毛细管电泳-电感耦合等离子质谱联用的接口设计

描述了毛细管电泳电感耦合等离子体质谱(CE-ICP-MS)联用技术的单T型接口,自行设计了双T型接口,并对两接口的分析性能作了比较。解决了接口中的常见问题,使用节流阀减小自吸作用并降低了CE分离物的稀释倍数,排气阀使提升量保持稳定。经考察得知,采用自吸作用提升液流流量稳定,其重现性RSD小于5％;双T型接口较单T型接口对CE分离更有利。采用双T型接口联用时,CE分离La、Ce、Nd混合离子迁移时间RSD小于2％,MS信号RSD小于15％,且不同浓度样品经CE分离后其MS信号基本呈线性关系。     

Rapid QuEChERS Approach Using Novel Solid Phase Extraction for Insecticides in Lobster and Shellfish Tissue with Gas Chromatography–Tandem Mass Spectrometry

Novel, rapid, inexpensive, and simple QuEChERS extraction followed by phospholipid solid phase extraction was successfully developed and validated for the determination of methoprene, resmethrin, bifenthrin, cyhalothrin, and permethrin in lobster and shellfish tissues by gas chromatography–tandem mass spectrometry. This method is equivalent in final sample purity to the traditional gel permeation and open column chromatography sample preparation techniques, but has clear advantages due to reductions in time, labor, solvent use, and can be performed with minimal staff training. The proposed methodology was effectively applied to the analysis of North Atlantic lobster (hepatopancreas and muscle) and shellfish tissue. The linearity of the calibration curves for all analytes were R² > 0.9991. The surrogate recoveries were 98.2 ± 18.0%, while the target compound recoveries, for fortified samples, were in the range of 62.0%–128.8% with RSD values <17.2% for all compounds. The detection limits for the analytes ranged from 0.0056 µg/g to 0.76 µg/g with 84.4–119.5% accuracy and relative standard deviations less than 3.77%.     

甲氧滴涕原药成分的气相色谱和气相色谱-质谱分析

本文用气相色谱（GC），气相色谱-质谱联用（GC－MS）测定了甲氧滴涕（DMDT）原药中有效成分的含量及11种成分的结构。GC法内标定量结果表明，产品甲氧滴涕原药中有效成份达90％以上。     

Simplification of Ink Dating for Forensic Analysis by Thermal Microdesorption Gas Chromatography–Mass Spectrometry

A simplified procedure for obtaining measurements useful for ink dating is presented for forensic analysis. A thermal microdesorption device was employed with gas chromatography–mass spectrometry (GC-MS). The release of phenoxyethanol from the ink entries on paper was studied at several temperatures during a single analysis. A separate thermal desorption unit was not required. Two methods measuring the amount of phenoxyethanol liberated at four temperatures and two temperatures were proposed. The effect of heating of ink samples to 70?°C for 30?minutes applied to fresh and old samples was studied. An illustration how to distinguish between fresh and old samples by the analysis of the same ink entry after the time period of two months is provided.     

A Comparison of Some Derivatives of Primary Amines for Gas Chromatography Using Electron Capture Detection

Abstract

Thirteen derivatives of phenethylamine were prepared. The sensitivities of flame ionization and electron capture detectors to these compounds and the original amine were determined. All compounds showed approximately the same sensitivity of detection with a flame ionization detector, but with an electron capture detector there was a 2 × 10⁵ difference in sensitivity of detection between the derivatives showing the greatest and the least sensitivity. The derivative with the greatest sensitivity of detection was the pentafluorobenzaldehyde-amine condensation product and amounts of the amine down to 10 picograms could easily be quantified.     

Conformation‐Specific Circular Dichroism Spectroscopy of Cold,Isolated Chiral Molecules

The CD spectroscopy of a chiral compound in solution yields an average CD value derived from all of the conformations of a chiral molecule. By contrast, CD spectroscopy of cold chiral molecules in the gas phase distinguishes specific conformers of a chiral molecule, but the weak CD effect has limited the practical application of this technique. Reported herein is the first resonant two‐photon ionization CD spectra of ephedrines in a supersonic jet using circularly polarized laser pulses, which were generated by synchronizing the oscillation of the photoelastic modulator with the laser firing. The spectra exhibited well‐resolved CD bands which were specific for the conformations and vibrational modes of each enantiomer. The CD signs and magnitudes of the jet‐cooled chiral molecules were very sensitive to their conformations and thus offered crucial information for determining the three‐dimensional structures of chiral species, as conducted in combination with quantum chemical calculations.     

