Detection of Nandrolone and Boldenone Abuse in the Ovine by GC�CMS�CMS

Under European legislation, the use of anabolic steroids as growth promoters in meat production is prohibited. Currently, there is no internationally accepted method used for the detection of the potentially endogenous steroids nandrolone and boldenone in the ovine. In the current study, a multi-residue GC?CMS?CMS-based urinary assay has been validated for boldenone as well as the nandrolone metabolites 5??-estrane-3??,17??-diol and epinandrolone. Using a standard addition calibration line approach in pooled bovine urine, the method was linear between the endogenous concentrations and those augmented with 6,000 pg mL^?1. The method was then applied to populations of wether (n = 242) and ewe (n = 237) ovine animals in order to establish urinary thresholds for detecting nandrolone and boldenone abuse. A statistical model (the Chebyshev inequality) was used to produce threshold concentrations for each analyte. Adjustment of the nandrolone metabolite data for specific gravity, a measure of the hydration status of the animal, allowed the effective thresholds to be reduced; potentially leading to a lower number of false positives. Furthermore, the proposed epinandrolone confirmatory thresholds (38,628 and 57,950 pg mL^?1 in wethers and ewes, respectively) were found to be effective in detecting abuse of nandrolone for at least 1 month post-dose of this steroid. However, further studies would be required to assess the efficacy of the proposed boldenone confirmatory thresholds (19,857 and 56,080 pg mL^?1 in wethers and ewes, respectively) since data on its excretion following administration to the ovine are lacking.     

Derivatization Method for Determination of Nitrosamines by GC�CMS

Gas chromatography/low-resolution mass spectrometry with electron impact source was applied to detect eight nitrosamines (NAs). NAs were first denitrosated by a mixed solution of hydrobromic and acetic acids, followed by sulfonylation with p-toluenesulfonyl chloride. Variables affecting the denitrosation and sulfonylation, such as temperature, time, pH and reagent concentration, were optimized. Comparison of the determination of NAs with and without derivatization was performed. Results showed that better chromatographic behavior and larger mass response were obtained after derivatization, and instrumental detection limits ranged from 0.016 to 0.053 ng, a nearly 20-fold decrease of those without derivatization. The proposed method provided an alternative to performing accurate qualitative and quantitative analysis of NAs with expensive high-resolution mass spectrometry or thermal energy analyzer.     

Reproducibility of Programmed-Temperature Retention Indices under Average Linear Velocity Carrier Gas Control of GC and GC�CMS

Programmed-temperature retention indices (PTRIs) are useful for the identification and quantification of chemicals by means of GC and GC/MS. To obtain reproducible PTRIs, we studied the influence of average linear velocity and column length under the constant average linear velocity control (CVC) using 55 pesticides and 33 fatty acid methyl esters. The PTRIs decreased with increasing average linear velocity, and the degree of decrease differs with the compounds. The PTRIs, however, were almost constant as long as the same average linear velocity was used even if the column length was changed. In addition, the correlation between the variation ratio in PTRI and the increase in average linear velocity was linear. Using the linear relationship between PTRIs and average linear velocities under CVC, highly reproducible PTRIs were obtained even if the capillary column length changes. Furthermore, the PTRIs determined by GC with FID, ECD, and FPD under atmospheric pressure were applied to GC/MS under vacuum or vice versa. From these results, it was confirmed that because CVC provides reproducible retention indices, CVC is advantageous for qualitative and quantitative analysis by GC and GC/MS.     

