Analysis of cannabinoids by liquid chromatography— Thermospray mass spectrometry and liquid chromatography— Tandem mass spectrometry

Summary A rapid method based on liquid chromatography and thermospray mass spectrometry without any derivatization or pre-purification steps has been developed for the identification and quantification of cannabinoids in drugs from cannabis plants. The extracts were separated on a C₁₈ reversed-phase column with an acidic acetonitrile-water gradient. Liquid chromatographymass spectrometry was performed with a thermospray interface and protonated molecular ions were obtained from the cannabinoids of interest. Liquid chromatography-tandem mass spectrometry experiments on the molecular ions gave additional structural information online. The sensitivity and selectivity of the method was sufficient to enable the detection of 100 pg of the cannabinoids.     

Thermal mobilization of hydrocarbons from small-size rock samples. Application in petroleum geochemistry

Summary The quantitative analysis of hydrocarbons (C₁ to C₁₅ molecular range) from the water saturated pore structure of sedimentary rocks is performed by a combined thermal mobilization/glass capillary GC system. Organic geochemical processes, such as the generation of hydrocarbons as a function of kerogen type and maturity of sedimentary organic matter are studied.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Automatic headspace gas chromatography of C1–C7 hydrocarbons in sedimentary rocks. Application in Petroleum Geochemistry

Summary The analysis of hydrocarbons (C₁–C₇ molecular range) from the water-saturated pore structure of sedimentary rocks is performed by headspace gas chromatography. Hydrocarbon yields are compared to those of dynamic gas extraction techniques (gas stripping, thermovapourization). Lowest detectable quantity is estimated as 1–10 ppb (w/w) for the C₁–C₅ molecular range. Automation of the method helps to improve its application for routine light-hydrocarbon analysis in rock samples of oil and gas exploration wells. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

气相色谱-三重四极杆串联质谱法检测环境空气中的多环芳烃

建立了气相色谱-三重四极杆串联质谱检测环境空气中多环芳烃的方法,并利用同位素稀释法对多环芳烃进行了测定。将该方法应用于华南地区某大型石化企业周边环境空气中多环芳烃的检测,并与气相色谱-质谱方法进行了对比。结果表明,该方法的仪器检出限（0.01~0.15 μg/L）和定量限（0.03~1.5 μg/L）均优于气相色谱-质谱法（0.1~0.8 μg/L和0.3~3.5 μg/L）,并有更好的灵敏度与选择性。当利用气相色谱-质谱作为检测手段时,回收率指示物氘代菲和进样内标六甲基苯均受到了杂质的严重干扰,影响了定量结果的准确性,而三重四极杆串联质谱很好地解决了这些问题。实际样品分析时,标准曲线中16种多环芳烃相对响应因子的相对标准偏差为2.60%~15.6%,氘代化合物的回收率为55.2%~82.3%,空白加标样品的回收率为98.9%~111%,平行样品的相对标准偏差为6.50%~18.4%,采样空白含量范围为未检出~44.3 pg/m³,实验室空白含量范围为未检出~36.5 pg/m³。上述研究表明,分析环境空气中的多环芳烃时,气相色谱-三重四极杆串联质谱方法值得推广。     

Characterization of sixty alkenes in a cat-cracked gasoline naphtha by gas chromatography

Summary The alkene-rich petrol fraction from refinery fluid catalytic cracking (FCC) has been characterized by GC and GC-MS. Quantitative proportions and retention data of 52 acyclic and 11 cyclic C₅–C₇ alkenes are given. Relative retentions are reported for methylsilicone and aluminium oxide stationary phases as methylene units (MU). Applications of mass spectra, single-ion GC-MS monitoring and retention data for identifications are demonstrated.     

Magnetic solid-phase extraction based on octadecyl functionalization of monodisperse magnetic ferrite microspheres for the determination of polycyclic aromatic hydrocarbons in aqueous samples coupled with gas chromatography-mass spectrometry

Monodisperse magnetic C₁₈ microspheres were prepared based on the three-step reactions of solvothermal reduction, silanization and alkylation. The microspheres are of uniform sizes in the range of 200-260 nm. The structure of synthesized magnetic C₁₈ microspheres was studied by transmission electron microscopy, scanning electron microscopy, X-ray diffraction patterns, element analysis and vibrating sample magnetometry. This material has a high magnetic saturation value of 59 emu g⁻¹ and is easy to manipulate under a magnet. The prepared material was used for the preconcentration of the polycyclic aromatic hydrocarbon in water. The effects of desorption solvent and the amount of adsorbent on the preconcentration were also investigated. The results showed that the developed method was beneficial for the preconcentration of PAHs of middle molecular weight.     

