System for calculating the linear temperature-programmed retention indices of polycyclic aromatic compounds

Theoretical procedures have been used to predict linear temperature-programmed retention indices for polycyclic aromatic compounds. It is possible to calculate such indices for polycyclic aromatic compounds in some practical situations in which the compounds cannot be eluted during a simple linear temperature program. The theory has been tested for a number of polycyclic aromatic hydrocarbon (PAHs) in single- and multi-plateau temperature-programmed gas chromatography with SE-52 as the stationary phase. This method will extend the applicability of linear retention indices for the identification of the isomers of polycyclic aromatic compounds.     

Optimisation of the GC-MS conditions for the determination of the 15 EU foodstuff priority polycyclic aromatic hydrocarbons

European legislation has recently established a list of 15 priority polycyclic aromatic hydrocarbons (PAHs) to be monitored in foodstuff. Thus, the accurate determination of these compounds has become a highly relevant issue. The fact that some of these European Union (EU) PAHs differ from those typically analysed, requires the re-evaluation of the instrumental conditions for the proper determination of the new target compounds. In this study, the influence of the stationary phase and dimensions of the GC capillary column on the chromatographic resolution of the 15 EU PAHs has been investigated. Apolar (DB-5 type) and medium polar (DB-17 type) stationary phases with different lengths and film thickness have been evaluated for the separation of the target compounds, with special emphasis on those coelutions involving isomers such as the three benzofluoranthenes included in the EU PAHs. In addition, the influence of the injection technique and the column dimensions on the recovery of the high molecular mass PAHs has been studied. A programmable temperature vaporising (PTV) injector has been used in three different operational modes and the results were compared to those obtained using on-column injection. The experimental parameters involved in the injection step were optimised by using experimental design.     

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.     

尿中4种麻黄素类药物的GC／MSD测定

麻黄素、伪麻黄素、去甲麻黄素、去甲伪麻黄素作为兴奋剂药物及相关化合物被国际奥委会规定为禁用药物~[1],并对其作了限量规定~[2].前文曾用气相色谱法对该类药物进行了分离与测定~[3].本文采用色质联用技术,对含有这4种药物的尿样进行了分离,并采用选择离子检测(SIM)方式,以二苯胺为内标准物建立了对这4种药物同时定量的测定方法.本方法最低检测限为1μg/mL尿.其它兴奋剂药物及尿中化合物对检测无干扰.     

Application of selected ion monitoring to the analysis of triacylglycerols in olive oil by high temperature-gas chromatography/mass spectrometry

The analysis of the triacylglycerol (TAG) composition of oils is a very challenging task, since the TAGs have very similar physico-chemical properties. In this work, a high temperature-gas chromatographic method coupled to electron ionization-mass spectrometry (HT-GC/EI-MS), in the Selected Ion Monitoring (SIM) mode, method was developed for the analysis of TAGs in the olive oil; this is a method suitable for routine analysis. This method was developed using commercially available standard TAGs. The TAGs studied were separated according to their equivalent carbon number and degree of unsaturation. The peak assignment was carried out by locating the characteristic fragment ions having the same retention time on the SIM profile such as [RCO+74]⁺ and [RCO+128]⁺ ions, due to the fatty acyl residues on sn-1, sn-2 and sn-3 positions of the TAG molecule and the [M−OCOR]⁺ ions corresponding to the acyl ions. The developed method was very useful to eliminate the interferences that appeared in the mass spectrum since electron ionization can prevent satisfactory interpretation of spectra.     

多环芳烃指纹用于渤海采油平台原油的鉴别

采用气相色谱/质谱方法,对渤海海上4个不同区块、5个平台的6口油井原油进行了烷基化多环芳烃系列化合物和美国环保署（EPA）优先控制多环芳烃系列化合物的准确定性定量分析。通过多环芳烃原始指纹谱图、多环芳烃组分分布模式和特征比值的比较对上述原油进行鉴别。结果证明不同区块的原油中多环芳烃指纹信息不尽相同,即使在同一平台不同油井中所产的原油其指纹也存在一定差异。为确保原油鉴别的准确性,分析过程中必须在仪器的稳定性和样品前处理方面实施严格的质量控制措施。     

Supercritical fluid injection of high-molecular-weight polycyclic aromatic compounds in capillary supercritical fluid chromatography

A sample introduction system for capillary supercritical fluid chromatography, which allows the dissolution of the sample in the supercritical mobile phase before being introduced into the column, was constructed and evaluated. Supercritical n-pentane was shown to solvate high-molecular-weight polycyclic aromatic compounds that could not be solvated using typical liquid solvents. In addition, split injection of a supercritical fluid solution was found to be more reproducible than split injections of a liquid solution. The potential of such an injection system was demonstrated, although further developments are needed in order to make the technique of practically utility.     