Testosterone Heptafluorobutyrates: Derivatives for Gas Chromatography

Abstract

The reaction of testosterone with heptafluorobutyric anhydride, in the presence of pyridine or collidine, leads to two diheptafluorobutyrate (HFB) derivatives. These compounds are believed to be the di-HFB esters of 2,4-androstadien-3, 17β-diol (A) and 3, 5-androstadien-3, 17β-diol (B), with A as the major product. This is similar to the reaction with silylating reagents which leads to two isomeric enol ethers. In benzene or acetone solution, and in the absence of an organic base, the same two isomers are formed, but with B as the major product. Although the latter reaction has been recommended for quantitative work, the formation of isomeric enol esters has not been noted. Since the products are not stable in the reaction medium, the method is not entirely satisfactory. The reaction in pyridine solution should be suitable for quantitative work; the products are stable in solution and can be detected in subnanogram amounts.     

食品中胆固醇色谱／质谱／质谱的测定

确立了用色谱／质谱／质谱测定食品中胆固醇的一种新方法，试样经乙酸乙酯提取后，ＧＣ／ＭＳ／ＭＳ测定分析，以胆固醇分子离子为母离了，以其子离子为定量分析的碎片离子。线性好，回收率高，方法可靠。     

Coupling Pervaporation-Gas Chromatography for Speciation of Volatile Forms of Selenium in Sediments

Abstract

A method for speciation of dimethylselenide (DMeSe), dimethyldiselenide (DMeDSe) and diethylselenide (DEtSe) in sediments based on a coupling between a pervaporation module, a preconcentration sorptive trap and a gas chromatograph-mass spectrometer is reported. The coupling is performed through a high pressure injection valve which allows two different operational modes: (a) analysis without preconcentration, in which analytes are directly driven from the pervaporation chamber to the injection port of the chromatograph, and (b) analysis with preconcentration in a trap, in which the analytes from the pervaporation chamber are first trapped on a Tenax minicolumn and then thermally desorbed and driven to the GC. This second approach improves the sensitivity compared to the direct coupling, reaching estimated absolute detection limits lower than 0.6 ng Se for each tested species. The method is applied to the determination of volatile organic selenium species in several sediments collected from different areas in the Southwest of Spain.     

电喷雾离子化接口及其在毛细管电泳／质谱法中的应用

论述了ＥＳＩ的工作原理，结构和ＣＥ－ＥＳＩ－ＭＳ的应用。     

粒子束接口液相色谱－质谱应用

粒子束接口液相色谱－质谱应用黄峰（山东大学发酵工程国家实验室济南２５０１００）１前言化学和生物样品中的热不稳定性组分及难挥发性组分无法用气相色谱。质谱进行分析，因此液相色谱。质谱联用倍受关注。近二十年来发展了许多技术，如直接液体导入（ｄｉｒｅｃｔｌｉ...     

Infrared Spectroscopy of Neutral and Cationic Pyrrolidine Monomer in Supersonic Jet

Pyrrolidine, a five membered heterocyclic molecule, is widely existing in organism. Herein, infrared spectra of pyrrolidine monomer in neutral and cationic states were obtained by vacuum ultraviolet ionization, infrared photodissociation and time of flight mass spectrometry. Both in neutral and cationic states, it is found that their CH stretching vibration bands are red shifted. In the IR spectrum of neutral pyrrolidine, because the electric dipole moment of NH is small, we have not observed the NH stretching vibration bands. However, the NH stretching vibration band of pyrrolidine is greatly enhanced after ionization, and this band red-shifts compared with the previous experiment. The red shifts of CH stretching vibrations in neutral and cationic states are caused by the negative and positive hyperconjugation, respectively. The enhancement and red shift of the NH stretching band are owing to the ejection of the electrons on the N atom after ionization. Through the calculations, it is found that the acidity of the CH bond is a little stronger than that of NH bond. These kinds of studies would be helpful to understand the intrinsic properties of biomolecules in neutral and cationic states, and to provide reference for the further study of living organic macromolecules.     

