有的醚类化合物使得其测定结果更接近炸花椒油的风味。     

调整联合装置操作,努力提高装置效益

本文着重分析了丙烯生产过程中液化气损失的原因,通过调整催化稳定操作和改造液化气汽化器及不凝气系统,丙烯收率增加0.73%。气分操作波动减小,同时装置能耗较以前降低2.97千克标油/吨原料。     

Novel poly(diphenylacetylene)s with both alkyl and silyl groups as gas permeable membranes: Synthesis, desilylation, and gas permeability

Diphenylacetylenes having a dimethyloctylsilyl group and an alkyl group at para positions [Me₂n-C₈H₁₇SiC₆H₄CCC₆H₄R; R = H (1a), i-Pr (1b), t-Bu (1c), n-Bu (1d)] and having only an alkyl group [PhCCC₆H₄R; R = i-Pr (1B), t-Bu (1C)] were synthesized and then polymerized with TaCl₅/n-Bu₄Sn catalyst to provide the corresponding poly(diphenylacetylene)s (2a, 2b, 2c, 2d, 2B, and 2C). The formed polymers afforded tough free-standing membranes by casting from toluene solutions. Desilylation reaction of Si-containing membranes (2a-d) was carried out with trifluoroacetic acid to give the desilylated membranes (3a-d). The permeability of these membranes to O₂, N₂, and CO₂ were determined. All the Si-containing membranes exhibited almost the same gas permeability. The desilylation of Si-containing membranes of 2a-c resulted in large increase of gas permeability. No apparent increasing of gas permeability was observed in the desilylation of 2d. To clarify the effects of desilylation, CO₂ diffusivity (D(CO₂)), CO₂ solubility (S(CO₂)), and fractional free volume (FFV) of the polymer membranes were investigated. The S(CO₂) values of desilylated membranes were much larger than that of Si-containing counterparts. The D(CO₂) and FFV of membranes of 2a-c increased through desilylation. The desilylated membrane of 3d had small D(CO₂) value and almost the same FFV compared with 2d. Further, the comparison of the permeability between three types of membranes with the same chemical structure revealed that the microvoids were not generated by the desilylation of membranes of poly(diphenylacetylene)s containing alkyl groups.     

Synthesis of novel poly(diphenylacetylene)s with both trimethylsilyl and alkyl groups: The effect of desilylation on gas permeability

Diphenylacetylenes having both a trimethylsilyl group and an alkyl group at para positions [Me₃SiC₆H₄CCC₆H₄R; R = Et (1a), n-Bu (1b), t-Bu (1c), n-C₈H₁₇ (1d)] and having only an alkyl group [PhCCC₆H₄R; R = n-Bu (1B), n-C₈H₁₇ (1D)] were synthesized and then polymerized with TaCl₅/n-Bu₄Sn catalyst to provide the corresponding poly(diphenylacetylene)s (2a, 2b, 2c, 2d, 2B, and 2D). The formed polymers except 2c afforded tough free-standing membranes by casting from toluene solutions. Desilylation reaction of the Si-containing polymer membranes (2a, 2b, 2d) was carried out with trifluoroacetic acid, and the desilylated polymer membranes (3a, 3b, 3d) were obtained. The permeability to O₂, N₂, and CO₂ were determined for the obtained polymer membranes. All the desilylated membranes showed lower gas permeability than the Si-containing counterparts. To clarify the effects of the desilylation further, CO₂ diffusivity, CO₂ solubility, and fractional free volume (FFV) of the polymer membranes were investigated. The FFV and CO₂ diffusivity decreased upon desilylation, while CO₂ solubility hardly varied.     