Application of Dispersive Liquid�CLiquid Microextraction for the Analysis of Six Fungicides in Fruit Samples by GC�CECD

A novel approach for the determination of six fungicides (triadimefon, procymidone, hexaconazole, myclobutanil, diniconazole and iprodione) in fruit samples is presented. Analytes were extracted using the dispersive liquid?Cliquid microextraction technique and determined by GC?CECD. Parameters affecting the dispersive liquid?Cliquid microextraction performance, such as the kind and volume of extraction and dispersive solvents, extraction time and salt concentration, were studied and optimized. Under the optimum extraction conditions, the linearities of the method were obtained in the range of 0.5?C20.0 ??g kg^?1 for triadimefon, hexaconazole, diniconazole and procymidone, and 1.0?C40.0 ??g kg^?1 for myclobutanil and iprodione, with the correlation coefficients ranging from 0.9902 to 0.9995. The enrichment factors ranged from 685 to 820 and the extraction recoveries ranged from 81.3 to 98.4%. The relative standard deviations varied from 3.1 to 7.8%. The limits of detection of the method were in the range of 0.02?C0.12 ??g kg^?1. Results showed that the method we proposed can meet the requirements for the determination of target fungicides in fruit samples. Several compounds considered in this study were found in fruit samples.     

Magnetic Nanoparticle-Based Micro-Solid Phase Extraction and GC�CMS Determination of Oxadiargyl in Aqueous Samples

A new facile, rapid, inexpensive, and sensitive method based on magnetic micro-solid phase extraction (M-??-SPE) coupled to gas chromatography?Cmass spectrometry (GC?CMS) was developed for determination of the herbicide oxadiargyl in environmental water samples. The feasibility of employing non-modified magnetic nanoparticles (MNPs) as sorbent was examined and applied to perform the extraction process. Influential parameters affecting the extraction efficiency along with desorption conditions were investigated and optimized. The limit of detection (LOD, S/N = 3) and limit of quantification (LOQ, S/N = 10) of the method under optimized conditions were 0.005 and 0.030 ng mL^?1, respectively. The relative standard deviations (RSD) (n = 3) at a concentration of 0.10 ng mL^?1 was 11%. The calibration curve of oxadiargyl showed linearity in the range of 0.050?C0.50 ng mL^?1. The developed method was successfully applied to the extraction of oxadiargyl from spiked tap water and Zayande-Rood River water samples and the relative recoveries of 98 and 94% were obtained, respectively.     

GC�CMS Determination of PAHs in Fish Samples Following Salting-out-Assisted Solvent Extraction-Gel Permeation Chromatography

A fast and effective sample cleanup procedure for the quantification of polycyclic aromatic hydrocarbons (PAHs) in fish samples is presented. The procedure involved extraction of fish samples using acetonitrile and cleanup by an automated gel-permeation chromatography (GPC) following liquid?Cliquid partition into n-hexane. The extracted samples were analyzed by gas chromatography-mass spectrometry (GC?CMS). Electron ionization was employed in a single analysis for the determination of PAHs in the selected ion monitoring mode. Three different solvents were studied for the extraction step: acetonitrile/n-hexane, methanol/n-hexane and acetone/n-hexane. The best solvent was found to be acetonitrile/n-hexane. The cleanup technique resulted in a good separation of analytes from co-extractive matrix compounds.     

Ultrasound-Assisted Dispersive Liquid�CLiquid Microextraction Combined with Low Solvent Consumption for Determination of Polycyclic Aromatic Hydrocarbons in Seawater by GC�CMS

Ultrasound-assisted dispersive liquid?Cliquid microextraction (USA-DLLME) with low solvent consumption was demonstrated for gas chromatography-mass spectrometry (GC?CMS) determination of 16 typical polycyclic aromatic hydrocarbons (PAHs) in seawater samples. Factors affecting the extraction process, such as extraction and dispersive solvent, phase ratio, temperature, extraction and centrifugation time, were investigated thoroughly and optimized. The linear range was 20?C2,000 ng L^?1 except for acenaphthylene (Acy) at 10?C2,000 ng L^?1 and phenanthrene (Phe), fluoranthene (Flu) and pyrene (Py) all at 5?C2,000 ng L^?1. Enrichment factors (EFs) ranging from 722 to 8,133 were obtained, achieving limits of detection at 1.0?C10.0 ng L^?1. The method attained good precision (relative standard deviation, RSD) from 3.4 to 14.2% for spiked 50 ng L^?1 individual PAHs standards. Method recoveries were in the range 87?C124% and 70?C127% for spiked samples from simulated seawater and beach seawater, respectively. The proposed USA-DLLME helped to obtain about 1.1?C10 times higher EFs in a minimum amount of solvent and in less time than traditional DLLME.     

