新型色谱填料——石墨化碳黑

吉林炭素集团有限责任公司技术中心研究所是我国炭素行业最早的科研开发基地,拥有数名国家级炭素专家和高级研究人员。我所研制的新型色谱填料——ＳＴＨ系列石墨化碳黑在色谱分析中具有独特的分离效果,广泛应用于石油化工、食品卫生、医药卫生、环境保护和科研等方面,受到广大色谱工作者的重视和好评。该产品曾荣获吉林省优秀新产品奖、吉林省科技进步三等奖。产品使用性能达到国外的ＣａｒｂｏｐａｃｋＡ,Ｂ,Ｃ及ＳｔｅｒｌｉｎｇＦＴ牌号的石墨化碳黑水平,享誉国内外。ＳＴＨ系列石墨化碳黑出厂指标指　　标ＳＴＨⅠＳＴＨⅡ比…     

固相萃取-气相色谱/质谱结合保留指数检测卤水中有机物

建立了卤水中有机物的固相萃取-气相色谱/质谱(SPE-GC/MS)结合保留指数的分析方法.用石墨化碳黑柱对盐湖卤水中的有机物进行富集,采用GC-MS,以扫描离子检测模式(SCAN),选择离子检测模式(SIM)和保留指数法进行检测.考察了样品的pH值、洗脱剂种类、洗脱剂用量等因素,并对实验条件进行了优化.同时采用氘标记化...     

多壁碳纳米管作为气相色谱固定相的性能研究

将甲烷催化裂解法生产的经过纯化的多壁碳纳米管(PMWCNTs)、活性炭、石墨 化碳黑(Carbopack B)分别填装成气相色谱填充柱,比较它们分离烷烃、芳香烃、 卤代烃、醇、酮、醚、酯类的性能。分别在PMWCNTs和Carbopack B上涂清5%(w/w) 的Carbowax 20M,填装成气相色谱填充柱后,比较它们分离醇、酮、醚、酯、有机 酸类的性能。结果表明,PMWCNTs是一种性能优异的气相色谱固定相。与相同比表 面积的Carbopack B石墨化碳黑相比较,它有更强的保留能力,适合于分析沸点相 对较低的化合物;具有更均匀的表面,表现为极性化合物亦可得到对称的峰形;理 论塔板数较小。此外,和Carbopack B一样,PMWCNTs涂清5% (w/w) Carbowax 20M 后可用来分离极性化合物,甚至是强极性的小分子有机酸。     

在线净化加速溶剂萃取–气相色谱–质谱法测定土壤中11种半挥发性有机物

采用加速溶剂萃取法对样品进行在线净化和萃取,气相色谱–质谱法测定土壤中11种半挥发性有机物.考察了净化条件、萃取剂、浓缩条件等因素对土壤中11种半挥发性有机物测定的影响,分析了在线净化和离线净化的差异以及在线净化的优势.以弗罗里硅土和石墨化碳黑为净化剂,石英砂为分散剂,土壤样品经快速溶剂萃取仪在线净化萃取,浓缩后采用气...     

四氧化三铁负载石墨化碳黑磁性纳米材料的制备及其在茶叶中多种农药残留检测中的应用

基于物理共混法制备了一种均匀的四氧化三铁负载石墨化碳黑磁性纳米材料(GCB/Fe3O4).以此为固相萃取吸附剂,建立了酚钙共沉淀-磁性固相萃取-气相色谱/三重四极杆串联质谱技术(GC-MS/MS)同时测定茶叶中405种农药残留的分析方法.对GCB/Fe3O4的晶体结构、表面形貌以及吸附色素的能力进行了探讨.结果 表明,...     

气相色谱–串联质谱法测定中药材中35种农药残留的样品处理方法

分析对比气相色谱–串联质谱(GC–MS/MS)法测定中药材中35种农药残留的3种样品处理方法,为中药材中农药残留检测提供参考.以乙腈为提取溶剂,样品经高速匀浆提取后,取提取液进行净化处理.比较了基于QuEChERS原则的处理方法、石墨化碳黑–氨基复合固相萃取(GCB–NH2)法和亲水亲油平衡材料固相萃取(HLB)法3种...     

超高效液相色谱-串联质谱法测定人参、黄芪中多种除草剂残留量

建立了人参和黄芪中55种除草剂残留量的超高效液相色谱-串联质谱检测方法.样品中残留的药物经乙腈提取,石墨化碳黑固相萃取柱净化,甲醇-二氯甲烷洗脱,最后采用电喷雾串联质谱在正离子多反应监测模式下进行测定.55种农药的检测限和定量限分别为0.4 ～20 μg/kg和2～100 μg/kg.在各自的浓度范围内,55种药剂的线...     