生物制品中残留甲醛含量衍生-气相色谱检测方法的建立及初步应用

目的建立生物制品中残留甲醛含量衍生-气相色谱检测方法,并进行验证及初步应用。方法采用液体进样方式,毛细管色谱柱(SH-Rxi-5MS,30 m×0. 25 mm×0. 25μm)分离,FID检测器检测,外标法定量,测定样品中残留甲醛含量。进样前,对照品及样品使用2,4-二硝基苯肼(2,4-dinitrophenyl-hydrazine,2,4-DNPH)衍生处理,考察不同衍生条件(包括衍生时间、衍生温度和提取溶剂等)对甲醛衍生及提取效率的影响。色谱条件:初始温度为150℃,保持1 min;以20℃/min的速率升温至250℃,保持10 min;检测器温度为250℃,进样口温度为250℃,分流比为10∶1;载气为N2;进样量为1μL。对建立的方法进行重复性、准确性验证及初步应用。结果游离甲醛质量浓度在1~100μg/mL范围内时,浓度与峰面积呈良好的线性关系,回归方程为A=3 789. 7 C-1 030. 2,相关系数为0. 999 8。用建立的方法重复检测甲醛标准液6次,相对标准偏差(relative standard deviation,RSD)为1. 73%;在百白破疫苗样品中加入质量浓度分别为2、10和50μg/mL的甲醛标准溶液,测定的回收率分别为90. 15%、83. 16%和90. 35%;检测9种不同类型疫苗中残留甲醛,其中百白破、乙肝疫苗(酿酒酵母)、乙肝疫苗(CHO)和流感病毒裂解疫苗中可检出残留甲醛;检测6个厂家生产的百白破疫苗中残留甲醛含量,均低于《中国药典》三部(2015版)规定的限值,除C厂家某批次产品检出的残留甲醛低于方法的定量限以外,其余厂家残留甲醛含量在6. 81~43. 89μg/mL之间。结论建立了一种标准化检测生物制品中游离甲醛含量的气相色谱法,该方法线性、重复性、准确性良好,适用于疫苗中残留甲醛含量的检测。     

Synthesis and gas permeability of nitrated and aminated Poly(diphenylacetylene)s

Poly(diphenylacetylene) [PDPA] derivatives were nitrated using a mixture of nitric acid and sulfuric acid. Nitration of poly[1-(p-trimethylsilyl)phenyl-2-phenylacetylene] (1a) proceeded, and the nitro groups were substituted to trimethylsilyl groups on benzene rings. The degree of nitration (DN) increased with reaction time, and it reached 0.41 for 3.0 h. Fluorine-containing PDPA (1b and 1c) showed less reactivity for nitration, and the DNs were only 0.18 and 0.06, respectively, under the same conditions. Nitration of PDPAs having n-butyl and t-butyl groups (1d and 1e) afforded the nitrated PDPAs, whose DN were 0.20 and 0.14, respectively. Reduction of nitro groups on PDPAs proceeded quantitatively to produce the corresponding PDPAs possessing amino groups (3a-e). Aminated PDPAs exhibited high CO₂ permselectivity compared to the corresponding non-aminated PDPAs. The CO₂ permeability coefficients of aminated PDPAs (3a-d) were lower than those of the corresponding polymers (1a-d) because the polymer chain packing was strengthened by the intermolecular interaction between polar amino groups, but t-butyl group-containing aminated PDPA (3e) showed high CO₂ permeability than 1e because the chain packing was weakened by the steric repulsion of bulky t-butyl groups.     

Synthesis of Palm Oil-Based Diethanolamides

In this work, Epoxidized Palm Olein (EPO_o) was blended with Refined Bleached Deodorized Palm Kernel Olein (RBDPKO_o) in a range of 10–100% (w/w) to react with diethanolamine (DEA) with a 1:3 molar ratio to produce diethanolamides that retained some epoxides. The epoxidized diethanolamides are proposed as a new type of vegetable oil derived polyols for rigid polyurethane. The optimal reaction temperature is 110 °C for 5 h. In addition, the optimal amount of starting materials were determined to be 40% (w/w) of EPO_o blended with 60% (w/w) of RBDPKO_o. The diethanolamides appeared as non-viscous liquid at room temperature with a viscosity of 990.08 cP at 25 °C and 427.09 cP at 40 °C, a cloud point of 21 °C, a pour point of 12 °C and 0.78% of retained oxirane oxygen contents (OOC). The hydroxyl and the amine values of the diethanolamides were determined as 351.85 mg KOH/g sample and 4.5 mg KOH/g sample, respectively. In addition, chemical elucidation of the diethanolamides with functional epoxides was carried out using Gas Chromatography (GC) and Gas Chromatography Mass Spectrometry (GCMS) for the purpose of process development and quality control.     

Diffusion of gases and vapors through methacrylates with oxyethylene units in the pendent chain

The diffusion of He, Ar, O₂, N₂, CO₂, CH₄, CH₃CH₃ and CH₂CH₂ has been determined in three polymethacrylates with one, two and three oxyethylene units as side chains. For these three rubbery polymers we have used the acronyms PEEMA, PDEMA and PTEMA, respectively. The results have been compared to those of poly(ethyl methacrylate) on one hand, and on the other with previous results on methacrylates of varying length alkyl side chains. It has been found that the oxyethylene units side chains methacrylates show diffusion coefficients which are slightly lower than those methacrylates bearing alkyl side chain, when comparing polymers with the same number of atoms in the side chain. These diffusion data are put in relation to relevant structural features such as the glass transition temperature and the fractional free volume of both families of rubbery methacrylates.     