GC�CMS Coupled with Hollow-Fiber Drop-to-Drop Solvent Microextraction for Determination of Antidepressants Drugs in Human Blood Sample

A simple, rapid and sensitive hollow-fiber with drop-to-drop solvent microextraction (HF-DDSME) combined with gas chromatography?Cmass spectrometry (GC?CMS) has been successfully developed for extraction and determination of antidepressants drugs (AD) in blood sample. The parameters that affect the separation and preconcentration of AD from sample solution were investigated. Calibration curve obtained for three AD were in the range of 100?C1,000; 150?C1,200; and 80?C1,200 ng mL^?1 for amitriptyline, imipramine, and promethazine, respectively, with correlation coefficient (R ² ) between 0.990 and 0.997. The limit of detection (LOD) obtained for amitriptyline, imipramine and promethazine was 25, 30 and 18 ng mL^?1, respectively. The developed method has been successfully applied for the determination of AD concentration in blood sample, and the recoveries for the spiked samples were in the range of 92.3?C97.6%. The sample preparation procedure is very simple, effective and virtually solvent-free, and indicated to be a good alternative for the traditional liquid?Cliquid extraction. Finally, the proposed method was successfully applied for the determination of drug concentration of AD in human blood sample.     

DETECTION AND QUANTITATION OF TRACE ETHYL CARBAMATE IN ALCOLLOLIC BEVERAGES BY GC/GC AND GC/GC/MS

Analytical difficulties encountered in the determination of ethyl carbamate, aknown cancinogen, in a wide variety of wines and spirits have been overcome by spe-cific, sensitive GC/GC and CC/CC/MS methods with a relatively shorter extractionprocedure. The lowest detection limits were estimated to be 0. 1 and 0. 01μg/L forGC/GC and GC/GC/MS respectively. The RSD of the GC/GC method was 2. 5%.     

GC,GC/MS法定性定量分析鱼油中的脂肪酸

本文介绍了一种用色谱-质谱联用仪(GC/MS),气相色谱仪(GC),定性、定量地分析测定鱼油脂中各种主要脂肪酸百分含量的方法。此法的分析过程比较直观和简单。样品在分析之前需要进行甲酯化衍生制备。鱼油脂中从11碳到22碳范围内的20几种主要脂肪酸均可准确地定性并获得定量结果。     

A Hexagonally Ordered Nanoporous Silica-Based Fiber Coating for SPME of Polycyclic Aromatic Hydrocarbons from Water Followed by GC�CMS

A highly porous fiber coating material was prepared and functionalized with 3-amino propyl triethoxysilane (APTES) on hexagonally ordered nanoporous silica (SBA-15). Applicability of this coating was assessed employing a laboratory made solid-phase microextraction (SPME) device and gas chromatography?Cmass spectrometry for the simultaneous sampling and determination of trace polycyclic aromatic hydrocarbons (PAHs) from aqueous sample solutions. A one at the time optimization strategy was applied to investigate and optimize important extraction parameters such as extraction temperature, extraction time, ionic strength and sonication time. In the optimum conditions, the relative standard deviations for deionized water, spiked with selected PAHs were between 3.3 and 7.7% (n = 3), and detection limits for the studied compounds were 4.2 and 26.1 pg mL^?1. No significant change was observed in the extraction efficiency of the new SPME fiber, over 50 extractions. The proposed method was successfully applied to the extraction and determination of PAHs in the waste water samples.     