Enhanced detection levels in the GC MS analysis of organometallic compounds,based on pre- and post-acquisition data manipulation

The different modes of data acquisition utilized in GC MS analyses of organometallic compounds are discussed. Comparisons of detection limits for each operating mode are reported and a lower detection limit of ca 5pg organotin compound injected onto the column was determined. Mass spectral data for a range of organotin compounds are presented to facilitate the choice of species suitable for single (selected) ion monitoring (SIM)     

Residential wood combustion: A source of atmospheric polycyclic aromatic hydrocarbons

Samples were taken of the atmospheric particulate matter over Fairbanks Alaska in the winter of 1985, and from wood stoves burning the major wood types locally available. These samples were then analyzed for polycyclic aromatic hydrocarbon (PAH). A PAH emission profile was determined from the wood stove samples and applied to the atmospheric samples to determine the residential wood combustion contribution to the local atmospheric particulate burden. Emission profiles for coal burning and automobile emissions for PAH were also used to estimate their relative contributions.     

气相色谱/质谱测定皮革及其制品中乙二醇醚类有机溶剂的残留量

建立了同时测定皮革及其制品中12种乙二醇醚类有机溶剂残留量的气相色谱/质谱-选择离子监测方法。以乙酸乙酯为萃取溶剂,在45℃下超声萃取皮革及其制品中的乙二醇醚类有机溶剂,萃取液经固相萃取柱净化后进行气相色谱/质谱-选择离子监测法测定,外标法定量。在信噪比（S/N）=3的条件下,乙二醇单乙醚（EGEE）的检出限为0.10 mg/kg,其余11种乙二醇醚类有机溶剂的检出限均小于0.05 mg/kg。在3个加标水平下,该方法的平均加标回收率为81.2%~95.5%,相对标准偏差（RSD）为1.4%~6.6%（n=9）。该方法简便快捷,灵敏度高,检出限远远低于欧盟法规《化学品的注册、评估、授权和限制》（REACH）的限量要求,适用于皮革及其制品中乙二醇醚类有机溶剂残留量的测定,为制定相关检测标准提供了参考。     

Polycyclic aromatic hydrocarbons (PAHs) in edible oils by gas chromatography coupled with mass spectroscopy

The occurrence of polycyclic aromatic hydrocarbons (PAHs) in nine edible oils of three categories of oil samples, such as soy bean oil, mustard oil and coconut oil, has been studied to determine the contamination degree of this type of oil samples. Eight major carcinogenic polycyclic aromatic hydrocarbons (PAHs), such as naphthalene, anthracene, phenanthrene, fluorene, pyrene, crysene, benzo(a)pyrene and benzo(a)anthracene, were identified and quantified in the extract of edible oils collected from Bangladeshi Markets by gas chromatography and mass spectroscopy. All of the carcinogenic PAHs are not present in the edible oils. A few of the carcinogenic PAHs are present in the oils but it is within the permissible limit. The results for the recoveries of naphthalene, fluorene, phenanthrene, anthracene, pyrene, crysene, benzo(a)anthracene and benzo(a)pyrene were in the range of 56–84%. The limit of detection (LOD) of the GC–MS method, established at signals three times that of the noise for naphthalene, fluorene, phenanthrene, anthracene, pyrene, crysene, benzo(a)anthracene and benzo(a)pyrene, was 2.0–2.5 ng, respectively.     

Determination of average molecular polarizabilities of polycyclic aromatic hydrocarbons directly from retention indices

Summary A significant correlation has been found between the retention indices of polycyclic aromatic hydrocarbons on non-polar stationary phases and the average molecular polarizabilities of the molecules separated on these phases. Equations have been derived for the determination of the average molecular polarizabilities, directly from the retention indices.     

固相萃取-气相色谱/质谱法同时测定涂料中的8种有机锡

建立了一种固相萃取（SPE）前处理、气相色谱-质谱（GC-MS）法同时测定涂料中8种有机锡的方法。样品采用阳离子交换固相萃取小柱净化,最佳固相萃取条件为：固相萃取小柱分别用5mL甲醇、7mL洗脱液（氯化铵、甲醇、冰乙酸的混合溶液）预洗,10mL甲醇活化;将用甲醇稀释的涂料样品上样后,用5mL甲醇淋洗,抽干2min,7mL乙酸-氯化铵甲醇溶液（10：90,V／V）洗脱溶液洗脱。洗脱液用四乙基硼化钠溶液衍生后,气相色谱-质谱法进行定性定量分析。结果表明：以标准加入法计算回收率,在1.68％-16.84%添加范围内,平均回收率在85％-105％之间,相对标准偏差均小于12％。     

Analysis of polycyclic aromatic hydrocarbons in solid sample material using a desorption device coupled to a GC/MS system