Laser Spectroscopy and Lifetime Measurements of the S1 State of Tetracyanoquinodimethane (TCNQ) in a Cold Gas-Phase Free-Jet

The S₁ electronic state of 7,7,8,8-Tetracyanoquinodimethane (TCNQ) has been investigated by laser induced fluorescence (LIF), dispersed fluorescence (DF) spectroscopy, and lifetime measurements under jet-cooled conditions in the gas-phase. The LIF spectrum showed a weak origin band at 412.13 nm (24262 cm⁻¹) with prominent progression and combination bands involving vibrations of 327, 1098, and 2430 cm⁻¹. In addition, very strong bands appeared at ∼363.6 nm (3300 cm⁻¹ above the origin). Both the LIF and DF spectra indicate considerable geometric change in the S₁ state. The fluorescence lifetime of S₁ at zero-point level was obtained to be 220 ns. This lifetime is 40 times longer than the radiative lifetime estimated from the S₁−S₀ oscillator strength. Furthermore, the lifetimes of the vibronic bands exhibited drastic energy dependence, indicating a strong mixing with the triplet (T₁) or intramolecular charge-transfer (CT) state. This study is thought to disclose intrinsic nature of TCNQ, which has been well known as a component of organic semiconductors and a versatile p-type dopant.     

粮谷和油籽中丰索磷残留量的气相色谱及气相色谱／质谱分析

介绍应用气相色谱和气相色谱－质谱法测定及确证粮谷和油籽中丰索磷的残留含量，试样采用水－丙酮提取，提取液经液－液分配后，再以弗罗里硅土柱净化，气相色谱，火焰光度检测器测定，外标法定量，并用气相色谱－质谱针对丰索磷的选择监测离子的种类和丰度比进行敢阳性确证。     

凝胶渗透色谱净化-气相色谱/串联质谱分析蘑菇中的36种农药残留

建立了用凝胶渗透色谱净化-气相色谱/串联质谱分析蘑菇中36种农药残留的方法。蘑菇中的待测农药组分在30 ℃条件下用乙酸乙酯提取,高速匀浆后通过凝胶渗透色谱净化;选用填料为中性多孔的聚苯乙烯二乙烯基苯微球体的S-X3玻璃柱(22 g,19 cm×2 cm)作为凝胶渗透色谱净化柱,流动相为乙酸乙酯-环己烷(体积比为1∶1)溶液,流速5 mL/min;收集第7~15 min流出的液体用气相色谱-三重四极杆串联质谱仪测定。在0.01~1.0 mg/L的质量浓度范围内,各种农药标准溶液的线性相关系数均大于0.99。在样品中添加36种农药(添加水平为0.01,0.05,0.10 mg/kg)的混合标准溶液,平均回收率为72.6%~117.1%,相对标准偏差为2.0%~10.8%(n=5),最低检出限为 0.1~0.7 μg/kg,最低定量限为 0.2~2 μg/kg。     

甲基安非他明及杂质的气相色谱／质谱分析

利用ＤＢ－５弹性石英毛细管柱气相色谱／质谱联用技术分析公安人员缴获非法生产甲基安非他明粗产品，其中含有甲基安非他明８３％，及主要杂质１－苯基丙酮１３．３６％和２－甲亚胺基－１－基基丙烷１．３３％。此外还检测到 了甲基安非他明的分解产物１－丙烯基苯０．１１％、２－丙烯基苯０．０３％和环丙基苯０．０１％等。据此我科可以判断，该甲基安非他明是从１－苯基丙酮和甲胺反应再经催化氢化合而得。     

A New Dimension in Separation Science: Comprehensive Two‐Dimensional Gas Chromatography

The introduction and development of comprehensive two‐dimensional gas chromatography offers greatly enhanced resolution and identification of organic analytes in complex mixtures compared to any one‐dimensional separation technique. Initially promoted by the need to resolve highly complex petroleum samples, the technique’s enormous separation power and enhanced ability to gather information has rapidly attracted the attention of analysts from all scientific fields. In this Minireview, we highlight the fundamental theory, recent advances, and future trends in the instrumentation and application of comprehensive two‐dimensional column separation.