Sensoric potential of gold�Csilver core�Cshell nanoparticles

The sensitivities of five different core-shell nanostructures were investigated towards changes in the refractive index of the surrounding medium. The shift of the localized surface plasmon resonance (LSPR) maximum served as a measure of the (respective) sensitivity. Thus, gold-silver core-shell nanoparticles (NPs) were prepared with different shell thicknesses in a two-step chemical process without the use of any (possibly disturbing) surfactants. The measurements were supported by ultramicroscopic images in order to size the resulting core-shell structures. When compared to sensitivities of nanostructures reported in the literature with those of the (roughly spherical) gold-silver core-shell NPs, the latter showed comparable (or even higher) sensitivities than gold nanorods. The experimental finding is supported by theoretical calculation of optical properties of such core-shell NP. Extinction spectra of ideal spherical and deformed core-shell NPs with various core/shell sizes were calculated, and the presence of an optimal silver shell thickness with increased sensitivity was confirmed. This effect is explained by the existence of two overlapping plasmon bands in the NP, which change their relative intensity upon change of refractive index. Results of this research show a possibility of improving LSPR sensor by adding an extra metallic layer of certain thickness.     

Comprehensive multidimensional separation methods by hyphenation of single-photon ionization time-of-flight mass spectrometry (SPI-TOF-MS) with GC and GC×GC

One- and comprehensive two-dimensional gas chromatography were hyphenated with soft photoionization mass spectrometry. The characteristics of these two- and three-dimensional comprehensive separation techniques are discussed in detail. Using the innovative electron beam pumped excimer light source (EBEL) for single-photon ionization (SPI), organic molecules with ionization energies (E _i ) of below 9.8 eV can be detected by a time-of-flight mass spectrometer (TOF-MS). SPI with 126 nm vacuum ultraviolet (VUV) photons enables the universal and soft ionization of organic molecules. SPI-TOF-MS hyphenated to one-dimensional gas chromatography results in a comprehensive two-dimensional separation method (GC×MS). To demonstrate this, diesel fuel was analyzed, and the resulting GC×MS chromatograms are discussed in depth. A three-dimensional separation method was also realized by combining comprehensive two-dimensional gas chromatography (GC×GC) with SPI-MS. In the resulting separation space, constituents originating from mineral oil diesel blended with biodiesel were dispersed along the two GC separation axes, while the molecular mass axis served as a third separation dimension.     

用毛细管GC／MS和GC／FTIR研究挥发油的化学成分

本文用毛细管GC/MS和GC/FTIR对异叶青兰和鼠曲草两种植物挥发油的化学成分进行了研究,讨论了两种方法分析挥发油化学成分的优点和局限性。     

GC和GC／MS分析脱硫细菌代谢二苯并噻吩的产物

从茂名炼油厂周围土壤中分离得到一株可脱除二苯并噻吩（DBT）的细菌YC－LI－1用GC／MS方法定性鉴定了该细菌脱除DBT的代谢的有机产物为2－羟基联苯（1－OHBP）,此外试验还证明了DBT中的硫原子代谢为水溶性的硫酸盐,用GC方法测定了该菌种将DBT代谢为2－羟基联苯的转化率,分析结果表明该菌种可有效代谢DBT,转化率达90％以上。     

Elucidation of the Structures of Metabolites of Picroside II in Rat Bile by LC�CESI�CIT�CMS

Picroside II is one of the main active constituents of Picrorhiza kurroa, which has hepatoprotective, anticholestatic, antioxidant, and immune-modulating activity. To gain an understanding of the biotransformation of picroside II in vivo, liquid chromatography?Celectrospray ionization ion-trap mass spectrometry (LC?CESI?CIT?CMS) was used to investigate the metabolism of picroside II in rats after intravenous administration of a single dose. This method could simultaneously determine picroside II and its metabolites in rat bile. The bile samples were purified by use of a C₁₈ solid-phase extraction (SPE) cartridge and were separated on a Hypersil ODS2 C₁₈ analytical column. Two phase II metabolites of picroside II in rat bile were characterized, and elucidation of their structures was performed by comparing changes in molecular masses (??M), retention times, and MS² spectral patterns of metabolites with those of the parent drug. Two metabolites identified for the first time in this research were glucuronide and sulfate conjugates.     

