气质联用仪法测定奶粉中多环芳烃

研究了奶粉中多环芳烃的气相色谱/质谱(GC/MS)测定方法. 样品经甲醇-KOH皂化后用甲苯提取, 提取液经微孔滤膜过滤后用气相色谱质谱仪测定其含量, 外标法定量. 结果16种PAHs的回收率范围为92.0%～106%;RSD为2.2%～4.7%. 方法能同时分离16种PAHs, 适合于奶粉中多环芳烃的分析测定.     

气相色谱/质谱法测定熏肉中的多环芳烃

建立了熏肉中多环芳烃的气相色谱/质谱(GC/MS)测定方法。样品经正己烷-丙酮(体积比为1∶1)超声波提取、氧化铝柱净化后,用GC/MS分离测定。优化了25种多环芳烃(PAHs)化合物的分离测定条件。结果 25种PAHs回收率范围为48.5%-106.5%;日内(n=7)相对标准偏差为3.75%-7.95%。方法具有灵敏度高、准确度好、能同时分离测定20余种多环芳烃化合物的优点,适合于熏肉中多环芳烃化合物的分析测定。     

利用GC/MS测定海洋中贻贝、牡蛎体内的多环芳烃

应用毛细管柱气相色谱／质谱（GC／MS）联用技术对贻贝,牡蛎体内的几种多环芳烃含量进行了分析研究,贻贝,牡蛎样品经超声提取,层析分离后,由GC／MS测定,采用选择性离子检测模式,定性,定量检出了几种多环芳烃。     

高效液相色谱-电喷雾银离子诱导电离飞行时间质谱定性分析高沸点多环芳烃

建立了高效液相色谱-电喷雾飞行时间质谱联用技术快速鉴别高沸点多环芳烃的方法。多环芳烃经色谱柱分离后,通过柱后添加AgNO3溶液诱导其在电喷雾离子源中电离,生成多环芳烃[M]+及其复合[M+Ag]+和[2M+Ag]+特征离子,根据所获得的各特征离子的精确分子量和分子式,可实现多环芳烃类化合物的快速鉴别。将本方法用于美国环保局(USEPA)规定的16种优先控制多环芳烃及原油中多环芳烃类化合物的分析鉴别,结果表明,四环以上的PAHs质谱信号良好,说明本方法适用于四环以上的高分子量、高沸点多环芳烃类化合物的分析鉴别。     

分散固相萃取-气相色谱-串联质谱法测定蔬菜中多环芳烃及卤代多环芳烃

建立了同时检测蔬菜中16种多环芳烃(PAHs)和11种卤代多环芳烃(X-PAHs)污染水平的分散固相萃取-气相色谱-串联质谱(GC-MS/MS)分析方法。样品中的多环芳烃和卤代多环芳烃经正己烷提取,N-丙基乙二胺吸附剂(PSA)和十八烷基键合硅胶吸附剂(C18)分散固相萃取净化剂净化,气相色谱-串联质谱方法测定,外标法定量。16种PAHs和11种X-PAHs在50,100和200μg/kg添加浓度下的回收率为74.7%～115.1%,相对标准偏差为1.6%～15.3%,方法检出限为0.03～7.4μg/kg。     

全二维气相色谱-氢火焰离子化检测器定性定量分析柴油中的多环芳烃

提出了全二维气相色谱-氢火焰离子化检测器(GC×GC-FID)定性定量分析柴油中多环芳烃的方法。利用全二维气相色谱-飞行时间质谱法(GC×GC-TOF MS)确定柴油芳烃的4个族组成,分别为非芳烃、一环芳烃、二环芳烃和三环⁺芳烃,获得37种定性化合物;采用峰面积归一化法对多环芳烃进行定量。结果表明：柴油质控样中多环芳烃测定值的相对误差绝对值不大于5.0%;对柴油样品进行回收试验,回收率为95.7%～104%,测定值的相对标准偏差(n=6)为1.7%～4.3%。方法用于7种实际柴油样品分析,并与NB/SH/T 0806-2022进行比对,结果显示两种方法测定值的相对误差绝对值均不大于5.0%。     

基于GC/Q-TOF MS技术鉴定S-zorb汽油中噻吩类化合物

结合气相色谱分离技术和MS/MS串联质谱筛查技术,通过选定目标母离子进行碰撞诱导解离,获取精确质量子离子信息,实现汽油馏分中噻吩类化合物的痕量筛查分析.选取5种不同碳数取代噻吩类化合物作为标准物绘制定量标准曲线,建立了基于气相色谱-四极杆串联飞行时间质谱(GC/Q-TOF MS)直接测定汽油中噻吩类化合物的方法.利用该...     