Enhanced NO2 gas sensor device based on supramolecularly assembled polyaniline/silver oxide/graphene oxide composites

Herein, we report a successful synthesis of supramolecularly assembled polyaniline/silver oxide/graphene oxide composite (PANI/Ag₂O/GO) for enhanced NO₂ gas sensing application. The PANI/Ag₂O/GO composite was synthesized by facile stirring followed by an ultrasonication process. The prepared material was characterized by different techniques such as x-ray diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and Raman-scattering spectroscopy. The detailed analysis revealed that the average crystallite sizes of PANI/Ag₂O and PANI/Ag₂O/GO composites were found to be 37.37 nm and 41.55 nm, respectively. FESEM and TEM analysis showed coral-like rough-surfaced and extensively agglomerated morphology for PANI and ultrathin flexible sheet-like morphology for GO. Ag₂O nanoparticles with diameters 20–30 nm were well incorporated in the GO sheets and PANI matrix in the case of PANI/Ag₂O/GO composites. The synthesized materials were used to make resistive sensor devices that had a high response to NO₂ gas. The fabricated sensors were examined at various temperatures to obtain the optimal sensing temperature. The fabricated NO₂ gas sensor device based on PANI/Ag₂O/GO composite exhibited a highest sensitivity of 5.85 for 25 ppm at an optimized temperature (100 °C) as compared to the pure PANI (2.5) and PANI/Ag₂O composite (3.25). Further, the fabricated sensor device based on PANI/Ag₂O/GO composite was also examined at different NO₂ gas concentrations.     

Gas foaming of segmented poly(ester amide) films

Biodegradable segmented poly(ester amide)s, based on dimethyl adipate, 1,4-butanediol and N,N′-1,2-ethanediyl-bis[6-hydroxy-hexanamide], with two distinct melting transitions were gas foamed using carbon dioxide (CO₂). Polymer films were saturated with CO₂ at 50 bar for 6 h after which the pressure was released. The samples were immersed in octane at the desired temperature after which foaming started immediately. Just above the lower melt transition the polymers retain adequate mechanical properties and dimensional stability, while the chain mobility increased sufficiently to nucleate and expand gas cells during the foaming process. In this way semi-crystalline poly(ester amide)s can be gas foamed below the flow temperature.Two poly(ester amide)s with 25 mol% (PEA2,5-25) and 50 mol% (PEA2,5-50) of bisamide segment content were foamed at 70 and 105 °C, respectively. The storage modulus (G′) of both pure polymers at the onset foaming temperature is 50-60 MPa. Closed-cell foams were obtained with a maximum porosity of ∼90%. The average pore size of PEA2,5-25 ranges from 77 to 99 μm. In contrast, the average pore size of PEA2,5-50 is in between 2 and 4 μm and can be increased to 100 μm by lowering the CO₂ saturation pressure to 20 bar. The porosity of PEA2,5-50 foams using this saturation pressure decreased to 70%.     

CO2-permselective membranes of crosslinked poly(vinyl ether)s bearing oxyethylene chains

Cationic copolymerizations of vinyl ether monomers having a triethylene glycol segment [2-(2-(2-methoxyethoxy)ethoxy)ethyl vinyl ether (TEGMVE)] with vinyl ether monomer having a methacrylate unit [2-(2-vinyloxyethoxy)ethyl methacrylate: VEEM] were performed to obtain crosslinkable copolymers [poly(TEGMVE-VEEM)] with different composition rates. Methacrylate groups in poly(TEGMVE-VEEM)s partially reacted to give crosslinked polymer membranes. The free-standing membranes of poly(TEGMVE-VEEM)s obtained at monomer feed ratios of 6:1, 10:1, and 14:1 were too brittle, while their composite membranes with PTFE sheet were tough enough to measure gas permeability. All the membranes of poly(TEGMVE-VEEM) showed high CO₂/N₂ selectivity (PCO₂/PN₂$P_{{\text{CO}}_2}/P_{{\text{N}}_2}$ = 35–54) because of their high CO₂ solubility selectivity (SCO₂$S_{{\text{CO}}_2}$/SN₂$S_{{\text{N}}_2}$ = 38–61). The gas permeability increased as the composition ratio of VEEM decreased, and the composite membrane of poly(TEGMVE-VEEM)(14:1) showed the highest CO₂ permeability (PCO₂$P_{{\text{CO}}_2}$ = 410 barrers) among the present polymer membranes.