Summary Polycyclic aromatic hydrocarbons (PAH) today are ubiquitous detectable constituents of recent sediments. The compounds are adsorbed on particulate emissions and are thus transferred to the environment. To date the analysis of PAH in sediments, dust samples and plant material is based mainly on the application of solvent-extraction methods followed by liquid chromatography and/or gas chromatographic separation of the extracts.An alternative approach for the analysis of PAH in solid samples such as coal, sediments, dust samples and plant waxes is shown in this contribution. A commercially available device for the analysis of volatile compounds present in solid matter is connected on-line to a GC/MS system. The device enables the thermal desorption of hydrocarbons at a temperature of 320°C. Subsequently, the hydrocarbons trapped on the initial part of the capillary column are analyzed by GC/MS. The application of mass chromatography provides the possibility of detection and quantitation of PAH in complex mixtures even when they coelute with other compounds. The sample amount required varies between 1 and 10 mg depending on the hydrocarbon content.     

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。     

Development of an improved method for the determination of polycyclic aromatic hydrocarbons in mainstream tobacco smoke

A gas chromatograph/mass-selective detection (GC/MS) method has been developed and validated for the quantitation of 16 polycyclic aromatic hydrocarbons found in mainstream tobacco smoke condensate. The utilization of two types of solid-phase extraction media combined with capillary column technology removed matrix interferences, afforded a significant reduction in analysis run time, and increased accuracy. Also, the addition of a chilled impinger was used to trap semi-volatile polycyclic aromatic hydrocarbons and to provide more accurate data. This was done without sacrificing the repeatability, reproducibility, and precision obtained in previously published methods. The development and validation studies discussed in this paper resulted in an improved, robust analytical method capable of increasing laboratory capacity and reducing sample reporting time.     

Determination of polycyclic aromatic hydrocarbons in soy isoflavone nutraceutical products by gas chromatography coupled to triple quadrupole tandem mass spectrometry

Thirteen polycyclic aromatic hydrocarbons have been determined in soy‐based nutraceutical products. First, an optimization of extraction procedure was performed, and a solid–liquid extraction assisted by sonication and a dilute and shoot procedure were compared, selecting the dilute and shoot approach for the extraction of target compounds, utilizing a mixture of acetone/n‐hexane (1:1 v/v) as extractant solvent. After this, a clean‐up step was needed bearing in mind the complexity of these matrices. Dispersive solid‐phase extraction, using a mixture of C₁₈ and Zr‐Sep+ (25 mg/mL each) was used. The separation was achieved by gas chromatography and detection with triple quadrupole tandem mass spectrometry. For quantification purposes, matrix‐matched calibration was used. The validation was applied at three concentration levels (20, 100 and 250 μg/kg), obtaining recoveries between 70 and 120% and precision values equal to or lower than 23%. Limits of detection and quantification were below 8 and 20 μg/kg, respectively. The method was applied in 11 samples, detecting five polycyclic aromatic hydrocarbons at concentrations ranging from 4.1 to 18.5 μg/kg.     

Microcolumn liquid chromatography of polycyclic aromatic hydrocarbons and some isomeric compounds on cyclodextrin stationary phases

Preparative-grade bonded β- and γ-cyclodextrin stationary phases were used as the packing material of liquid chromato-graphic analytical microcolumns. Although the resulting columns are characterized by relatively low efficiency, the high selectivity of the cyclodextrin phases nevertheless allows their successful use for the separation of different classes of isomeric compounds that are difficult to resolve on conventional LC stationary phases. Examples of baseline (or almost baseline) separations of a number of isomeric compounds, including isomeric polycyclic aromatic hydrocarbons, are presented to demonstrate the analytical potential of such columns. Retention behavior of the separated isomers is discussed based on the structure of the solute molecule and the possibility of its inclusion into the molecular cavity of cyclodextrin stationary phases.     

GC/MS SIM法快速测定酒中的游离脂肪酸

本文介绍一种简单、快速、灵敏、直接分析酒中游离脂肪酸的测定方法。用涂有OV-17熔融石英毛细管柱。选择游离脂肪酸质谱图中的基峰离子m/z 60进行SIM检测。定量测定了茅台酒、珍酒及鸭溪窖酒中十二种游离脂肪酸。     

Determination of column selectivity toward polycyclic aromatic hydrocarbons

An empirical test is described for the evaluation of column selectivity in reversed-phase liquid chromatography. Using a test mixture of three polycyclic aromatic hydrocarbons (PAH), overall column selectivity toward PAH was assessed for over 20 different commercial C₁₈ columns. Retention behavior was correlated to phase type (i.e., monomeric and polymeric surface modification chemistry) for custom synthesized phases. A classification scheme is proposed in which commercial C₁₈ columns are grouped into three classes based on retention behavior: monomeric-like, polymeric-like, and intermediate phase selectivity toward PAH. Correlation of retention behavior of the test mixture with the separation of PAH mixtures and with more general column properties (e.g., phase thickness) is discussed.