二维气相色谱在微量分析中的应用

 〕为探索溶剂或单体中微量杂质分析方法，在SP-2305E型色谱仪上设计了二维气相色谱流程，采用在线微型六通阀进行流路切换，用微型中间陷阱进行“再进样”。用自制石墨化碳黑毛细管柱和不同极性的填充预柱，对氯甲烷中微量杂质进行了分离和定性。     

石墨炔类结构储锂性能的第一性原理研究

基于密度泛函理论的第一性原理的计算方法, 研究了石墨炔类结构的储锂性能, 结果表明, 石墨炔类体系是一种理想的储锂材料, 锂原子通过向衬底转移电荷而带正电, 彼此之间的库仑排斥作用避免了锂原子的团簇化. 通过比较石墨一炔到石墨五炔的储锂性能, 发现并不是炔键越多其储锂性能就越好, 还需考虑炔键的增多对结构稳定性的影响. 在保证石墨炔类结构稳定的前提下, 石墨二炔和石墨五炔达到LiC₃的最大储锂量.     

纺织品与食品包装材料中烷基酚及双酚A迁移量的液相色谱-串联质谱分析

建立了纺织品与食品包装材料中烷基酚及双酚A迁移量的液相色谱-串联质谱分析方法.纺织品和食品包装材料浸泡液经Supelclean Envi-Carb石墨化碳黑固相萃取柱净化,以Waters XBridge C_(18)(150 mm×2.1 mm,3.5 μm)色谱柱分离后,进行LC-MS/MS多反应监测模式下的定性及定量分析.烷基酚和双酚A在纺织品模拟汗液、食品模拟物介质中特定迁移量的定量下限分别为2、4 μg/kg.在低、中、高3个添加水平下,测得纺织品样品的回收率为83%～91%,相对标准偏差为4.1%～9.0%;食品包装材料样品的回收率为82%～94%,相对标准偏差为3.9%～8.7%.     

The selectivity and polarity of carbon layer open tubular capillary columns modified with a polar liquid phase

The polarity of carbon layer open tubular (CLOT) columns coated with a layer of non-porous graphitized carbon black (Carbopack B) modified with an appropriate amount of polar polyglycol liquid phase has been evaluated and compared with that of standard polar (Supelcowax-10) and non-polar (SPB-1) bonded phase open tubular columns. The efficiency and selectivity were measured at various temperatures and the polarity of the columns was evaluated by use of McReynolds' constants and the difference in apparent carbon number, ΔC of linear alkanes and alcohols. The polarity of the CLOT column was found to depend on temperature, and changing the analytical conditions therefore enabled the separation of compounds of different polarity whose reciprocal position and resolution were affected by temperature. The application of calculation methods which enable programmed temperature retention times to be predicted from isothermal data was also found to be possible when the polarity of the CLOT column changes with temperature.     

Comparison of column properties in reversed-phase chromatography: monolithic, cholesterolic and mixed bonded stationary phases

A commercial Chromolith C18 column and two new stationary phases with mixed ligands bonded on the Kromasil silica gel support, SG-MIX and SG-Chol, were characterized using simple tests based on the retention of non-polar, basic and acidic compounds. Polar and methylene selectivity tests in acetonitrile-water and methanol-water mobile phases revealed lower hydrophobicities of the SG-MIX and SG-Chol columns in comparison to the Chromolith column. The columns were further characterized using new test criteria - gradient oligomer capacity and isomeric selectivity and peak symmetry of naphthalene di-sulphonic acids in aqueous mobile phases. The cholesterolic column shows greater gradient oligomer selectivity for the separation of oligoethylene glycol samples than the SG-MIX and the Chromolith columns. Increased retention and peak tailing, but decreased isomeric selectivity for naphthalene-di-sulphonic acids was observed with the SG-MIX column, because of interactions with various polar bonded groups.     

Evaluation of multi-walled carbon nanotubes as gas chromatographic column packing

Purified multi-walled carbon nanotubes (PMWCNTs), activated charcoal and graphitized carbon black (Carbopack B) were used as column packing materials to compare their separation ability and other gas chromatographic behavior for aromatic hydrocarbons, alkanes, halogenated hydrocarbons, alcohols, ketones, esters, and ethers. The results show that PMWCNTs can be an excellent gas chromatographic packing material. Compared to Carbopack B with the same surface area, PMWCNTs had a stronger retention ability, a more homogenous surface and smaller theoretical plate numbers. Polar compounds can present symmetric peaks on PMWCNTs. PMWCNTs were found to be an interesting alternative adsorbent to activated charcoal and Carbopack B as gas chromatographic column packing material for volatile compounds, especially those with relatively low boiling points.     

Novel reversed-phase high-performance liquid chromatography stationary phase with oligo(ethylene glycol) "click" to silica

Oligo(ethylene glycol) (OEG) covalently bonded silica was prepared by using click chemistry and employed as a stationary phase for reversed-phase high-performance liquid chromatography. The column efficiency and effect of organic modifier content on retention were investigated. The separation selectivity was also studied with phenyl compounds and an actual sample of natural products. The results indicated that the stationary phase possessed good separation efficiency and separation selectivity in RP-HPLC mode. Moreover, the stationary phase showed good complementary separation selectivity to the C18 stationary phase. The OEG stationary phase had "clustering" function for "homologous component" in the separation of natural products.     