假蒟挥发油化学成分气质联用分析研究

采用常规水蒸气蒸馏法提取出假岛精油,经气相色谱-质谱联机分析,分出60多个峰,鉴定出67种化合物,它们主要是2,4,5-三甲氧基-1-丙烯基苯3．20％）,顺-石竹烯（13．33％）,1,2-二甲氧基-4-（1-丙烯基）苯（12．63％）,细辛（9．94％）,4-甲氧基-6-（2-丙烯基）-1,3-苯并二恶茂（5．71％）,δ-杜松烯（3．03％）etc,占总峰面积的67．84％。     

凝胶渗透色谱净化-气质联用法测定土壤中三嗪类除草剂

建立了以超声波提取、凝胶渗透色谱净化(GPC)、HP-5 MS石英毛细管柱分离、E1离子源质谱法测定土壤中13种三嗪类除草剂的多残留检测方法.三嗪类除草剂的添加水平为0.010～0.100 mg/kg时,平均回收率为72.1%～118.3%,相对标准偏差为2.6%～19.8%(n=4);方法的检出限为0.30～2.50μg/kg.     

浓缩苹果汁中多种拟除虫菊酯类农药残留量的气相色谱-质谱测定方法

采用固相萃取技术,以丙酮和正己烷提取,C18小柱净化,用GC MS可同时测定浓缩苹果汁中4种拟除虫菊酯类农药的残留量。方法的回收率在96.5%～111.9%之间,相对标准偏差为1.7%～6.9%,最低检测浓度在0.02～0.10μg kg之间。     

凝胶渗透色谱-气相色谱-质谱测定花生中乙草胺的残留量

建立了以凝胶渗透色谱(GPC)净化和气相色谱-质谱(GC-MS)技术快速测定花生中乙草胺残留量的方法.经乙腈提取,共提物中的油脂和色素经GPC去除,目标农药采用GC-MS-SIM方式进行定性和定量分析.方法的回收率90%～120%;相对标准偏差2.5%～10%.方法定量限0.005 μg/g.     

Determination of cyclo C6 and C7 peroxides and hydroperoxides by gas chromatography

Summary A method for determining cyclo C₆-C₇-peroxides and hydroperoxides by high-resolution capillary GC has been developed. The compounds were synthesized in the liquid phase and identified in chromatograms of the reaction mixture of cyclohexyl hydroperoxide and cycloheptane using GC-MS. Peroxy compounds were determined using an FID. The effective carbon number (ECN) concept was used to calculate response factors of the peroxy compounds analysed. The experimentally determined response factor for cyclohexyl hydroperoxide was identical (within error limits) with that calculated.     

Quantification of total petrol hydrocarbons (TPH) in soil by IR-spectrometry and gas chromatography – conclusions from three proficiency testing rounds

Due to the utilisation of 1,1,2-trichlorotrifluoroethane (CFE) as extraction solvent the IR-spectrometric determination of total petrol hydrocarbon (TPH) in soil according to ISO/TR 11046 has been replaced by gas chromatography/flame ionisation detection (GC/FID) after extraction with a halogen-free solvent according to ISO/DIS 16703:2001. The results obtained with both methods by field laboratories in three proficiency testing (PT) rounds are compared. The consensus means obtained with GC/FID are typically 10%–20% (ranging between 0% and 25%) higher than those found with IR-spectroscopy. On the contrary, coefficients of variation (CV) are roughly double in case of GC/FID and are briefly discussed against the background of the Horwitz equation. Received: 19 November 2001 Accepted: 17 March 2002     

Analysis of organic solvents in printing inks by headspace gas chromatography – mass spectrometry

Static headspace analysis by gas chromatography has been found to be a suitable method for the analysis of organic solvents in printing inks. Experimental conditions for the analysis have been optimized, and the accuracy and relative standard deviation of the method has been determined. The solvent content of 29 printing inks has been measured.     

Integrated analysis of serum and liver metabonome in liver transplanted rats by gas chromatography coupled with mass spectrometry

In this paper, we present a metabonomic method for the investigation of abnormal metabolic process in both serum and liver tissue of liver transplanted rats. Syngeneic transplantation was performed on male Lewis rats. The serum and grafted liver on day 1, 3, and 7 post-transplant were collected to analyze endogenous metabolites using gas chromatography coupled with mass spectrometry (GC-MS). The method was validated with acceptable linearity, precision, and repeatability. Thirty-four metabolites in serum and 29 metabolites in liver were identified. Results of correlation analysis illustrated metabolites with similar function exhibited similar variations in liver and serum. The data processed by principle component analysis (PCA) showed time-dependent biochemical variations. As a consequence, the present study may offer specific putative pathways in the pathophysiological mechanism of orthotopic liver transplantation.     

Separation of mixtures of permanent gases and light hydrocarbons on spherical carbon molecular sieves by gas-solid chromatography

Summary Experimental results are presented on the application of Carbosieve S (Supelco) and Spherocarb (Analabs) spherical carbon molecular sieves for the gas chromatographic separation of mixtures of permanent gases and C₁–C₃ hydrocarbons using a single column or two columns in series. At a programmed temperature of 35–300°C, good separation of the sample components was obtained when using helium as the carrier gas. When hydrogen was used as the carrier gas and the analysis was carried out under isothermal conditions the elution sequence of oxygen and nitrogen reversed as the temperature was increased. This behaviour was observed within a temperature range of 35–225°C for Carbosieve S, and within a temperature range of 35–300°C for Spherocarb.     