岛津GC50周年庆典

2006年12月16日下午，岛津公司在具有百年历史的北京饭店莱佛士B1宝石厅隆重举行“岛津GC50周年庆典”活动。岛津公司荣幸地邀请到国家科技部条件财务司吴波尔司长、国家科技部国家科技基础条件平台中心张渝英主任、中国分析测试协会副理事长兼秘书长王顺昌先生、中国色谱学会理事长中科院大连化物所张玉奎院士、广东色谱学会张汉英理事长、中国疾病预防控制中心营养与食品安全所化学污染物监控室副主任赵云峰研究员以及来自全国各地的政府官员、相关学者及岛津新老用户近200位宾客参加了此次庆典活动。     

Determination of Pilocarpine in Human Plasma by LC�CAPCI�CMS�CMS and Application to a Pharmacokinetic Study

A sensitive, specific and rapid high performance liquid chromatography?Catmospheric pressure chemical ionization source-tandem mass spectrometry (LC-APCI-MS-MS) method for the determination of pilocarpine in human plasma was developed and validated. The method is based on liquid?Cliquid extraction, followed by a reversed-phase liquid chromatographic separation, and detected by means of tandem mass spectrometry. The linear calibration curve covered a concentration range of 2?C500 ??g L^?1. The intra- and inter-day precisions for pilocarpine were <10% and the accuracies were between 90 and 110%. The method was applied successfully to a pharmacokinetic study involving 20 healthy Chinese male volunteers after oral administration of 6 mg pilocarpine.     

Determination of Volatile Nitrosamines in Latex Products by HS-SPME�CGC�CMS

Nitrosamines which have been detected in various latex products are carcinogens. The method for determination of volatile nitrosamines in latex products was developed using a combination of headspace solid phase micro-extraction (HS-SPME) and gas chromatography?Cmass spectrometry (GC?CMS). A carboxen/polydimethylsiloxane (CAR/PDMS) fiber was used for HS-SPME involving the following variables: (1) agitation conditions, (2) extraction temperature (3) extraction time, and (4) salt concentration. The instrument performances of three detection systems including GC combined thermal energy analyzer, nitrogen chemiluminescence detector and MS were evaluated. The agitation conditions including magnetic stirring and ultrasonication were investigated by the comparison of extraction efficiency of HS-SPME for nitrosamines. Obtained optimal detection conditions of nitrosamines were HS-SPME at 45 °C for 60 min assisted with magnetic stirring and saturated NaCl followed by GC?CMS. To evaluate this method performance, the commercial products including eleven latex products (gloves, balloons and condoms) and four liquid silicone nipples were analyzed with the method. The results revealed that the method is suitable for simple and effective determination of nitrosamines in latex products. The advantage of this HS-SPME?CGC?CMS method is simple treatment, fast analysis, adequate sensitivity and without organic solvent.     

Uncertainty Analysis of Chlormequat Residue in Fruits by LC�CMS�CMS

A method for determination of chlormequat (CCC) residue in fruits by liquid chromatography?Ctandem mass spectrometry (LC?CMS?CMS) was developed. Residue of CCC was extracted from samples with methanol?Cwater (v/v, 1:1) containing 1.0% acetic acid, cleaned up by strong cationic exchange (SCX) cartridge, and then determined by LC?CMS?CMS. The method showed good linearity over the concentration range 0.002?C5.0 mg kg^?1 with correlation coefficient above 0.997. The limit of detection (LOD) and limit of quantitation (LOQ) for CCC were 5 × 10^?4 mg kg^?1 (S/N = 3) and 0.002 mg kg^?1 (S/N = 10), respectively. Recoveries for CCC at three spiked levels (0.025, 0.050, and 0.20 mg kg^?1) were in the range 80?C102%. Estimation of measurement uncertainty was calculated for CCC at the level of 0.025 mg kg^?1 in fruits. The results demonstrated that the uncertainty of recovery was the main contribution to the combined standard uncertainty. The relative combined standard uncertainties associated with the method ranged from 11 to 13%, depending on the sample matrices.