Ionic liquid‐bonded polysiloxane as stationary phase for capillary gas chromatography

Ionic liquid (IL) stationary phase is especially suitable for separation of complex samples, owing to the “dual nature” of IL. In this study, a synthetic method of ionic liquid‐bonded polysiloxane (PSOIL) as stationary phase of GC was proposed. Then, the PSOIL was used to prepare an 8 m capillary column by static method. The column efficiency was measured to be about 4000 plates/m (k=3.55, naphthalene) after the column had been conditioned at 210°C. The durability of PSOIL column was better than that of the mixed stationary phase of IL and OV‐1. Moreover, the Abraham solvation parameter model was employed to characterize the PSOIL. The result revealed that the PSOIL had stronger dispersion force (l) than neat IL and stronger hydrogen bond basicity (a) than DB‐1. That meant the PSOIL might offer good selectivity for both polar and non‐polar analytes. The column exhibited unique selectivity for various organic substances, such as the homologous compounds of alkanes, esters, alcohols and aromatic compounds. It was also found that some aromatic positional isomers could be separated better on the PSOIL column than on the DB‐1 column. Furthermore, the stationary phase was suitable for separation of high‐boiling point compounds such as polycyclic aromatic hydrocarbons, phthalic esters, etc. All of these demonstrated that the PSOIL offered good selectivity and high separation efficiency for a wide range of analytes.     

Bonded Cyclodextrin Stationary Phase Columns for the Separation of Cis/Trans Cyclohexane Derivatives

Abstract

Cyclohexane derivatives are important in the manufacture of monomers for the preparation of polyester polymers. The separation of cis/trans isomers of these derivatives has been investigated by using a bonded cyclodextrin column. This stationary phase offers excellent selectivity for the separation of these compounds. Although the efficiency of this column with the cyclohexane derivatives is less than the efficiency with nitroanalines, its excellent selectivity enabled adequate separation of the isomers of all but one of the compounds studied. A strategy for enhancing the efficiency and selectivity of this stationary phase is presented.     

Impurities Released from Extractive Phases Used in the Analysis of Pesticides

Abstract

Elution fractions relative to solid phase extraction (SPE) procedures using C-18 bonded silica and Carbopack B columns plus C-18 membranes have been analyzed by gas chromatography-mass spectrometry (GC-MS) for the characterization of interfering compounds from the phases. Alkanes, alkenes, phthalates and some silyl compounds (silanols, siloxanes) have been tentatively identified. Experiments on commercial C-18 phases prepacked in plastic tubes show that the increased interference compared to the phases alone comes from the polymer container. N-butylbenzensulfonamide (NBBSA) was identified as causing interference when the extraction device used for SPE involved plastic components. Increasing amounts of silanol interferences released from the C-18 phases were observed after passage of the water sample, depending on the acidic pH, as evidence of the hydrolysis of the bonded silica.     

Chitosan-silica hybrid-coated open tubular column for hydrophilic interaction capillary electrochromatography

A novel and convenient protocol for the preparation of an open-tubular column coated with chitosan-silica hybrid using chitosan and silane-coupling agent (γ-glycidoxy-propyltrimethoxysilane) was developed for CEC, in which, chitosan was covalently bonded to the inner wall of a fused-silica capillary using γ-glycidoxy-propyltrimethoxysilane as a cross-linking agent. The stationary phase was hydrophilic due to the chitosan-silica hybrid with abundant amine and hydroxyl functional groups. The chromatographic characteristics of the column were evaluated by the separation of some organic acids and inorganic anions. The column showed good selectivity for nucleotides, aromatic acids, and inorganic anions. The mechanism for the separation of these compounds was primarily based on the hydrophilic and electrostatic interactions combined with the electrophoretic mechanism. The CEC method on the column for the separation of these compounds was compared with CE method in a bare capillary.     

Superheated water as eluent in high-temperature high-performance liquid chromatographic separations of steroids on a polymer-coated zirconia column

High-temperature liquid chromatography (HTLC), with a superheated water mobile phase, has been shown to be a feasible replacement for medium-polarity acetonitrile-water mixtures as an eluent in reversed-phase HPLC. Instrumental parameters of flow-rate, injection volume and mobile phase preheating were shown to have significant effects on the quality of the chromatographic peaks. The selectivity and retention patterns of testosterone and several related compounds were investigated on a porous zirconia, polybutadiene-coated column at temperatures up to 200 degrees C and compared with that of a porous silica, octadecylsilane-coated column and the zirconia column under traditional reversed-phase conditions of an acetonitrile-water mobile phase at 40 degrees C. The selectivity differences observed for testosterone and related compounds show that the separation mechanisms are complementary and unique selectivity is obtained with the zirconia column under HTLC conditions.