Identification of oxygenated polycyclic aromatic hydrocarbons in diesel particulate matter by capillary gas chromatography and capillary gas chromatography/mass spectrometry

Summary Using a two-step liquid chromatographic separation on normalphase cartridges, crude extracts of diesel particulate matter can be separated without time-consuming sample handling into special fractions which mainly contain slightly-polar oxygenated polycyclic aromatic hydrocarbons (oxy-PAH) and nitrated polycyclic aromatic hydrocarbons (nitro-PAH). Subsequent analysis was by fused-silica capillary gas chromatography on a SE54 column along with flame-ionisation (GC/FID) and positive-ion electron-impact mass spectrometric detection (GC/MS) respectively. A number of individual oxy-PAH belonging to four different chemical classes (ketones, quinones, anhydrides and aldehydes) and several individual nitro-PAH were characterized by their retention times and mass spectra. Presented at the 15th International Symposium on Chromatography, Nürnberg, October 1984     

Determination of triazine herbicides in surface and drinking waters by off-line combination of liquid chromatography and gas chromatography-mass spectrometry

Summary Mass spectra of 12 triazines were obtained by electron impact (EI), positive-ion chemical ionization (PCI) and negative-ion chemical ionization (NCI) using methane and isobutane as reagent gases. EI mass spectrometry is more sensitive than PCI and NCI, although the chemical ionization modes increase selectivity markedly. A pre-column packed with polymer stationary phase was employed to preconcentrate surface and drinking water samples. After desorption of the analytes with ethyl acetate, an aliquot was injected directly into the GC-MS system. Atrazine and simizine were found in these samples at 10–80 ppt levels. The limits of detection for both herbicides were below 10 ppt in drinking water.     

溶剂转移-气相色谱-质谱法和选择洗脱-气相色谱法测定大蒜中289种农药多残留

以溶剂转移净化为核心步骤,建立了一种适用于大蒜样品中农药多残留分析的前处理方法(方法I),配以一个辅助方法(方法II),构成大蒜中常见289种农药多残留的分析体系(方法I283种,方法II6种)。方法I中,样品用乙腈-水溶液提取,盐析分配,溶剂转移和固相萃取(SPE)净化后进行气相色谱-质谱(GC-MS)分析;方法II中,样品用无水Na2SO4配合乙酸乙酯均质研磨,超声波辅助提取,提取液经Primary Secondary Amine (PSA)粉末分散固相萃取和LC-Si柱选择洗脱净化后进行GC分析。GC-MS采用选择离子监测(SIM)方式,GC采用火焰光度检测器(FPD)检测,外标法定量。方法简便、快速,通过优化前处理和上机条件,在最优条件下进行测试,方法的定量限(S/N≥10)为0.01～0.05 mg/kg。方法I中,在加标水平为0.02、0.20 mg/kg时,回收率为52%～163%,其中回收率在70%～120%之间的占88%,相对标准偏差为2.4%～18%;方法II中,在加标水平为0.01、0.02、0.10、0.20 mg/kg时,回收率为70%～111%,相对标准偏差为3.2%～9.3%。详细描述了实验模型的构建,并对GC-MS灵敏度的提高提出了新的见解。该方法准确、灵敏、快速,可满足大蒜中多种农药残留的检测要求。     

顶空气相色谱质谱联用测定厄贝沙坦中遗传毒性杂质N-亚硝基二甲胺和N-亚硝基二乙胺

采用顶空进样气相色谱-质谱联用法,对厄贝沙坦原料药中的遗传毒性杂质N-亚硝基二甲胺(NDMA)和N-亚硝基二乙胺(NDEA)进行同时测定。采用岛津SH-Rtx-Wax气相色谱柱程序升温进行分离,电子轰击电离源(EI)电离,选择离子监测(SIM)模式检测。结果表明NDMA和NDEA在10~500 ng/mL浓度范围内线性关系良好,检出限(LOD)分别为1.7 ng/mL和4.5 ng/mL,峰面积相对标准偏差(RSD)均小于2.4%。阴性及阳性样品加标回收率为100.6%~108.7%。该方法能够有效地检测原料药厄贝沙坦中NDMA和NDEA的含量。     

Identification of isopropyl substituted β-blocking agents in human urine by gas chromatography and tandem mass spectrometry

Summary A method for the sensitive detection of isopropyl substituted β-blocking agents in human urine is presented. The sample preparation step involves enzymatic hydrolysis, solid phase extraction and derivatisation withN-methyl-N-trimethylsilyl-trifluoroacetamide. The instrumental analysis was performed using gas chromatography-mass spectrometry with an ion trap mass spectromeler. The mass spectrometer was operated in the scan as well as in the MS-MS mode.