喷气燃料裂解产物中芳烃的全二维气相色谱-质谱分析

采用全二维气相色谱-质谱联用仪(GC×GC-MS),通过优化程序升温和调制周期,建立了喷气燃料裂解产物中芳烃的定性定量分析方法。该方法对多环芳烃(PAH)同分异构体具有良好的分离能力。利用MS检测器谱库检索结果、芳烃标准品及相关的文献报道,对喷气燃料裂解产物中常见的单环芳烃、二环芳烃、三环芳烃及四环芳烃等共27种芳烃进行了准确定性,并利用外标GC×GC-FID法对其进行定量。定量结果表明,芳烃含量均随着裂解产气率的增加而增大,当裂解产气率达到22%时,二环芳烃开始产生,且其含量随着裂解产气率的增加呈指数形式增加。该方法与传统的气相色谱-质谱相比,具有更好的分离及定性能力,可应用于复杂样品的分离及其定性定量分析。     

聚丙烯酸树脂涂层HS-SPME-GC-MS监测城市污水中的芳香烃化合物

采用聚丙烯酸树脂涂层-固相微萃取-气相色谱-质谱(PA—SPME—GC—MS)联用技术,在优化的萃取条件下检测了城市污水中的苯系物和多环芳烃等芳香烃化合物．该方法的最低检出限达12ng／L水平,相对标准偏差为1．7％～9．8％．     

气相色谱质谱法测定化妆品中9种多环芳烃

建立了气相色谱质谱法测定化妆品中9种多环芳烃的分析方法。化妆品中的萘、苯并[a]蒽、、苯并[b]荧蒽、苯并[j]荧蒽、苯并[k]荧蒽、苯并[e]芘、苯并[a]芘、二苯并[a,h]蒽等9种多环芳烃用甲醇超声提取后,用环己烷液-液萃取后浓缩,经硅胶-中性氧化铝柱净化后,采用气相色谱-质谱测定。多环芳烃浓度在0.05～2 mg/L范围内,质量浓度与其峰面积呈良好的线性关系。在低、中、高3个添加水平下,9种多环芳烃化合物的平均回收率为81.6%～100.2%,相对标准偏差为1.3%～5.8%。方法可用于化妆品中多环芳烃的检测。     

Facile synthesis methodology and characterization studies of silica-decorated hybridized anisotropic nanotubes and nanosheets

Carbonaceous nanomaterials and their derivatives have been inspired tremendous enthusiasm in the scientific community. They have been excogitated as the encouraging attributes and the qualified dispersed phase to develop multi-functional composites. Particularly, graphene and carbon nanotube (anisotropic fillers) have gained substantial research interest owing to their promising characteristics. This highlights an innovative technique to synthesize hybridized nanotube and nanosheet. Initially, parent materials have been synthesized: The pristine CNT has been modified by acid mixture solution, and reduced graphene oxide has been prepared by chemical reduction method. Henceforth, the self-assembly in situ sol–gel technique has been endorsed here. The synthesized nanohybrids have been characterized by different spectroscopic techniques: FTIR, Raman, UV, and XPS to confirm the attachment of multifunctionalities; meanwhile, the composition and stability have been investigated from XRD and TGA plots. The magnitude of surface charge and particle size distribution have been evaluated for the parent and hybridized products; further, morphology of all the samples has been authenticated from FESEM and TEM.     

Ethanol loading in an inductively coupled plasma

Changes to the fundamental and analytical parameters of a plasma have been investigated when ethanol has been added to aqueous or organic solutions. Excitation temperature, electron number density, and intensity of the H(alpha) line increased when ethanol has been added to aqueous solutions, while an electron density decrease and signal reduction have been found when ethanol has been added to xylene. The sensitivity has been improved for all ethanol concentrations when water has been the solvent, but the reverse has been found for xylene solutions.     

快原子轰击质谱及其在金属有机配合物研究中的应用

本文介绍FAB质谱的原理、功能和优点。综述了FAB机理,讨论了影响FAB谱的因素。归纳了FAB法在金属有机配合物研究中的应用。     

On temperature- and space-dimension dependent matter agglomerations in a mature growing stage

Model matter agglomerations, with temperature as leading control parameter, have been considered, and some of their characteristics have been studied. The primary interest has been focused on the grain volume fluctuations, the magnitude of which readily differentiates between two commonly encountered types of matter agglomeration/aggregation processes, observed roughly for high- and low-density matter organizations. The two distinguished types of matter arrangements have been described through the (entropic) potential driving the system. The impact of the potential type on the character of matter agglomeration has been studied, preferentially for (low-density) matter aggregation for which a logarithmic measure of its speed has been proposed. A common matter diffusion as well as mechanical relaxation picture, emerging during the mature growing stage, has been drawn using a phenomenological line of argumentation. Applications, mostly towards obtaining soft agglomerates or so-called jammed materials, have been mentioned.     

Theoretical Study of the AICI Disproportionation Reaction Mechanism on the Al(100) Surface

The surface disproportionation reaction mechanism of aluminum subchloride on the aluminum (100) surfaces has been investigated by the plane-wave density functional theory (DFT).Three kinds of possible reaction mechanism of AlCl disproportionation reaction on the aluminum (100)surfaces have been taken into account. The structures of reactants and products have been optimized, transition states have been confirmed and activation energies have been calculated. The adsorption energy of reactants and desorption energy of products have been determined. All of these have been employed to confirm the reaction mechanism and the rate determining step of AlCl disproportionation reaction on the aluminum (100) surfaces.     

Azacrownlactams Derived from Biphenyl. Study of Their Conformations, Complexation Ability and Electrochemical Behavior

Several macrolactams containing in their structure biphenyl and pyridine moieties have been synthesized. The complexation ability of these compounds has been evaluated and the results have been explained considering the existence of intramolecular hydrogen bonds. Conformational studies have been developed in some cases. Single-crystal X-ray diffraction studies have been carried out with one of the ligands. The electrochemical response of ligands 1 and 3 has been studied using cyclic and square wave voltammetry. The interaction of these ligands with Cu²⁺ ions in CH₃CN has been investigated by electrochemical techniques.     

Pt/HM、Pd/HM催化剂上CO氧化反应活性和动力学研究

研究了Pt/HM、Pd/HM催化剂上CO氧化反应的活性,求出了各种催化剂的CO氧化反应动力学方程。考察了不同气氛下CO氧化活性的演变规律和V⁴⁺、Co²⁺离子对Pt、Pd的助催化作用,并用催化剂集团结构适应模型对以上结果作出了解释。     

飞行时间二次离子质谱(TOF-SIMS)结合化学衍生法分析杂环新化合物的结构

飞行时间二次离子质谱(TOF-SIMS)分析了难挥发的杂环新化合物咪唑啉硫氰酸盐及其三种衍生物, 确认出很强的氢离化及银离化准分子离子峰, 通过对各种衍生物谱图的对照分析, 确认出较强的含有结构特征的碎片离子峰, 并对该化合物在离子轰击下的裂解规律作了分析, 支持了对该新化合物结构的鉴定。     

ClO与ClO自由基反应机理及电子密度拓扑分析

利用密度泛函理论对ClO与ClO自由基反应机理进行了深入理论探讨,在B3LYP/6-311＋＋G（3df）水平上对该反应体系的反应物、中间体、过渡态及产物进行了几何构型优化,对反应通道进行了IRC(内禀反应坐标）路径解析,计算了沿各反应通道的能垒和离解能,并进行了零点能校正.从量子拓扑学的角度,对反应通道IRC途径上一些重要点进行了电子密度拓扑分析,讨论了反应过程中化学键的断裂、生成以及键的变化规律,找到了反应途径的能量过渡态和结构过渡态.     

Determination of antioxidant migration levels from low-density polyethylene films into food simulants

An analytical method for the determination of specific migration levels of phenolic antioxidants from low-density polyethylene (LDPE) into food simulant has been developed. The screening and response surface experimental designs to optimize the liquid-liquid extraction (LLE) of these antioxidants have been tested and the analyses have been carried out by reversed-phase high-performance liquid chromatography (HPLC) coupled with ultraviolet diode-array detector. The procedure developed has been applied to specific migration tests in different commercial LDPE films. The considered antioxidants have not been found upper the legislation limits although Ethanox 330 and Irgafos 168 have been found at trace level.